AGW Observer

Observations of anthropogenic global warming

Archive for September, 2009

General papers on AGW

Posted by Ari Jokimäki on September 30, 2009

This list contains papers that provide general reviews, observations, and arguments on the anthropogenic global warming. I especially recommend Keller (2007) as a general overview of recent problematics of the issue. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

UPDATE (April 19, 2012): Sawyer (1972) added. Thanks to J Bowers for pointing it out (in another paperlist thread).
UPDATE (April 17, 2012): Hansen et al. (1981) added. Thanks to Barry for pointing it out (in another paperlist thread).
UPDATE (November 17, 2010): Sloan & Wolfendale (2010) removed as apparently non-peer-reviewed document. Thanks to Barry for pointing this out, see the comment section below.
UPDATE (March 25, 2010): Füssel (2009) added, thanks to PeterPan for pointing it out, see the comment section below.
UPDATE (February 3, 2010): Sloan & Wolfendale (2010) added.
UPDATE (December 9, 2009): Mitchell (1989) added.

An updated assessment of the risks from climate change based on research published since the IPCC Fourth Assessment Report – Füssel (2009) “This paper presents an updated assessment of the risks from anthropogenic climate change, based on a comprehensive review of the pertinent scientific literature published since finalisation of the AR4. Many risks are now assessed as stronger than in the AR4, including the risk of large sea-level rise already in the current century, the amplification of global warming due to biological and geological carbon-cycle feedbacks, a large magnitude of “committed warming” currently concealed by a strong aerosol mask, substantial increases in climate variability and extreme weather events, and the risks to marine ecosystems from climate change and ocean acidification.” [Full text]

Assessing dangerous climate change through an update of the Intergovernmental Panel on Climate Change (IPCC) “reasons for concern” – Smith et al. (2009) “Here, we describe revisions of the sensitivities of the RFCs [reasons for concern] to increases in GMT [global mean temperature] and a more thorough understanding of the concept of vulnerability that has evolved over the past 8 years.” [Full text]

Global warming: a review of this mostly settled issue – Keller (2009) “This review attempts to update what is known and in particular what advances have been made in the past 5 years or so. It does not attempt to be comprehensive. Rather it focuses on the most controversial issues, which are actually few in number.”

Attributing physical and biological impacts to anthropogenic climate change – Rosenzweig et al. (2008) “Significant changes in physical and biological systems are occurring on all continents and in most oceans, with a concentration of available data in Europe and North America. Most of these changes are in the direction expected with warming temperature. Here we show that these changes in natural systems since at least 1970 are occurring in regions of observed temperature increases, and that these temperature increases at continental scales cannot be explained by natural climate variations alone.” [Full text]

Tipping point: Perspective of a climatologist – Hansen (2008) “I describe how two fundamental properties of our climate system, its predominance of “positive feedbacks” and its ponderous inertia, have together brought climate to a great tipping point, a planetary emergency. I then discuss emerging impacts of climate change on the wild. Finally I summarize fundamental data on fossil fuels, the main driver of climate change, providing an outline of actions needed to reverse the forces driving climate change.” [Full text]

Global Warming 2007. An Update to Global Warming: The Balance of Evidence and Its Policy Implications – Keller (2007) “In the four years since my original review (Keller[25]; hereafter referred to as CFK03), research has clarified and strengthened our understanding of how humans are warming the planet. So many of the details highlighted in the IPCC’s Third Assessment Report[21] and in CFK03 have been resolved that I expect many to be a bit overwhelmed, and I hope that, by treating just the most significant aspects of the research, this update may provide a road map through the expected maze of new information.” [Full text]

Global warming – Houghton (2005) “‘Global warming’ is a phrase that refers to the effect on the climate of human activities, in particular the burning of fossil fuels (coal, oil and gas) and large-scale deforestation, which cause emissions to the atmosphere of large amounts of ‘greenhouse gases’, of which the most important is carbon dioxide. Such gases absorb infrared radiation emitted by the Earth’s surface and act as blankets over the surface keeping it warmer than it would otherwise be. Associated with this warming are changes of climate.” [Full text]

The Scientific Consensus on Climate Change – Oreskes (2004) “Policy-makers and the media, particularly in the United States, frequently assert that climate science is highly uncertain. … The scientific consensus is clearly expressed in the reports of the Intergovernmental Panel on Climate Change (IPCC). … IPCC is not alone in its conclusions. In recent years, all major scientific bodies in the United States whose members’ expertise bears directly on the matter have issued similar statements. … This analysis shows that scientists publishing in the peer-reviewed literature agree with IPCC, the National Academy of Sciences, and the public statements of their professional societies.” [Full text]

Global Warming: The Balance of Evidence and Its Policy Implications – Keller (2003) “This review attempts to update what is known and in particular what advances have been made in the past 5 years or so. It does not attempt to be comprehensive. Rather it focuses on the most controversial issues, which are actually few in number.” [Full text]

Climate Science: An Empirical Example of Postnormal Science – Bray & von Storch (1999) “This paper addresses the views regarding the certainty and uncertainty of climate science knowledge held by contemporary climate scientists. … The data for the analysis is drawn from a response rate of approximately 40% from a survey questionnaire mailed to 1000 scientists in Germany, the United States, and Canada, and from a series of in-depth interviews with leading scientists in each country. … Almost all scientists agreed that the skill of contemporary models is limited. … The international consensus was, however, apparent regarding the utility of the knowledge to date: climate science has provided enough knowledge so that the initiation of abatement measures is warranted.” [Full text]

The “Greenhouse” Effect and Climate Change – Mitchell (1989) A review paper going through the basics of the issue. “The presence of radiatively active gases in the Earth’s atmosphere (water vapor, carbon dioxide, and ozone) raises its global mean surface temperature by 30 K, making our planet habitable by life as we know it. There has been an increase in carbon dioxide and other trace gases since the Industrial Revolution, largely as a result of man’s activities, increasing the radiative heating of the troposphere and surface by about 2 W m−2.” [Full text]

Climate Impact of Increasing Atmospheric Carbon Dioxide – Hansen et al. (1981) “The global temperature rose by 0.2°C between the middle 1960’s and 1980, yielding a warming of 0.4°C in the past century. This temperature increase is consistent with the calculated greenhouse effect due to measured increases of atmospheric carbon dioxide. Variations of volcanic aerosols and possibly solar luminosity appear to be primary causes of observed fluctuations about the mean trend of increasing temperature. It is shown that the anthropogenic carbon dioxide warming should emerge from the noise level of natural climate variability by the end of the century, and there is a high probability of warming in the 1980’s. Potential effects on climate in the 21st century include the creation of drought-prone regions in North America and central Asia as part of a shifting of climatic zones, erosion of the West Antarctic ice sheet with a consequent worldwide rise in sea level, and opening of the fabled Northwest Passage.” J. Hansen, D. Johnson, A. Lacis, S. Lebedeff, P. Lee, D. Rind and G. Russell, Science 28 August 1981: Vol. 213 no. 4511 pp. 957-966, DOI: 10.1126/science.213.4511.957. [Full text]

Man-made Carbon Dioxide and the “Greenhouse” Effect – Sawyer (1972) “In spite of the enormous mass of the atmosphere and the very large energies involved in the weather systems which produce our climate, it is being realized that human activities are approaching a scale at which they cannot be completely ignored as possible contributors to climate and climatic change.”
J. S. Sawyer, Nature 239, 23 – 26 (01 September 1972); doi:10.1038/239023a0.
[Full text]

Closely related

IPCC reports are an excellent resource for a thorough review on the subject.


Posted in AGW evidence | 9 Comments »

Papers on global carbon cycle

Posted by Ari Jokimäki on September 28, 2009

This list contains papers on global carbon cycle, with emphasis on observations. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

UPDATE (January 14, 2010): Tans et al. (1990) added.
UPDATE (January 5, 2010): Knorr (2009) added.
UPDATE (December 9, 2009): Le Quéré et al. (2009) added.
UPDATE (December 4, 2009): Sundquist (1993) added.
UPDATE (September 29, 2009): Section “Carbon cycle in past climate” added, Elsig et al. (2009) added (thanks to John Cook for pointing out this paper, see discussion section below), and Hughen et al. (2004) added.

Carbon cycle in modern climate

Is the airborne fraction of anthropogenic CO2 emissions increasing? – Knorr (2009) “This study re-examines the available atmospheric CO2 and emissions data including their uncertainties. It is shown that with those uncertainties, the trend in the airborne fraction since 1850 has been 0.7 ± 1.4% per decade, i.e. close to and not significantly different from zero. The analysis further shows that the statistical model of a constant airborne fraction agrees best with the available data if emissions from land use change are scaled down to 82% or less of their original estimates. Despite the predictions of coupled climate-carbon cycle models, no trend in the airborne fraction can be found.” [Full text]

Trends in the sources and sinks of carbon dioxide – Le Quéré et al. (2009) “Between 1959 and 2008, 43% of each year’s CO2 emissions remained in the atmosphere on average; the rest was absorbed by carbon sinks on land and in the oceans. In the past 50 years, the fraction of CO2 emissions that remains in the atmosphere each year has likely increased, from about 40% to 45%, and models suggest that this trend was caused by a decrease in the uptake of CO2 by the carbon sinks in response to climate change and variability.”

Understanding and managing the global carbon cycle – Birdsey et al. (2009) A brief review article that focuses on USA situation but lot of it is also globally relevant. [Link to PDF]

Interannual variability of the global carbon cycle (1992–2005) inferred by inversion of atmospheric CO2 and δ13CO2 measurements – Rayner et al. (2008) “We present estimates of the surface sources and sinks of CO2 for 1992–2005 deduced from atmospheric inversions. … The results suggest that interannual variability is dominated by the tropical land. Statistically significant variability in the tropical Pacific supports recent ocean modeling studies in that region. The northern land also shows significant variability.”

Understanding and managing the global carbon cycle – Grace (2004) A review article. “There is broad agreement among the results from these methods: carbon sinks are currently found in tropical, temperate and boreal forests as well as the ocean. … However, on a global scale the effect of the terrestrial sinks (absorbing 2–3 billion tonnes of carbon per year) is largely offset by deforestation in the tropics (losing 1–2 billion tonnes of carbon per year).” [Link to PDF]

Carbon cycling in earth systems—a soil science perspective – Janzen (2004) A review article. “The carbon cycle binds together earth’s ecosystems and their inhabitants. My intent is to review the global carbon cycle, examine how humans have modified it, and contemplate (from a soil science bias) the new questions that await us on a changing earth. These thoughts are proffered, not to propose a way forward, but to invite conversation about opportunities that await us.” [Link to PDF]

Satellite Data Help Predict Terrestrial Carbon Sinks – Potter et al. (2003) “Accurate estimates of how much CO2 ecosystems can absorb will be fundamental to successful systems of international carbon accounting. NASA’s Terra satellite platform, with the moderate resolution imaging spectroradiometer (MODIS) instrument on board, provides a new era of observations for carbon cycle assessments. Direct input of satellite vegetation index “greenness” data from the MODIS sensor into ecosystem simulation models can be used to estimate spatial variability in monthly net primary production (NPP), biomass accumulation, and litter fall inputs to soil carbon pools.”

Towards robust regional estimates of CO2 sources and sinks using atmospheric transport models – Gurney et al. (2002) “Here we report estimates of surface–atmosphere CO2 fluxes from an intercomparison of atmospheric CO2 inversion models (the TransCom 3 project), which includes 16 transport models and model variants. … Overall, carbon fluxes integrated over latitudinal zones are strongly constrained by observations in the middle to high latitudes. Further significant constraints to our understanding of regional carbon fluxes will therefore require improvements in transport models and expansion of the CO2 observation network within the tropics.”

The Global Carbon Cycle: A Test of Our Knowledge of Earth as a System – Falkowski et al. (2000) A review article. “Our knowledge of the carbon cycle within the oceans, terrestrial ecosystems, and the atmosphere is sufficiently extensive to permit us to conclude that although natural processes can potentially slow the rate of increase in atmospheric CO2, there is no natural “savior” waiting to assimilate all the anthropogenically produced CO2 in the coming century.” [Link to PDF]

Global and hemispheric CO2 sinks deduced from changes in atmospheric O2 concentration – Keeling et al. (1996) “The data are consistent with a budget in which, for the 1991–94 period, the global oceans and the northern land biota each removed the equivalent of approximately 30% of fossil-fuel CO2 emissions, while the tropical land biota as a whole were not a strong source or sink.”

Terrestrial ecosystems and the carbon cycle – Schimel (1995) A review article (?) “The terrestrial biosphere plays an important role in the global carbon cycle. In the 1994 Intergovernmental Panel Assessment on Climate Change (IPCC), an effort was made to improve the quantification of terrestrial exchanges and potential feedbacks from climate, changing CO2, and other factors; this paper presents the key results from that assessment, together with expanded discussion.”

Atmospheric carbon dioxide and the ocean – Siegenthaler & Sarmiento (1993) A review article. “The ocean is a significant sink for anthropogenic carbon dioxide, taking up about a third of the emissions arising from fossil-fuel use and tropical deforestation. Increases in the atmospheric carbon dioxide concentration account for most of the remaining emissions, but there still appears to be a ‘missing sink’ which may be located in the terrestrial biosphere.” [Link to PDF]

The global carbon dioxide budget – Sundquist (1993) “The increase in atmospheric CO2 levels during the last deglaciation was comparable in magnitude to the recent historical increase. However, global CO2 budgets for these changes reflect fundamental differences in rates and in sources and sinks. The modern oceans are a rapid net CO2 sink, whereas the oceans were a gradual source during the deglaciation. Unidentified terrestrial CO2 sinks are important uncertainties in both the deglacial and recent CO2 budgets. The deglacial CO2 budget represents a complexity of long-term dynamic behavior that is not adequately addressed by current models used to forecast future atmospheric CO2 levels.” [Link to PDF]

Observational Constrains on the Global Atmospheric CO2 Budget – Tans et al. (1990) “Observed atmospheric concentrations of CO2 and data on the partial pressures of CO2 in surface ocean waters are combined to identify globally significant sources and sinks of CO2. The atmospheric data are compared with boundary layer concentrations calculated with the transport fields generated by a general circulation model (GCM) for specified source-sink distributions. In the model the observed north-south atmospheric concentration gradient can be maintained only if sinks for CO2 are greater in the Northern than in the Southern Hemisphere. The observed differences between the partial pressure of CO2 in the surface waters of the Northern Hemisphere and the atmosphere are too small for the oceans to be the major sink of fossil fuel CO2. Therefore, a large amount of the CO2 is apparently absorbed on the continents by terrestrial ecosystems.”

The global carbon cycle – Post et al. (1990) “This article presents important advances in carbon-cycle research, inventories the world’s carbon reservoirs, and discusses what is known about the role of oceanic and terrestrial systems in exchanging CO{sub 2} with the atmosphere. Finally, a new global systems approach is described that shows promise in resolving current difficulties.” [Link to PDF]

Carbon cycle in past climate

Stable isotope constraints on Holocene carbon cycle changes from an Antarctic ice core – Elsig et al. (2009) “Here we present a highly resolved atmospheric 13C record for the past 11,000 years from measurements on atmospheric CO2 trapped in an Antarctic ice core. From mass-balance inverse model calculations performed with a simplified carbon cycle model, we show that the decrease in atmospheric CO2 of about 5 parts per million by volume (p.p.m.v.). The increase in 13C of about 0.25 [per mil] during the early Holocene is most probably the result of a combination of carbon uptake of about 290 gigatonnes of carbon by the land biosphere and carbon release from the ocean in response to carbonate compensation of the terrestrial uptake during the termination of the last ice age. The 20 p.p.m.v. increase of atmospheric CO2 and the small decrease in 13C of about 0.05 during the later Holocene can mostly be explained by contributions from carbonate compensation of earlier land-biosphere uptake and coral reef formation, with only a minor contribution from a small decrease of the land-biosphere carbon inventory.”

14C Activity and Global Carbon Cycle Changes over the Past 50,000 Years – Hughen et al. (2004) “Reconstructed 14C activities varied substantially during the last glacial period, including sharp peaks synchronous with the Laschamp and Mono Lake geomagnetic field intensity minimal and cosmogenic nuclide peaks in ice cores and marine sediments. Simulations with a geochemical box model suggest that much of the variability can be explained by geomagnetically modulated changes in 14C production rate together with plausible changes in deep-ocean ventilation and the global carbon cycle during glaciation.” [Link to PDF]

Closely related

Integrated Global Carbon Observation Theme – Ciais et al. (2004) A Strategy to Realize a Coordinated System of Integrated Global Carbon Cycle Observations.

The Global Carbon Cycle – Bolin et al. (1979) “The present publication is the result of the Workshop on the Carbon Cycle, held at Ratzeburg, Federal Republic of Germany, 2126 March 1977. The carbon cycle is the most important and most complex cycle of all, as it is the pacemaker for the other cycles which in turn codetermine flow rates in the carbon cycle.”

Posted in AGW evidence | 6 Comments »

Papers on laboratory measurements of CO2 absorption properties

Posted by Ari Jokimäki on September 25, 2009

This is a list of papers on laboratory measurements of the absorption properties of carbon dioxide. In the context of these paperlists this is a difficult subject because only few of the papers are freely available online, so we have to settle on abstracts only (of course, interested reader can purchase the full texts for the papers from the linked abstract pages). However, I don’t think that matters that much because the main point of this list really is to show that the basic research on the subject exists. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

UPDATE (September 23, 2012): Burch & Gryvnak (1966) added.
UPDATE (February 6, 2011): Miller & Watts (1984) added.
UPDATE (July 25, 2010): I modified the introduction paragraph a little to reflect the current content of the list. The old text was a little outdated.
UPDATE (June 22, 2010): Lecher & Pernter (1881) added.
UPDATE (March 31, 2010): Tubbs & Williams (1972), Rubens & Aschkinass (1898) and Ångström (1900) added.
UPDATE (March 6, 2010): Barker (1922) added.
UPDATE (November 19, 2009): Predoi-Cross et al. (2007) added.
UPDATE (September 25, 2009): Miller & Brown (2004) added, thanks to John Cook for bringing it to my attention (see the discussion section below).

Spectroscopic database of CO2 line parameters: 4300–7000 cm−1 – Toth et al. (2008) “A new spectroscopic database for carbon dioxide in the near infrared is presented to support remote sensing of the terrestrial planets (Mars, Venus and the Earth). The compilation contains over 28,500 transitions of 210 bands from 4300 to 7000 cm−1…”

Line shape parameters measurement and computations for self-broadened carbon dioxide transitions in the 30012 ← 00001 and 30013 ← 00001 bands, line mixing, and speed dependence – Predoi-Cross et al. (2007) “Transitions of pure carbon dioxide have been measured using a Fourier transform spectrometer in the 30012 ← 00001 and 30013 ← 00001 vibrational bands. The room temperature spectra, recorded at a resolution of 0.008 cm−1, were analyzed using the Voigt model and a Speed Dependent Voigt line shape model that includes a pressure dependent narrowing parameter. Intensities, self-induced pressure broadening, shifts, and weak line mixing coefficients are determined. The results obtained are consistent with other studies in addition to the theoretically calculated values.” [Full text]

Spectroscopic challenges for high accuracy retrievals of atmospheric CO2 and the Orbiting Carbon Observatory (OCO) experiment – Miller et al. (2005) “The space-based Orbiting Carbon Observatory (OCO) mission will achieve global measurements needed to distinguish spatial and temporal gradients in the CO2 column. Scheduled by NASA to launch in 2008, the instrument will obtain averaged dry air mole fraction (XCO2) with a precision of 1 part per million (0.3%) in order to quantify the variation of CO2 sources and sinks and to improve future climate forecasts. Retrievals of XCO2 from ground-based measurements require even higher precisions to validate the satellite data and link them accurately and without bias to the World Meteorological Organization (WMO) standard for atmospheric CO2 observations. These retrievals will require CO2 spectroscopic parameters with unprecedented accuracy. Here we present the experimental and data analysis methods implemented in laboratory studies in order to achieve this challenging goal.”

Near infrared spectroscopy of carbon dioxide I. 16O12C16O line positions – Miller & Brown (2004) “High-resolution near-infrared (4000–9000 cm-1) spectra of carbon dioxide have been recorded using the McMath–Pierce Fourier transform spectrometer at the Kitt Peak National Solar Observatory. Some 2500 observed positions have been used to determine spectroscopic constants for 53 different vibrational states of the 16O12C16O isotopologue, including eight vibrational states for which laboratory spectra have not previously been reported. … This work reduces CO2 near-infrared line position uncertainties by a factor of 10 or more compared to the 2000 HITRAN line list, which has not been modified since the comprehensive work of Rothman et al. [J. Quant. Spectrosc. Rad. Transfer 48 (1992) 537].” [Full text]

Spectra calculations in central and wing regions of CO2 IR bands between 10 and 20 μm. I: model and laboratory measurements – Niro et al. (2004) “Temperature (200–300 K) and pressure (70–200 atm) dependent laboratory measurements of infrared transmission by CO2–N2 mixtures have been made. From these experiments the absorption coefficient is reconstructed, over a range of several orders of magnitude, between 600 and 1000 cm−1.”

Collisional effects on spectral line-shapes – Boulet (2004) “The growing concern of mankind for the understanding and preserving of its environment has stimulated great interest for the study of planetary atmospheres and, first of all, for that of the Earth. Onboard spectrometers now provide more and more precise information on the transmission and emission of radiation by these atmospheres. Its treatment by ‘retrieval’ technics, in order to extract vertical profiles (pressure, temperature, volume mixing ratios) requires precise modeling of infrared absorption spectra. Within this framework, accounting for the influence of pressure on the absorption shape is crucial. These effects of inter-molecular collisions between the optically active species and the ‘perturbers’ are complex and of various types depending mostly on the density of perturbers. The present paper attempts to review and illustrate, through a few examples, the state of the art in this field.”

On far-wing Raman profiles by CO2 – Benech et al. (2002) “Despite the excellent agreement observed in N2 here, a substantial inconsistency between theory and experiment was found in the wing of the spectrum. Although the influence of other missing processes or neighboring bands cannot be totally excluded, our findings rather suggest that highly anisotropic perturbers, such as CO2, are improperly described when they are handled as point-like molecules, a cornerstone hypothesis in the approach employed.”

Collision-induced scattering in CO2 gas – Teboul et al. (1995) “Carbon-dioxide gas rototranslational scattering has been measured at 294.5 K in the frequency range 10–1000 cm−1 at 23 amagat. The depolarization ratio of scattered intensities in the frequency range 10–1000 cm−1 is recorded. The theoretical and experimental spectra in the frequency range 10–470 cm−1 are compared.”

The HITRAN database: 1986 edition – Rothman et al. (1987) “A description and summary of the latest edition of the AFGL HITRAN molecular absorption parameters database are presented. This new database combines the information for the seven principal atmospheric absorbers and twenty-one additional molecular species previously contained on the AFGL atmospheric absorption line parameter compilation and on the trace gas compilation.”

Rotational structure in the infrared spectra of carbon dioxide and nitrous oxide dimers – Miller & Watts (1984) “High-resolution infrared predissociation spectra have been measured for dilute mixtures of CO2 and N2O in helium. Rotational fine structure is clearly resolved for both (CO2)2 and (N2O)2, the linewidths being instrument-limited. This establishes that predissociation lifetimes are longer than approximately 50 ns.”

Broadening of Infrared Absorption Lines at Reduced Temperatures: Carbon Dioxide – Tubbs & Williams (1972) “An evacuated high-resolution Czerny-Turner spectrograph, which is described in this paper, has been used to determine the strengths S and self-broadening parameters γ0 for lines in the R branch of the ν3 fundamental of 12C16O2 at 298 and at 207 K. The values of γ0 at 207 K are greater than those to be expected on the basis of a fixed collision cross section σ.”

Investigation of the Absorption of Infrared Radiation by Atmospheric Gases – Burch et al. (1970) “From spectral transmittance curves of very large samples of CO2 we have determined coefficients for intrinsic absorption and pressure-induced absorption from approximately 1130/cm to 1835/cm.”

Absorption of Infrared Radiant Energy by CO2 and H2O. IV. Shapes of Collision-Broadened CO2 Lines – Burch et al. (1969) “The shapes of the extreme wings of self-broadened CO2 lines have been investigated in three spectral regions near 7000, 3800, and 2400 cm−1. … New information has been obtained about the shapes of self-broadened CO2 lines as well as CO2 lines broadened by N2, O2, Ar, He, and H2.”

High-Temperature Spectral Emissivities and Total Intensities of the 15-µ Band System of CO2 – Ludwig et al. (1966) “Spectral-emissivity measurements of the 15-µ band of CO2 were made in the temperature range from 1000° to 2300°K.”

Laboratory investigation of the absorption and emission of infrared radiation – Burch & Gryvnak (1966) “Extensive measurements of the absorption by H2O and CO2 have been made in the region from 0·6 to 5·5 microm. Two different multiple-pass absorption cells provided path lengths from 2 to 933 m, and sample pressures were varied from a few μHg to 15 atm. Approximately thirty new CO2 bands were observed and identified, and the strengths of the important bands determined. The H2O data provide enough information for the determination of the strengths and widths of several hundred of the more important lines. The wings of CO2absorption lines were found to be sub-Lorentzian, with the shapes depending on temperature, broadening gas, and wavelength in ways which cannot be explained by present theories. The absorption by H2O and CO2 samples at temperatures up to 1800°K has been studied from 1 to 5 microm. The transmission of radiation from hot CO2 through cold CO2 and from hot H2O through cold H2O has been investigated to determine the effect of the coincidence of emission lines with absorption lines.” Darrell E. Burch, David A. Gryvnak, Journal of Quantitative Spectroscopy and Radiative Transfer, Volume 6, Issue 3, May–June 1966, Pages 229–240,

Line shape in the wing beyond the band head of the 4·3 μ band of CO2 – Winters et al. (1964) “Quantitative absorpance measurements have been made in pure CO2 and mixtures of CO2 with N2 and O2 in a 10 m White Perkin-Elmer cell. With absorbing paths up to 50 m-atm, results have been obtained from the band head at 2397 cm−1 to 2575 cm−1.”

Emissivity of Carbon Dioxide at 4.3 µ – Davies (1964) “The emissivity of carbon dioxide has been measured for temperatures from 1500° to 3000°K over the wavelength range from 4.40 to 5.30 µ.”

Absorption Line Broadening in the Infrared – Burch et al. (1962) “The effects of various gases on the absorption bands of nitrous oxide, carbon monoxide, methane, carbon dioxide, and water vapor have been investigated.”

Total Absorptance of Carbon Dioxide in the Infrared – Burch et al. (1962) “Total absorptance… has been determined as a function of absorber concentration w and equivalent pressure Pe for the major infrared absorption bands of carbon dioxide with centers at 3716, 3609, 2350, 1064, and 961 cm−1.”

Rotation-Vibration Spectra of Diatomic and Simple Polyatomic Molecules with Long Absorbing Paths – Herzberg & Herzberg (1953) “The spectrum of CO2 in the photographic infrared has been studied with absorbing paths up to 5500 m. Thirteen absorption bands were found of which eleven have been analyzed in detail.”

The Infrared Absorption Spectrum of Carbon Dioxide – Martin & Barker (1932) “The complete infrared spectrum of CO2 may consistently be explained in terms of a linear symmetrical model, making use of the selection rules developed by Dennison and the resonance interaction introduced by Fermi. The inactive fundamental ν1 appears only in combination bands, but ν2 at 15μ and ν3 at 4.3μ absorb intensely.”

Carbon Dioxide Absorption in the Near Infra-Red – Barker (1922) “Infra-red absorption bands of CO2 at 2.7 and 4.3 μ. – New absorption curves have been obtained, using a special prism-grating double spectrometer of higher resolution (Figs. 1-3). The 2.7 μ region, heretofore considered to be a doublet, proves to be a pair of doublets, with centers at approximately 2.694 μ and 2.767 μ. The 4.3 μ band appears as a single doublet with center at 4.253 μ. The frequency difference between maxima is nearly the same for each of the three doublets, and equal to 4.5 x 1011. Complete resolution of the band series was not effected, even though the slit included only 12 A for the 2.7 μ region, but there is evidently a complicated structure, with a “head” in each case on the side of shorter wave-lengths. The existence of this head for the 4.3 μ band is also indicated by a comparison with the emission spectrum from a bunsen flame, and the difference in wave-length of the maxima of emission and absorption is explained as a temperature effect similar to that observed with other doublets.” [For free full text, click PDF or GIF links in the linked abstract page]

Ueber die Bedeutung des Wasserdampfes und der Kohlensäure bei der Absorption der Erdatmosphäre – Ångström (1900)

Observations on the Absorption and Emission of Aqueous Vapor and Carbon Dioxide in the Infra-Red Spectrum – Rubens & Aschkinass (1898) “Our experiments carried out as described above on the absorption spectrum carbon dioxide very soon showed that we were dealing with a single absorption band whose maximum lies near λ = 14.7 μ. … The whole region of absorption is limited to the interval from 12.5 μ to 16 μ, with the maximum at 14.7 μ.” [For free full text, click PDF or GIF links in the linked abstract page]

On the absorption of dark heat-rays by gases and vapours – Lecher & Pernter (1881) Svante Arrhenius wrote in his famous 1897 paper: “Tyndall held the opinion that the water-vapour has the greatest influence, whilst other authors, for instance Lecher and Pernter, are inclined to think that the carbonic acid plays the more important part.”.

The Bakerian Lecture – On the Absorption and Radiation of Heat by Gases and Vapours, and on the Physical Connexion of Radiation, Absorption, and Conduction – Tyndall (1861) 150 years ago John Tyndall already showed that carbon dioxide absorbs infrared radiation. [Full text] [Wikipedia: John Tyndall]

Closely related

The HITRAN Database – The laboratory work results on the absorption properties of carbon dioxide (and many other molecules) is contained in this database.

Posted in AGW evidence | 28 Comments »

Papers on ocean acidification

Posted by Ari Jokimäki on September 23, 2009

This is a list of papers on ocean acidification with emphasis on reduction of ocean pH due to rising atmospheric carbon dioxide concentration. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

UPDATE (November 16, 2012): Byrne et al. (2010) and Bates et al. (2012) added.
UPDATE (September 13, 2010): Feely et al. (2008) added.
UPDATE (April 7, 2010): Pelejero et al. (2010) added.

Detecting anthropogenic carbon dioxide uptake and ocean acidification in the North Atlantic Ocean – Bates et al. (2012) “Fossil fuel use, cement manufacture and land-use changes are the primary sources of anthropogenic carbon dioxide (CO2) to the atmosphere, with the ocean absorbing approximately 30% (Sabine et al., 2004). Ocean uptake and chemical equilibration of anthropogenic CO2 with seawater results in a gradual reduction in seawater pH and saturation states (Ω) for calcium carbonate (CaCO3) minerals in a process termed ocean acidification. Assessing the present and future impact of ocean acidification on marine ecosystems requires detection of the multi-decadal rate of change across ocean basins and at ocean time-series sites. Here, we show the longest continuous record of ocean CO2 changes and ocean acidification in the North Atlantic subtropical gyre near Bermuda from 1983–2011. Dissolved inorganic carbon (DIC) and partial pressure of CO2 (pCO2) increased in surface seawater by ~40 μmol kg−1 and ~50 μatm (~20%), respectively. Increasing Revelle factor (β) values imply that the capacity of North Atlantic surface waters to absorb CO2 has also diminished. As indicators of ocean acidification, seawater pH decreased by ~0.05 (0.0017 yr−1) and ω values by ~7–8%. Such data provide critically needed multi-decadal information for assessing the North Atlantic Ocean CO2 sink and the pH changes that determine marine ecosystem responses to ocean acidification.” Bates, N. R., Best, M. H. P., Neely, K., Garley, R., Dickson, A. G., and Johnson, R. J.: Detecting anthropogenic carbon dioxide uptake and ocean acidification in the North Atlantic Ocean, Biogeosciences, 9, 2509-2522, doi:10.5194/bg-9-2509-2012, 2012. [Full text]

Paleo-perspectives on ocean acidification – Pelejero et al. (2010) “The anthropogenic rise in atmospheric CO2 is driving fundamental and unprecedented changes in the chemistry of the oceans. This has led to changes in the physiology of a wide variety of marine organisms and, consequently, the ecology of the ocean. This review explores recent advances in our understanding of ocean acidification with a particular emphasis on past changes to ocean chemistry and what they can tell us about present and future changes. We argue that ocean conditions are already more extreme than those experienced by marine organisms and ecosystems for millions of years, emphasising the urgent need to adopt policies that drastically reduce CO2 emissions.” Carles Pelejero, Eva Calvo, Ove Hoegh-Guldberg, Trends in Ecology & Evolution, Volume 25, Issue 6, 332-344, 30 March 2010, DOI: 10.1016/j.tree.2010.02.002. [Full text, John Cook’s article on this paper]

Direct observations of basin-wide acidification of the North Pacific Ocean – Byrne et al. (2010) “Global ocean acidification is a prominent, inexorable change associated with rising levels of atmospheric CO2. Here we present the first basin-wide direct observations of recently declining pH, along with estimates of anthropogenic and non-anthropogenic contributions to that signal. Along 152°W in the North Pacific Ocean (22–56°N), pH changes between 1991 and 2006 were essentially zero below about 800 m depth. However, in the upper 500 m, significant pH changes, as large as −0.06, were observed. Anthropogenic and non-anthropogenic contributions over the upper 800 m are estimated to be of similar magnitude. In the surface mixed layer (depths to ∼100 m), the extent of pH change is consistent with that expected under conditions of seawater/atmosphere equilibration, with an average rate of change of −0.0017/yr. Future mixed layer changes can be expected to closely mirror changes in atmospheric CO2, with surface seawater pH continuing to fall as atmospheric CO2 rises.” Byrne, R. H., S. Mecking, R. A. Feely, and X. Liu (2010), Direct observations of basin-wide acidification of the North Pacific Ocean, Geophys. Res. Lett., 37, L02601, doi:10.1029/2009GL040999. [Full text]

Physical and biogeochemical modulation of ocean acidification in the central North Pacific – Dore et al. (2009) “Here we report the results of nearly 20 years of time-series measurements of seawater pH and associated parameters at Station ALOHA in the central North Pacific Ocean near Hawaii. We document a significant long-term decreasing trend of −0.0019 ± 0.0002 y−1 in surface pH, which is indistinguishable from the rate of acidification expected from equilibration with the atmosphere.” [Full text]

Ocean Acidification: The Other CO2 Problem – Doney et al. (2009) A review paper. “Rising atmospheric carbon dioxide (CO2), primarily from human fossil fuel combustion, reduces ocean pH and causes wholesale shifts in seawater carbonate chemistry. The process of ocean acidification is well documented in field data, and the rate will accelerate over this century unless future CO2 emissions are curbed dramatically. Acidification alters seawater chemical speciation and biogeochemical cycles of many elements and compounds. One well-known effect is the lowering of calcium carbonate saturation states, which impacts shell-forming marine organisms from plankton to benthic molluscs, echinoderms, and corals.” [Full text]

Dynamic patterns and ecological impacts of declining ocean pH in a high-resolution multi-year dataset – Wootton et al. (2008) “In a high-resolution dataset spanning 8 years, pH at a north-temperate coastal site declined with increasing atmospheric CO2 levels and varied substantially in response to biological processes and physical conditions that fluctuate over multiple time scales.” [Full text]

Evidence for Upwelling of Corrosive “Acidified” Water onto the Continental Shelf – Feely et al. (2008) “The absorption of atmospheric carbon dioxide (CO2) into the ocean lowers the pH of the waters. This so-called ocean acidification could have important consequences for marine ecosystems. To better understand the extent of this ocean acidification in coastal waters, we conducted hydrographic surveys along the continental shelf of western North America from central Canada to northern Mexico. We observed seawater that is undersaturated with respect to aragonite upwelling onto large portions of the continental shelf, reaching depths of 40 to 120 meters along most transect lines and all the way to the surface on one transect off northern California. Although seasonal upwelling of the undersaturated waters onto the shelf is a natural phenomenon in this region, the ocean uptake of anthropogenic CO2 has increased the areal extent of the affected area.” Richard A. Feely, Christopher L. Sabine, J. Martin Hernandez-Ayon, Debby Ianson, Burke Hales, Science 13 June 2008: Vol. 320. no. 5882, pp. 1490 – 1492, DOI: 10.1126/science.1155676. [Full text]

Southern Ocean acidification: A tipping point at 450-ppm atmospheric CO2 – McNeil & Matear (2008) “We present a large-scale Southern Ocean observational analysis that examines the seasonal magnitude and variability of CO32− and pH. Our analysis shows an intense wintertime minimum in CO32− south of the Antarctic Polar Front and when combined with anthropogenic CO2 uptake is likely to induce aragonite undersaturation when atmospheric CO2 levels reach ≈450 ppm.” [Full text]

pH variability and CO2 induced acidification in the North Sea – Blackford & Gilbert (2007) A model study. “Annual pH ranges are found to vary from 1.0 in areas influenced by riverine signals, consistent with observations and previous studies. It is shown that benthic, as well as pelagic, activity is an important factor in this variability. The acidification of the region due to increased fluxes of atmospheric CO2 into the marine system is calculated and shown to exceed, on average, 0.1 pH units over the next 50 years and result in a total acidification of 0.5 pH units below pre-industrial levels at atmospheric CO2 concentrations of 1000 ppm.”

The interannual variability of oceanic CO2 parameters in the northeast Atlantic subtropical gyre at the ESTOC site – Santana-Casiano et al. (2007) Reports pH measurements (among other parameters) from a single location. “Our series of experimental pHT data confirm the acidification of surface waters in the east Atlantic Ocean, with an interannual decrease of 0.0017 ± 0.0004 pH units yr−1.” [Full text]

Interannual variability of the oceanic CO2 sink in the subtropical gyre of the North Atlantic Ocean over the last 2 decades – Bates (2007) While concentrating on oceanic CO2 sink measurements, reports pH measurements from a single location. “In addition, seawater pH, CO32- ion concentrations, and CaCO3 saturation states have also decreased over time.” [Full text]

Experimental measurement of boron isotope fractionation in seawater – Klochko et al. (2006) “The boron isotopic composition of marine carbonates is considered to be a tracer of seawater pH. Use of this proxy benefits from an intimate understanding of chemical kinetics and thermodynamic isotope exchange reactions between the two dominant boron-bearing species in seawater: boric acid B(OH)3 and borate ion B(OH)4. However, because of our inability to quantitatively separate these species in solution, the degree of boron isotope exchange has only been known through theoretical estimates. In this study, we present results of a spectrophotometric procedure wherein the boron isotope equilibrium constant (11–10KB) is determined empirically” [Full text]

Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms – Orr et al. (2005) A model study. “Here we use 13 models of the ocean–carbon cycle to assess calcium carbonate saturation under the IS92a ‘business-as-usual’ scenario for future emissions of anthropogenic carbon dioxide. … Our findings indicate that conditions detrimental to high-latitude ecosystems could develop within decades, not centuries as suggested previously.” [Full text]

Ocean acidification due to increasing atmospheric carbon dioxide – Raven et al. (2005) The Royal Society report. “Evidence indicates that emissions of carbon dioxide from human activities over the past 200 years have already led to a reduction in the average pH of surface seawater of 0.1 units and could fall by 0.5 units by the year 2100. This pH is probably lower than has been experienced for hundreds of millennia and, critically, at a rate of change probably 100 times greater than at any time over this period.” [Full text]

Impact of Anthropogenic CO2 on the CaCO3 System in the Oceans – Feely et al. (2004) “Here we estimate the in situ CaCO3 dissolution rates for the global oceans from total alkalinity and chlorofluorocarbon data, and we also discuss the future impacts of anthropogenic CO2 on CaCO3 shell–forming species. CaCO3 dissolution rates, ranging from 0.003 to 1.2 micromoles per kilogram per year, are observed beginning near the aragonite saturation horizon.” [Full text]

Anthropogenic carbon and ocean pH – Caldeira & Wickett (2003) A model study. “Here we quantify the changes in ocean pH that may result from this continued release of CO2 and compare these with pH changes estimated from geological and historical records. We find that oceanic absorption of CO2 from fossil fuels may result in larger pH changes over the next several centuries than any inferred from the geological record of the past 300 million years, with the possible exception of those resulting from rare, extreme events such as bolide impacts or catastrophic methane hydrate degassing.” [Full text]

The role of pHT measurements in marine CO2-system characterizations – Byrne et al. (1999) “In this work, using the NOAA 1992 boreal autumn Equatorial Pacific (EqPac) dataset, it is shown that CO2-system variables calculated via pHT can be used to enhance both the precision and accuracy of directly measured parameters. Through the procedures described in this work significant problems were revealed in the initial version of the 1992 NOAA dataset, and the dataset was greatly improved.”

The role of pH measurements in modern oceanic CO2-system characterizations: Precision and thermodynamic consistency – Clayton et al. (1995) “In May 1992, surface seawater samples were collected along an equatorial transit (130 to 100°W) and analyzed for total hydrogen ion concentration (expressed as spectrophotometric pHT) total dissolved inorganic carbon (coulometric CT), and total alkalinity (potentiometric AT and spectrophotometric AT). … In light of recent advances, the role of pH measurements in CO2-system characterizations should be re-evaluated. Spectrophotometric measurements of pH have much to contribute in documenting the oceans’ evolving response to anthropogenic C02.”

Closely related

Ocean acidification – A blog devoted to the subject.

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Papers on global surface temperature

Posted by Ari Jokimäki on September 21, 2009

This is a list of papers on surface temperature measurements of the Earth with emphasis on global analysis. Reconstructions are not included. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

There is also a special list: Papers on global surface temperature since 1998.

UPDATE (August 15, 2013): Thorne et al. (2011) added.
UPDATE (August 6, 2013): Köppen (1881), Callendar (1938), and Hawkins & Jones (2013) added. Thanks to Ed Hawkins for pointing them out.
UPDATE (May 8, 2012): Willett (1950), Mitchell (1961), Callendar (1961), Brinkmann (1976), and Jones et al. (1982) added.
UPDATE (April 17, 2012): Morice et al. (2012) added. Thanks to Barry for pointing it out.
UPDATE (April 5, 2010): Menne et al. (2010) and Hansen et al. (2010) added. Full text link was added to Jones et al. (1999), Folland et al. (2001).

On increasing global temperatures: 75 years after Callendar – Hawkins & Jones (2013) “In 1938, Guy Stewart Callendar was the first to demonstrate that the Earth’s land surface was warming. Callendar also suggested that the production of carbon dioxide by the combustion of fossil fuels was responsible for much of this modern change in climate. This short note marks the 75th anniversary of Callendar’s landmark study and demonstrates that his global land temperature estimates agree remarkably well with more recent analyses.” Ed Hawkins, Phil. D. Jones, Quarterly Journal of the Royal Meteorological Society, DOI: 10.1002/qj.2178. [Full text]

Quantifying uncertainties in global and regional temperature change using an ensemble of observational estimates: The HadCRUT4 data set – Morice et al. (2012) “Recent developments in observational near-surface air temperature and sea-surface temperature analyses are combined to produce HadCRUT4, a new data set of global and regional temperature evolution from 1850 to the present. This includes the addition of newly digitized measurement data, both over land and sea, new sea-surface temperature bias adjustments and a more comprehensive error model for describing uncertainties in sea-surface temperature measurements. An ensemble approach has been adopted to better describe complex temporal and spatial interdependencies of measurement and bias uncertainties and to allow these correlated uncertainties to be taken into account in studies that are based upon HadCRUT4. Climate diagnostics computed from the gridded data set broadly agree with those of other global near-surface temperature analyses. Fitted linear trends in temperature anomalies are approximately 0.07°C/decade from 1901 to 2010 and 0.17°C/decade from 1979 to 2010 globally. Northern/southern hemispheric trends are 0.08/0.07°C/decade over 1901 to 2010 and 0.24/0.10°C/decade over 1979 to 2010. Linear trends in other prominent near-surface temperature analyses agree well with the range of trends computed from the HadCRUT4 ensemble members.” Morice, C. P., J. J. Kennedy, N. A. Rayner, and P. D. Jones (2012), Quantifying uncertainties in global and regional temperature change using an ensemble of observational estimates: The HadCRUT4 data set, J. Geophys. Res., 117, D08101, doi:10.1029/2011JD017187. [Full text]

Guiding the Creation of A Comprehensive Surface Temperature Resource for Twenty-First-Century Climate Science – Thorne et al. (2011) No abstract, a meeting summary. Thorne, Peter W., and Coauthors, 2011: Guiding the Creation of A Comprehensive Surface Temperature Resource for Twenty-First-Century Climate Science. Bull. Amer. Meteor. Soc., 92, ES40–ES47. doi: [Full text]

Global surface temperature change – Hansen et al. (2010) “We update the Goddard Institute for Space Studies (GISS) analysis of global surface temperature change, compare alternative analyses, and address questions about perception and reality of global warming. Satellite-observed night lights are used to identify measurement stations located in extreme darkness and adjust temperature trends of urban and periurban stations for nonclimatic factors, verifying that urban effects on analyzed global change are small. Because the GISS analysis combines available sea surface temperature records with meteorological station measurements, we test alternative choices for the ocean data, showing that global temperature change is sensitive to estimated temperature change in polar regions where observations are limited. We use simple 12 month (and n × 12) running means to improve the information content in our temperature graphs. Contrary to a popular misconception, the rate of warming has not declined. Global temperature is rising as fast in the past decade as in the prior 2 decades, despite year-to-year fluctuations associated with the El Niño-La Niña cycle of tropical ocean temperature. Record high global 12 month running mean temperature for the period with instrumental data was reached in 2010.” Hansen, J., R. Ruedy, M. Sato, and K. Lo (2010), Rev. Geophys., 48, RG4004, doi:10.1029/2010RG000345. [Full text]

On the reliability of the U.S. Surface Temperature Record – Menne et al. (2010) “Recent photographic documentation of poor siting conditions at stations in the U.S. Historical Climatology Network (USHCN) has led to questions regarding the reliability of surface temperature trends over the conterminous U.S. (CONUS). To evaluate the potential impact of poor siting/instrument exposure on CONUS temperatures, trends derived from poor and well-sited USHCN stations were compared. Results indicate that there is a mean bias associated with poor exposure sites relative to good exposure sites; however, this bias is consistent with previously documented changes associated with the widespread conversion to electronic sensors in the USHCN during the last 25 years. Moreover, the sign of the bias is counterintuitive to photographic documentation of poor exposure because associated instrument changes have led to an artificial negative (“cool”) bias in maximum temperatures and only a slight positive (“warm”) bias in minimum temperatures. … Adjustments applied to USHCN Version 2 data largely account for the impact of instrument and siting changes, although a small overall residual negative (“cool”) bias appears to remain in the adjusted maximum temperature series. Nevertheless, the adjusted USHCN temperatures are extremely well aligned with recent measurements from instruments whose exposure characteristics meet the highest standards for climate monitoring. In summary, we find no evidence that the CONUS temperature trends are inflated due to poor station siting.” Menne, M. J., C. N. Williams Jr., and M. A. Palecki (2010), On the reliability of the U.S. surface temperature record, J. Geophys. Res., 115, D11108, doi:10.1029/2009JD013094. [Full text]

A large discontinuity in the mid-twentieth century in observed global-mean surface temperature – Thompson et al. (2008) “Data sets used to monitor the Earth’s climate indicate that the surface of the Earth warmed from ~ 1910 to 1940, cooled slightly from ~ 1940 to 1970, and then warmed markedly from ~ 1970 onward. The weak cooling apparent in the middle part of the century has been interpreted in the context of a variety of physical factors, such as atmosphere–ocean interactions and anthropogenic emissions of sulphate aerosols. Here we call attention to a previously overlooked discontinuity in the record at 1945, which is a prominent feature of the cooling trend in the mid-twentieth century. The discontinuity is evident in published versions of the global-mean temperature time series, but stands out more clearly after the data are filtered for the effects of internal climate variability. We argue that the abrupt temperature drop of ~0.3 °C in 1945 is the apparent result of uncorrected instrumental biases in the sea surface temperature record. Corrections for the discontinuity are expected to alter the character of mid-twentieth century temperature variability but not estimates of the century-long trend in global-mean temperatures.” David W. J. Thompson, John J. Kennedy, John M. Wallace & Phil D. Jones, Nature 453, 646-649 (29 May 2008), doi:10.1038/nature06982 [Full text]

Improvements to NOAA’s Historical Merged Land–Ocean Surface Temperature Analysis (1880–2006) – Smith et al. (2008) “Observations of sea surface and land–near-surface merged temperature anomalies are used to monitor climate variations and to evaluate climate simulations; therefore, it is important to make analyses of these data as accurate as possible. Analysis uncertainty occurs because of data errors and incomplete sampling over the historical period. This manuscript documents recent improvements in NOAA’s merged global surface temperature anomaly analysis, monthly, in spatial 5° grid boxes. These improvements allow better analysis of temperatures throughout the record, with the greatest improvements in the late nineteenth century and since 1985. Improvements in the late nineteenth century are due to improved tuning of the analysis methods. Beginning in 1985, improvements are due to the inclusion of bias-adjusted satellite data. The old analysis (version 2) was documented in 2005, and this improved analysis is called version 3.” Smith, Thomas M., Richard W. Reynolds, Thomas C. Peterson, Jay Lawrimore, 2008: Improvements to NOAA’s Historical Merged Land–Ocean Surface Temperature Analysis (1880–2006). J. Climate, 21, 2283–2296. doi: [Full text]

Uncertainty estimates in regional and global observed temperature changes: A new data set from 1850 – Brohan et al. (2006) “The historical surface temperature data set HadCRUT provides a record of surface temperature trends and variability since 1850. A new version of this data set, HadCRUT3, has been produced, benefiting from recent improvements to the sea surface temperature data set which forms its marine component, and from improvements to the station records which provide the land data. A comprehensive set of uncertainty estimates has been derived to accompany the data: Estimates of measurement and sampling error, temperature bias effects, and the effect of limited observational coverage on large-scale averages have all been made. Since the mid twentieth century the uncertainties in global and hemispheric mean temperatures are small, and the temperature increase greatly exceeds its uncertainty. In earlier periods the uncertainties are larger, but the temperature increase over the twentieth century is still significantly larger than its uncertainty.” Brohan, P., J. J. Kennedy, I. Harris, S. F. B. Tett, and P. D. Jones (2006), Uncertainty estimates in regional and global observed temperature changes: A new data set from 1850, J. Geophys. Res., 111, D12106, doi:10.1029/2005JD006548. [Full text]

Hemispheric and Large-Scale Surface Air Temperature Variations: An Extensive Revision and an Update to 2001 – Jones & Moberg (2003) “This study is an extensive revision of the Climatic Research Unit (CRU) land station temperature database that is used to produce a gridbox dataset of 5° latitude × 5° longitude temperature anomalies. The new database comprises 5159 station records, of which 4167 have enough data for the 1961–90 period to calculate or estimate the necessary averages. Apart from the increase in station numbers compared to the earlier study in 1994, many station records have had their data replaced by newly homogenized series that have been produced by several recent studies. New versions of all the gridded datasets currently available on the CRU Web site ( have been developed. This includes combinations with marine (sea surface temperature anomalies) data over the oceans and versions with adjustment of the variance of individual gridbox series to remove the effects of changing station numbers through time. Hemispheric and global temperature averages for land areas developed with the new dataset differ slightly from those developed in 1994. Possible reasons for the differences between the new and the earlier analysis and those from the National Climatic Data Center and the Goddard Institute for Space Studies are discussed. Differences are greatest over the Southern Hemisphere and at the beginnings and ends of each time series and relate to gridbox sizes and data availability. The rate of annual warming for global land areas over the 1901–2000 period is estimated by least squares to be 0.07°C decade−1 (significant at better than the 99.9% level). Warming is not continuous but occurs principally over two periods (about 1920–45 and since 1975). Annual temperature series for the seven continents and the Arctic all show significant warming over the twentieth century, with significant (95%) warming for 1920–44 for North America, the Arctic, Africa, and South America, and all continents except Australia and the Antarctic since 1977. Cooling is significant during the intervening period (1945–76) for North America, the Arctic, and Africa.” Jones, P. D., A. Moberg, 2003: Hemispheric and Large-Scale Surface Air Temperature Variations: An Extensive Revision and an Update to 2001. J. Climate, 16, 206–223. doi:;2 [Full text]

A closer look at United States and global surface temperature change – Hansen et al. (2001) “We compare the United States and global surface air temperature changes of the past century using the current Goddard Institute for Space Studies (GISS) analysis and the U.S. Historical Climatology Network (USHCN) record [Karl et al., 1990]. Changes in the GISS analysis subsequent to the documentation by Hansen et al. [1999] are as follows: (1) incorporation of corrections for time-of-observation bias and station history adjustments in the United States based on Easterling et al. [1996a], (2) reclassification of rural, small-town, and urban stations in the United States, southern Canada, and northern Mexico based on satellite measurements of night light intensity [Imhoff et al., 1997], and (3) a more flexible urban adjustment than that employed by Hansen et al. [1999], including reliance on only unlit stations in the United States and rural stations in the rest of the world for determining long-term trends. We find evidence of local human effects (“urban warming”) even in suburban and small-town surface air temperature records, but the effect is modest in magnitude and conceivably could be an artifact of inhomogeneities in the station records. We suggest further studies, including more complete satellite night light analyses, which may clarify the potential urban effect. There are inherent uncertainties in the long-term temperature change at least of the order of 0.1°C for both the U.S. mean and the global mean. Nevertheless, it is clear that the post-1930s cooling was much larger in the United States than in the global mean. The U.S. mean temperature has now reached a level comparable to that of the 1930s, while the global temperature is now far above the levels earlier in the century. The successive periods of global warming (1900–1940), cooling (1940–1965), and warming (1965–2000) in the 20th century show distinctive patterns of temperature change suggestive of roles for both climate forcings and dynamical variability. The U.S. was warm in 2000 but cooler than the warmest years in the 1930s and 1990s. Global temperature was moderately high in 2000 despite a lingering La Niña in the Pacific Ocean.” Hansen, J., R. Ruedy, M. Sato, M. Imhoff, W. Lawrence, D. Easterling, T. Peterson, and T. Karl (2001), A closer look at United States and global surface temperature change, J. Geophys. Res., 106, 23,947–23,963, doi:10.1029/2001JD000354. [Full text]

Global temperature change and its uncertainties since 1861 – Folland et al. (2001) “We present the first analysis of global and hemispheric surface warming trends that attempts to quantify the major sources of uncertainty. We calculate global and hemispheric annual temperature anomalies by combining land surface air temperature and sea surface temperature (SST) through an optimal averaging technique. The technique allows estimation of uncertainties in the annual anomalies resulting from data gaps and random errors. We add independent uncertainties due to urbanisation, changing land‐based observing practices and SST bias corrections. We test the accuracy of the SST bias corrections, which represent the largest source of uncertainty in the data, through a suite of climate model simulations. These indicate that the corrections are likely to be fairly accurate on an annual average and on large space scales. Allowing for serial correlation and annual uncertainties, the best linear fit to annual global surface temperature gives an increase of 0.61±0.16°C between 1861 and 2000.” Folland, C. K., et al. (2001), Global temperature change and its uncertainties since 1861, Geophys. Res. Lett., 28(13), 2621–2624, doi:10.1029/2001GL012877. [Full text]

GISS analysis of surface temperature change – Hansen et al. (1999) “We describe the current GISS analysis of surface temperature change for the period 1880–1999 based primarily on meteorological station measurements. The global surface temperature in 1998 was the warmest in the period of instrumental data. The rate of temperature change was higher in the past 25 years than at any previous time in the period of instrumental data. The warmth of 1998 was too large and pervasive to be fully accounted for by the recent El Nino. Despite cooling in the first half of 1999, we suggest that the mean global temperature, averaged over 2–3 years, has moved to a higher level, analogous to the increase that occurred in the late 1970s. Warming in the United States over the past 50 years has been smaller than in most of the world, and over that period there was a slight cooling trend in the eastern United States and the neighboring Atlantic Ocean. The spatial and temporal patterns of the temperature change suggest that more than one mechanism was involved in this regional cooling. The cooling trend in the United States, which began after the 1930s and is associated with ocean temperature change patterns, began to reverse after 1979. We suggest that further warming in the United States to a level rivaling the 1930s is likely in the next decade, but reliable prediction requires better understanding of decadal oscillations of ocean temperature.” Hansen, J., R. Ruedy, J. Glascoe, and M. Sato (1999), GISS analysis of surface temperature change, J. Geophys. Res., 104(D24), 30,997–31,022, doi:10.1029/1999JD900835. [Full text, file size is over 15 MB]

Surface Air Temperature and its Changes Over the Past 150 Years – Jones et al. (1999) “We review the surface air temperature record of the past 150 years, considering the homogeneity of the basic data and the standard errors of estimation of the average hemispheric and global estimates. We present global fields of surface temperature change over the two 20-year periods of greatest warming this century, 1925–1944 and 1978–1997. Over these periods, global temperatures rose by 0.37° and 0.32°C, respectively. The twentieth-century warming has been accompanied by a decrease in those areas of the world affected by exceptionally cool temperatures and to a lesser extent by increases in areas affected by exceptionally warm temperatures. In recent decades there have been much greater increases in night minimum temperatures than in day maximum temperatures, so that over 1950–1993 the diurnal temperature range has decreased by 0.08°C per decade. We discuss the recent divergence of surface and satellite temperature measurements of the lower troposphere and consider the last 150 years in the context of the last millennium. We then provide a globally complete absolute surface air temperature climatology on a 1° × 1° grid. This is primarily based on data for 1961–1990. Extensive interpolation had to be undertaken over both polar regions and in a few other regions where basic data are scarce, but we believe the climatology is the most consistent and reliable of absolute surface air temperature conditions over the world. The climatology indicates that the annual average surface temperature of the world is 14.0°C (14.6°C in the Northern Hemisphere (NH) and 13.4°C for the Southern Hemisphere). The annual cycle of global mean temperatures follows that of the land-dominated NH, with a maximum in July of 15.9°C and a minimum in January of 12.2°C.” Jones, P. D., M. New, D. E. Parker, S. Martin, and I. G. Rigor (1999), Surface air temperature and its changes over the past 150 years, Rev. Geophys., 37(2), 173–199, doi:10.1029/1999RG900002. [Full text]

An Overview of the Global Historical Climatology Network Temperature Database – Peterson & Vose (1997) “The Global Historical Climatology Network version 2 temperature database was released in May 1997. This century-scale dataset consists of monthly surface observations from ~7000 stations from around the world. This archive breaks considerable new ground in the field of global climate databases. The enhancements include 1) data for additional stations to improve regional-scale analyses, particularly in previously data-sparse areas; 2) the addition of maximum–minimum temperature data to provide climate information not available in mean temperature data alone; 3) detailed assessments of data quality to increase the confidence in research results; 4) rigorous and objective homogeneity adjustments to decrease the effect of nonclimatic factors on the time series; 5) detailed metadata (e.g., population, vegetation, topography) that allow more detailed analyses to be conducted; and 6) an infrastructure for updating the archive at regular intervals so that current climatic conditions can constantly be put into historical perspective. This paper describes these enhancements in detail.” Peterson, Thomas C., Russell S. Vose, 1997: An Overview of the Global Historical Climatology Network Temperature Database. Bull. Amer. Meteor. Soc., 78, 2837–2849. doi:;2 [Full text]

Global Trends of Measured Surface Air Temperature – Hansen & Lebedeff (1987) “We analyze surface air temperature data from available meteorological stations with principal focus on the period 1880–1985. The temperature changes at mid- and high latitude stations separated by less than 1000 km are shown to be highly correlated; at low latitudes the correlation falls off more rapidly with distance for nearby stations. We combine the station data in a way which is designed to provide accurate long-term variations. Error estimates are based in part on studies of how accurately the actual station distributions are able to reproduce temperature change in a global data set produced by a three-dimensional general circulation model with realistic variability. We find that meaningful global temperature change can be obtained for the past century, despite the fact that the meteorological stations are confined mainly to continental and island locations. The results indicate a global warming of about 0.5°–0.7°C in the past century, with warming of similar magnitude in both hemispheres; the northern hemisphere result is similar to that found by several other investigators. A strong warming trend between 1965 and 1980 raised the global mean temperature in 1980 and 1981 to the highest level in the period of instrumental records. The warm period in recent years differs qualitatively from the earlier warm period centered about 1940; the earlier warming was focused at high northern latitudes, while the recent warming is more global. We present selected graphs and maps of the temperature change in each of the eight latitude zones. A computer tape of the derived regional and global temperature changes is available from the authors.” Hansen, J., and S. Lebedeff (1987), Global Trends of Measured Surface Air Temperature, J. Geophys. Res., 92(D11), 13,345–13,372, doi:10.1029/JD092iD11p13345. [Full text]

Variations in Surface Air Temperatures: Part 1. Northern Hemisphere, 1881–1980 – Jones et al. (1982) “We have produced, using objective techniques, a long-term series of average Northern Hemisphere temperatures based on monthly mean station data gridded on a 5° latitude by 10° longitude grid. Difficulties in the estimation of this parameter are discussed, deficiencies in the currently available data base and possible effects on the estimated average are described, and monthly mean data are presented. Long-term trends and extremes are identified in the annual and seasonal data. All seasons show similar long-term trends, but there are noticeable differences on time scales of 10 years and less. For example, for winter temperature, the early 20th century warming peaked during the 1940’s whereas the maximum in the other seasons was in the previous decade. Both the magnitude of the long-term trends and the year-to-year variability has been greatest in winter. There is evidence that the long-term cooling that characterized the 1940’s, 1950’s and 1960’s has ended. Warming began in the mid to late 1960’s in winter and spring, in the mid 1970’s in autumn and later in summer. Year-to-year variability has been particularly pronounced during the 1970’s. For example, 1972 was the coldest winter since 1918, yet 1980 and 1981 were among the five warmest winters during the last 100 years. There is, as yet, no statistical reason to associate the recent warming with atmospheric CO2 increases.” Jones, P. D., T. M. L. Wigley, P. M. Kelly, 1982: Variations in Surface Air Temperatures: Part 1. Northern Hemisphere, 1881–1980. Mon. Wea. Rev., 110, 59–70. doi:;2. [Full text]

Surface temperature trend for the Northern Hemisphere-updated – Brinkmann (1976) “The surface temperature curve for the Northern Hemisphere was extended to include the years 1969 through 1973 following the same procedure used by H. C. Willett, J. M. Mitchell, Jr., and C. H. Reitan. The analysis showed a slight warming of 0.02°C between the periods 1965–1969 and 1970–1973, and a significant decrease in the number of negative temperature changes at individual stations (indicating a decrease in the total area experiencing temperature decrease).” Waltraud A.R. Brinkmann, Quaternary Research, Volume 6, Issue 3, September 1976, Pages 355–358.

Temperature fluctuations and trends over the earth – Callendar (1961) “The annual temperature deviations at over 400 meteorological stations are combined on a regional basis to give the integrated fluctuations over large areas and zones. These are shown in graphical form, and it is concluded that a solar or atmospheric dust hypothesis is necessary to explain the world-wide fluctuations of a few years duration. An important change in the relationships of the zonal fluctuations has occurred since 1920. The overall temperature trends found from the data are considered in relation to the homogeneity of recording, and also to the evidence of glacial recession in different zones. It is concluded that the rising trend, shown by the instruments during recent decades, is significant from the Arctic to about 45°S lat., but quite small in most regions below 35°N. and not yet apparent in some. It is thought that the regional and zonal distribution of recent climatic trends is incompatible with the hypothesis of increased solar heating as the cause. On the other hand, the major features of this distribution are not incompatible with the hypothesis of increased carbon dioxide radiation, if the rate of atmospheric mixing between the hemispheres is a matter of decades rather than years.” G. S. Callendar, Quarterly Journal of the Royal Meteorological Society, Volume 87, Issue 371, pages 1–12, January 1961, DOI: 10.1002/qj.49708737102.

Recent secular changes of global temperature – Mitchell (1961) No abstract, quote from the introduction: “I took advantage of this opportunity to re-analyze Willett’s basic data, after updating it, in order to compare the zonally-averaged secular trends in the Northern and Southern Hemispheres and in the tropics during the past century. The purpose of this paper is to summarize the results of this re-analysis of updated global temperature data and to make a preliminary evaluation of their significance to extant quantitative theories of secular climatic change.” J. Murray Mitchell Jr., Annals of the New York Academy of Sciences, Volume 95, Solar Variatoins, Climatic Change, and Related Geophysical Problems, pages 235–250, October 1961, DOI: 10.1111/j.1749-6632.1961.tb50036.x.

Temperature trends in the past century – Willett (1950) Mentioned as one of early surface temperature analyses by Hansen & Lebedeff (1987). Willett, H. C., Centenary Proceedings of the Royal Meteorological Society, 195-206, 1950.

The artificial production of carbon dioxide and its influence on temperature – Callendar (1938) “By fuel combustion man has added about 150,000 million tons of carbon dioxide to the air during the past half century. The author estimates from the best available data that approximately three quarters of this has remained in the atmosphere. The radiation absorption coefficients of carbon dioxide and water vapour are used to show the effect of carbon dioxide on “sky radiation.” From this the increase in mean temperature, due to the artificial production of carbon dioxide, is estimated to be at the rate of 0.003°C. per year at the present time. The temperature observations at 200 meteorological stations are used to show that world temperatures have actually increased at an average rate of 0.005°C. per year during the past half century.” G. S. Callendar, Quarterly Journal of the Royal Meteorological Society, Volume 64, Issue 275, pages 223–240, April 1938, DOI: 10.1002/qj.49706427503. [Full text]

Über mehrjährige perioden der witterung–III. Mehrjährige änderungen der temperatur 1841 bis 1875 in den tropen der nördlichen und südlichen gemässigten zone, an den Jahresmitteln. untersucht. – Köppen (1881) This does not seem to be available online. Hawkins & Jones (2013) write: “Separately, widespread temperature records were being used to estimate the variability in global land air temperatures during the late 1800s (e.g. Köppen, 1881), but no trend was evident.” Köppen W. 1881, Zeitschrift der Österreichischen Gesellschaft für Meteorologie Bd XVI: 141–150.

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Papers on fossils revealed by melting glaciers

Posted by Ari Jokimäki on September 18, 2009

This is a list of papers on fossils revealed by melting glaciers, and the radiocarbon dating of the fossils. Emphasis is on the samples found in growth position (in situ) and in good condition. That kind of samples suggest that they have been in the ice for the whole period from the time of their burial by ice to the time of the the ice melting and revealing them once again. Such samples also suggest that at the time they were released from ice it was roughly warmer than at any time after their burial in ice. Note that many of the papers presented below are concentrating in revealing historical glacier fluctuations, so they don’t even discuss their findings in the context of the modern climate change (except the few that do discuss it, Thompson et al., 2006, being the prime example). The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

UPDATE (April 18, 2012): Anderson et al. (2008) added. Thanks to Barry for pointing it out (in another paperlist thread).

Latest Pleistocene and Holocene glacier fluctuations in western Canada – Menounos et al. (2009) “We summarize evidence of the latest Pleistocene and Holocene glacier fluctuations in the Canadian Cordillera. Our review focuses primarily on studies completed after 1988, when the first comprehensive review of such evidence was published. … Radiocarbon ages of wood collected from glacier forefields reveal six major periods of glacier advance: 8.59–8.18, 7.36–6.45, 4.40–3.97, 3.54–2.77, 1.71–1.30 ka, and the past millennium.” [Link to PDF]

A millennial perspective on Arctic warming from 14C in quartz and plants emerging from beneath ice caps – Anderson et al. (2008) “Observational records show that the area of ice caps on northern Baffin Island, Arctic Canada has diminished by more than 50% since 1958. Fifty 14C dates on dead vegetation emerging beneath receding ice margins document the persistence of some of these ice caps since at least 350 AD. In situ cosmogenic 14C in rock surfaces, and 14C in plant macrofossils from lake-sediment cores demonstrate that the plateau remained ice-free through the middle Holocene, but has supported ice caps for more than 2000 of the past 2800 years. The rapid disappearance of these ice caps over the past century, despite decreasing summer insolation, further demonstrates the unusual character of 20th Century warmth. Widespread ice-cap expansion ∼1280 AD early in the Little Ice Age, and intensified expansion ∼1450 AD, coincide with peak stratospheric volcanic aerosol loading and reduced solar luminosity, suggesting that these mechanisms may have initiated ice-cap growth, subsequently maintained by strong positive feedbacks.” Anderson, R. K., G. H. Miller, J. P. Briner, N. A. Lifton, and S. B. DeVogel (2008), A millennial perspective on Arctic warming from 14C in quartz and plants emerging from beneath ice caps, Geophys. Res. Lett., 35, L01502, doi:10.1029/2007GL032057. [Full text]

Recent marginal changes of the Mittivakkat Glacier, Southeast Greenland and the discovery of remains of reindeer (Rangifer tarandus), polar bear (Ursus maritimus) and peaty material – Tvis Knudsen et al. (2008) “During field observations in August 2005 antler remains of a reindeer were found at a recently deglaciated site at about 500 m asl., and bones from a polar bear were found at about 300 m asl. along the margin of Mittivakkat Glacier, Southeast Greenland. Radio carbon dating determined the age of the samples to 720 14C years and 350 14C years, respectively. In August 2006 old surface vegetation covering peaty material became exposed due to ice recession close to the site where the antler was found. The radio carbon age of small roots from the material was determined to 1530 14C years, and is in agreement with dating of woody remains of Salix glauca found close by, at the top of a nearby nunatak in 1999. The antler indicates that reindeer lived in the area when the glacier began to advance from a position where it was close to or smaller than today. The vegetation surface and peaty material indicate that the climate was warmer before the onset of the Little Ice Age in Southeast Greenland than today.” [Link to PDF]

Western Canadian glaciers advance in concert with climate change circa 4.2 ka – Menounos et al. (2008) “Disparate climate proxies from the Northern Hemisphere record a climate event at 4.2–3.8 ka. Here we show that glaciers throughout the mountain ranges of western Canada advanced at about this time. This conclusion is based on (1) new and previously reported radiocarbon ages on in situ stumps, logs, branches, and soils exposed by recent retreat in glacier forefields and…” [Link to PDF]

Ice-borne prehistoric finds in the Swiss Alps reflect Holocene glacier fluctuations – Grosjean et al. (2007) “During the hot summer of 2003, reduction of an ice field in the Swiss Alps (Schnidejoch) uncovered spectacular archaeological hunting gear, fur, leather and woollen clothing and tools from four distinct windows of time: Neolithic Age (4900 to 4450 cal. yr BP), early Bronze Age (4100-3650 cal. yr BP), Roman Age (1st-3rd century AD), and Medieval times (8-9th century AD and 14-15th century AD). … The preservation of Neolithic leather indicates permanent ice cover at that site from ca. 4900 cal. yr BP until AD 2003, implying that the ice cover was smaller in 2003 than at any time during the last 5000 years. Current glacier retreat is unprecedented since at least that time. This is highly significant regarding the interpretation of the recent warming and the rapid loss of ice in the Alps.” [Link to PDF]

Pre-`Little Ice Age’ glacier fluctuations in Garibaldi Provincial Park, Coast Mountains, British Columbia, Canada – Koch et al. (2007) “Holocene glacier fluctuations prior to the `Little Ice Age’ in Garibaldi Provincial Park in the British Columbia Coast Mountains were reconstructed from geomorphic mapping and radiocarbon ages on 37 samples of growth-position and detrital wood from glacier forefields. … The first well-documented advance dates to 7700—7300 14C yr BP. Subsequent advances date to 6400—5100, 4300, 4100—2900 and 1600—1100 14C yr BP. … Periods of advance in Garibaldi Park are broadly synchronous with advances elsewhere in the Canadian Cordillera, suggesting a common climatic cause.” [Link to PDF]

Abrupt tropical climate change: Past and present – Thompson et al. (2006) “Finally, rooted, soft-bodied wetland plants, now exposed along the margins as the Quelccaya ice cap (Peru) retreats, have been radiocarbon dated and, when coupled with other widespread proxy evidence, provide strong evidence for an abrupt mid-Holocene climate event that marked the transition from early Holocene (pre-5,000-yr-B.P.) conditions to cooler, late Holocene (post-5,000-yr-B.P.) conditions. … These three lines of evidence argue that the present warming and associated glacier retreat are unprecedented in some areas for at least 5,200 yr.” [Link to PDF]

Multicentury glacier fluctuations in the Swiss Alps during the Holocene – Joerin et al. (2006) “Subfossil remains of wood and peat from six Swiss glaciers found in proglacial fluvial sediments indicate that glaciers were smaller than the 1985 reference level and climatic conditions allowed vegetation growth in now glaciated basins. An extended data set of Swiss glacier recessions consisting of 143 radiocarbon dates is presented to improve the chronology of glacier fluctuations. A comparison with other archives and dated glacier advances suggests 12 major recession periods occurring at 9850- 9600, 9300-8650, 8550-8050, 7700-7550, 7450-6550, 6150-5950, 5700-5500, 5200-4400, 4300-3400, 2800-2700, 2150-1850, 1400-1200 cal. yr BP.” [Link to PDF]

Dendroglaciological Evidence For A Neoglacial Advance Of the Saskatchewan Glacier, Banff National Park, Canadian Rocky Mountains – Wood & Smith (2004) “Seventeen glacially sheared stumps in growth position and abundant detrital wood fragments were exposed by stream avulsion at the terminus of the Saskatchewan Glacier in 1999. The stumps lay buried beneath the glacier and over 5 m of glacial sediment until historical recession and stream incision exposed the 225- to 262-year-old stand of subalpine fir, Englemann spruce and whitebark pine trees. Crossdating and construction of two radiocarbon-controlled floating tree-ring chronologies showed that all the subfossil stumps and boles exposed at this location were killed during a Neoglacial advance of the Saskatchewan Glacier 2,910 ±60 to 2,730 ±60 14C years B.P.” [Link to PDF]

The Alpine “Iceman” and Holocene Climatic Change – Baroni & Orombelli (1996) “The finding of a prehistoric mummified corpse at the upper edge of the accumulation area of an alpine glacier, together with its unique set of artifacts, provided new information on glacier dimensions during the little-known phases of major glacier shrinkage that characterized the warmest parts of the Holocene. The sudden burial of the corpse in a permanent snow cover occurred 5300–5050 cal yr B.P., indicating a significant climatic change that induced glacier expansion at the beginning of Neoglaciation. New geomorphologic data and two AMS14C ages from buried soils suggest that the present glacier size, following over 100 yr of shrinkage, is comparable to that immediately preceding Neoglaciation. Therefore, we can deduce that the current global climatic warming may have interrupted the environmental conditions prevailing in the Alps during Neoglacial time, restoring characteristics similar to those prevailing during theclimatic optimumthat were never achieved during the second half of the Holocene.” [Link to PDF]

Radiocarbon dates from Nordenskjöld Glacier, South Georgia, and their implications for late Holocene glacier chronology – Gordon (1987) “Recent recession of Nordenskjöld Glacier has exposed in situ a bed of peat formerly covered by the glacier. Radiocarbon dates on the peat allow an estimate of the minimum duration of a period of vegetation development and less extensive ice cover than occurs at present between 2230 ± 70 and 3330 ± 120 years BP (equivalent to calendar age ranges of 2122-2334 and 3395-3689 years BP).” [Link to PDF]

Glacier contraction during the middle Holocene in the western Italian Alps: Evidence and implications – Porter & Orombelli (1985) “Radiocarbon dates of peat from the top and base of a bog exposed by recent retreat of Rutor Glacier show that the glacier front terminated upvalley from the bog from 8400 until at least 6000 B.P.”

Entombed Plant Communities Released by a Retreating Glacier at Central Ellesmere Island, Canada – Bergsma et al. (1984) “The release of a dead but well-preserved high arctic plant community, entombed for about 400 radiocarbon years… under glacial ice at Twin Glacier, central Ellesmere Island… is reported. Remarkably intact plants have been emerging from under the ablating front of this polar glacier which has been retreating for several decades at an average rate of 4.1 m yr-1 over the last 22 years. … The excellent preservation of the plants supports the thesis that polar glaciers are frozen to their bases, and hence their movements are by internal deformation rather than by erosive basal sliding.” [Link to PDF]

Preservation of vegetation and patterned ground under a thin ice body in northern Baffin Island, N.W.T. – Falconer (1966), Geographical Bulletin, 8(2): 194-200. Described in Bergsma et al. (1984): “The most relevant work with respect to this report is that of Falconer (1966), who described the release of undisturbed, vegetated patterned ground features by the rapid recesson of a thin body of Tiger Ice Cap in northern Baffin Island. Exposed moss, Polytrichum juniperinum, was radiocarbon-dated at 330 ± 75 years.”

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Papers on atmospheric carbon dioxide concentration measurements

Posted by Ari Jokimäki on September 14, 2009

This list of papers contains observations of carbon dioxide concentration in Earth’s atmosphere. This is a surprisingly broad subject, and the list below tries to cover some of the different measurement techniques and different aspects of the issue. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

UPDATE (February 18, 2020): Hakkarainen et al. (2019) added.
UPDATE (June 28, 2012): Chédin et al. (2003) and Buchwitz et al. (2007) added.
UPDATE (June 19, 2012): Benedict (1912), Krogh & Brandt (1929), Haldane (1936), Carpenter (1937), Buch (1934), Buch (1939), Buch (1939), Buch (1948), Glueckauf (1951), Effenberger (1951), Stepanova (1952), Slocum (1955), Callendar (1940), Callendar (1958), Bray (1959), Wigley (1983), Fonselius & Koroleff (1955), and Fonselius et al. (1956) added.
UPDATE (December 6, 2010): Bolin & Eriksson (1957) added.
UPDATE (July 11, 2010): Longinelli et al. (2010) added.
UPDATE (July 1, 2010): Jiang et al. (2010) added.
UPDATE (June 25, 2010): Kulawik et al. (2010) added.
UPDATE (January 22, 2010): Armstrong (1879), de Saussure (1828), and de Saussure (1830) added.

Analysis of Four Years of Global XCO2 Anomalies as Seen by Orbiting Carbon Observatory-2 – Hakkarainen et al. (2019)
Abstract: “NASA’s carbon dioxide mission, Orbiting Carbon Observatory-2, began operating in September 2014. In this paper, we analyze four years (2015–2018) of global (60°S–60°N) XCO2 anomalies and their annual variations and seasonal patterns. We show that the anomaly patterns in the column-averaged CO2 dry air mole fraction, XCO2, are robust and consistent from year-to-year. We evaluate the method by comparing the anomalies to fluxes from anthropogenic, biospheric, and biomass burning and to model-simulated local concentration enhancements. We find that, despite the simplicity of the method, the anomalies describe the spatio-temporal variability of XCO2 (including anthropogenic emissions and seasonal variability related to vegetation and biomass burning) consistently with more complex model-based approaches. We see, for example, that positive anomalies correspond to fossil fuel combustion over the major industrial areas (e.g., China, eastern USA, central Europe, India, and the Highveld region in South Africa), shown as large positive XCO2 enhancements in the model simulations. We also find corresponding positive anomalies and fluxes over biomass burning areas during different fire seasons. On the other hand, the largest negative anomalies correspond to the growing season in the northern middle latitudes, characterized by negative XCO2 enhancements from simulations and high solar-induced chlorophyll fluorescence (SIF) values (indicating the occurrence of photosynthesis). The largest discrepancies between the anomaly patterns and the model-based results are observed in the tropical regions, where OCO-2 shows persistent positive anomalies over every season of every year included in this study. Finally, we demonstrate how XCO2 anomalies enable the detection of anthropogenic signatures for several local scale case studies, both in the Northern and Southern Hemisphere. In particular, we analyze the XCO2 anomalies collocated with the recent TROPOspheric Monitoring Instrument NO2 observations (used as indicator of anthropogenic fossil fuel combustion) over the Highveld region in South Africa. The results highlight the capability of satellite-based observations to monitor natural and man-made CO2 signatures on global scale.”
Citation: Janne Hakkarainen, Iolanda Ialongo, Shamil Maksyutov, David Crisp (2019). Remote Sensing 11(7):850.

Decadal changes in atmospheric CO2 concentration and δ13C over two seas and two oceans: Italy to New Zealand – Longinelli et al. (2010) “Continuous measurements of the CO2 concentration were repeatedly carried out from 1996 to 2007 between Italy and New Zealand by means of a Siemens Ultramat 5E analyzer assembled for shipboard use. Along the ship routes discrete air samples were collected from 1998 to 2005 using four-litre Pyrex flasks. The δ13C of the CO2 from the flask air samples was measured according to well-established techniques. … The yearly rate of increase of the CO2 concentration between 1996 and 2007 for the Indian Ocean is of about 1.9 ppmv yr-1, in excellent agreement with the NOAA/CMDL measurements carried out during the same period at Mahé Isld. (Indian Ocean) and Cape Grim (Tasmania). The δ13C results obtained from the CO2 of flask samples collected in the Mediterranean show the effect of anthropogenic emissions, though this is considerably smaller than expected. This inconsistency may be related to the large terrestrial biospheric sink of CO2 in the Northern Hemisphere.”

Interannual variability of mid-tropospheric CO2 from Atmospheric Infrared Sounder – Jiang et al. (2010)
In this paper, we use AIRS data to examine the interannual variability of CO2 and find significant correlations between AIRS mid-tropospheric CO2 and large-scale atmospheric dynamics. During El Niño events, mid-tropospheric CO2 over the central Pacific Ocean is enhanced whereas it is reduced over the western Pacific Ocean as a result of the change in the Walker circulation. The variation of AIRS CO2 in the high latitudes of the northern hemisphere is closely related to the strength of the northern hemispheric annular mode.
Jiang, X., M. T. Chahine, E. T. Olsen, L. L. Chen, and Y. L. Yung (2010), Interannual variability of mid-tropospheric CO2 from Atmospheric Infrared Sounder, Geophys. Res. Lett., 37, L13801, doi:10.1029/2010GL042823.

Characterization of Tropospheric Emission Spectrometer (TES) CO2 for carbon cycle science – Kulawik et al. (2010) “We present carbon dioxide (CO2) estimates from the Tropospheric Emission Spectrometer (TES) on the EOS-Aura satellite launched in 2004. … Comparisons to Mauna Loa data show a correlation of 0.92, a standard deviation of 1.3 ppm, a predicted error of 1.2 ppm, and a ~2% low bias, which is subsequently corrected. Comparisons to SGP aircraft data over land show a correlation of 0.67 and a standard deviation of 2.3 ppm. TES data between 40° S and 45° N for 2006–2007 are compared to surface flask data, GLOBALVIEW, the Atmospheric Infrared Sounder (AIRS), and CarbonTracker. Comparison to GLOBALVIEW-CO2 ocean surface sites shows a correlation of 0.60 which drops when TES is offset in latitude, longitude, or time. At these same locations, TES shows a 0.62 and 0.67 correlation to CarbonTracker at the surface and 5 km, respectively.” [Full text]

First year of upper tropospheric integrated content of CO2 from IASI hyperspectral infrared observations – Crevoisier et al. (2009) “Simultaneous observations from the Infrared Atmospheric Sounding Interferometer (IASI) and from the Advanced Microwave Sounding Unit (AMSU), launched together onboard the European MetOp platform in October 2006, are used to retrieve an upper tropospheric content of carbon dioxide (CO2) covering the range 11–15 km (100–300 hPa), in clear-sky conditions, in the tropics, over sea, for the first year of operation of MetOp (January 2008–December 2008). … Features of the retrieved CO2 space-time distribution include: … (4) signatures of CO2 emissions (such as biomass burning) transported to the troposphere.” [Full text]

A 4-year zonal climatology of lower tropospheric CO2 derived from ocean-only Atmospheric Infrared Sounder observations – Strow & Hannon (2008) “A 4-year zonally averaged climatology of atmospheric CO2, ocean only, between ±60° latitude has been derived from the Atmospheric Infrared Sounder (AIRS) radiances. Using only very clear fields of view, the CO2 profile in the computed radiances is scaled until agreement is found with observations. ECMWF forecast and analysis fields are used for the temperature profile in the computed radiances. The AIRS channels used to derive CO2 amounts are nominally sensitive to CO2 variability in the ∼300–800 mbar region (2–9 km), significantly lower in the atmosphere than that in previous studies using AIRS. Validation using aircraft measurements of CO2 at 650 mbar indicates that the AIRS CO2 results presented here are accurate to the 0.5–1.0 ppm level. The AIRS-derived climatology clearly exhibits the CO2 rectifier effect, with mean CO2 values several parts per million lower than in those in the boundary layer. The AIRS CO2 seasonal cycle has a relatively constant amplitude of ∼3 ppm from +10° to +60° latitude, which matches the boundary layer seasonal cycle amplitude near +10° latitude but is about three times smaller than that in the boundary layer amplitude at +60° latitude. Phase comparisons between the AIRS and boundary layer CO2 seasonal cycles show the boundary layer phase leading AIRS in the Northern Hemisphere until ∼+10° latitude, where the phases cross and the AIRS higher-altitude CO2 begins to lead the boundary layer phase down to ∼−10° latitude. These results may offer new insight into CO2 interhemispherical transport. Growth rates derived from the AIRS CO2 climatology are 2.21 ± 0.24 ppm/year, in good agreement with in situ measurements.” Strow, L. L., and S. E. Hannon (2008), A 4-year zonal climatology of lower tropospheric CO2 derived from ocean-only Atmospheric Infrared Sounder observations, J. Geophys. Res., 113, D18302, doi:10.1029/2007JD009713

Assessing the near surface sensitivity of SCIAMACHY atmospheric CO2 retrieved using (FSI) WFM-DOAS – Barkley et al. (2007) “Satellite observations of atmospheric CO2 offer the potential to identify regional carbon surface sources and sinks and to investigate carbon cycle processes. … Furthermore, comparisons to in-situ CO2 observations demonstrate that SCIAMACHY is capable of observing lower tropospheric variability on (at least) monthly timescales. … The SCIAMACHY/MODIS comparison reveals that at many of the sites, the amount of CO2 variability is coincident with the amount of vegetation activity. It is evident, from this analysis, that SCIAMACHY therefore has the potential to detect CO2 variability within the lowermost troposphere arising from the activity of the terrestrial biosphere.” [Full text]

First direct observation of the atmospheric CO2 year-to-year increase from space – Buchwitz et al. (2007) “The reliable prediction of future atmospheric CO2 concentrations and associated global climate change requires an adequate understanding of the CO2 sources and sinks. The sparseness of the existing surface measurement network limits current knowledge about the global distribution of CO2 surface fluxes. The retrieval of CO2 total vertical columns from satellite observations is predicted to improve this situation. Such an application however requires very high accuracy and precision. We report on retrievals of the column-averaged CO2 dry air mole fraction, denoted XCO2, from the near-infrared nadir spectral radiance and solar irradiance measurements of the SCIAMACHY satellite instrument between 2003 and 2005. We focus on northern hemispheric large scale CO2 features such as the CO2 seasonal cycle and show – for the first time – that the atmospheric annual increase of CO2 can be directly observed using satellite measurements of the CO2 total column. The satellite retrievals are compared with global XCO2 obtained from NOAA’s CO2 assimilation system CarbonTracker taking into account the spatio-temporal sampling and altitude sensitivity of the satellite data. We show that the measured CO2 year-to-year increase agrees within about 1 ppm/year with CarbonTracker. We also show that the latitude dependent amplitude of the northern hemispheric CO2 seasonal cycle agrees with CarbonTracker within about 2 ppm with the retrieved amplitude being systematically larger. The analysis demonstrates that it is possible using satellite measurements of the CO2 total column to retrieve information on the atmospheric CO2 on the level of a few parts per million.” Buchwitz, M., Schneising, O., Burrows, J. P., Bovensmann, H., Reuter, M., and Notholt, J.: First direct observation of the atmospheric CO2 year-to-year increase from space, Atmos. Chem. Phys., 7, 4249-4256, doi:10.5194/acp-7-4249-2007, 2007. [Full text, correction]

The role of carbon dioxide in climate forcing from 1979 to 2004: introduction of the Annual Greenhouse Gas Index – Hofmann et al. (2006) “High-precision measurements of CO2, CH4, N2O, CFC-12, CFC-11 (major greenhouse gases) and 10 minor halogenated gases from a globally distributed network of air sampling sites are used to calculate changes in radiative climate forcing since the pre-industrial era (1750) for the period of measurement, 1979–2004. … Of the five major long-lived gases that contribute to radiative climate forcing, CO2 and N2O are the only gases for which the atmospheric concentrations continue to rise. … Most of the increase in the [Annual Greenhouse Gas Index] is related to CO2.” [Full text]

Comparison of SCIAMACHY and AIRS CO2 measurements over North America during the summer and autumn of 2003 – Barkley et al. (2006) “This comparison demonstrates that there is a general consistency between the CO2 distributions retrieved by AIRS and SCIAMACHY, when the different vertical sensitivities of the instruments are taken into account.” [Full text]

First global measurement of midtropospheric CO2 from NOAA polar satellites: Tropical zone – Chédin et al. (2003) “Midtropospheric mean atmospheric CO2 concentration is retrieved from the observations of the NOAA series of polar meteorological satellites, using a nonlinear regression inference scheme. For the 4 years of the present analysis (July 1987 to June 1991), monthly means of the CO2 concentration retrieved over the tropics (20°N to 20°S) from NOAA 10 show very good agreement with what is presently known. Not only the phase of the seasonal variations (location of the peaks) but also their amplitude and their latitudinal evolution match quite well recent in situ observations made by properly equipped commercial airliners measuring in an altitude range similar to the one favored by the satellite observations. Moreover, the annual trend inferred corresponds to the known increase in the concentration of CO2 as a result of human activities. Also, the impact of El Niño-Southern Oscillation events is clearly seen and confirms analyses of in situ or aircraft observations and of model simulations. Forty-eight maps of monthly mean midtropospheric CO2 concentration have been produced at a resolution of 15° × 15°. A rough estimate of the method-induced standard deviation of these retrievals is of the order of 3.6 ppmv (around 1%). The coming analysis of the almost 25 years of archive already accumulated by the NOAA platforms should contribute to a better understanding of the carbon cycle. A simulation of the extension of the method to the next generation high-spectral-resolution instruments, with very encouraging results, is presented.” Chédin, A., S. Serrar, N. A. Scott, C. Crevoisier, and R. Armante (2003), First global measurement of midtropospheric CO2 from NOAA polar satellites: Tropical zone, J. Geophys. Res., 108, 4581, doi:10.1029/2003JD003439. [Conference paper]

A High-Precision Fast-Response Airborne CO2 Analyzer for In Situ Sampling from the Surface to the Middle Stratosphere – Daube et al. (2002) “Two in situ CO2 analyzers have been developed for deployment on the NASA ER-2 aircraft and on stratospheric balloons. … In this paper, the instrumentation and calibration procedures for both instruments are described in detail. An intercomparison of the two instruments during the Photochemistry of Ozone Loss in the Arctic Region In Summer (POLARIS) project showed that, on average, the instruments agreed to within 0.05 ppmv.”

Atmospheric carbon dioxide and its stable isotope ratios, methane, carbon monoxide, nitrous oxide and hydrogen from Shetland Isles – Francey et al. (1998) “Since November 1992, 0.5 glass flasks have been filled approximately monthly with dry marine air from Shetland Isles, Scotland (60.2°N, 1.2°W) and transported to CSIRO, Australia for analyses. The Shetland site is part of a CSIRO global flask network with 10-12 sites, anchored to continuous high precision in situ measurements made at the Australian Cape Grim Baseline Station (40.7°S, 144.7°E), a primary station in the Global Atmosphere Watch programme (GAW) coordinated by the World Meteorological Organisation. The methodology is summarised, and Shetland results for CO2, CH4, N2O, CO, H2 and δ13C, δ18O of CO2 presented for the period 1992-1996.”

Increased activity of northern vegetation inferred from atmospheric CO2 measurements – Keeling et al. (1996) “Here we report that the annual amplitude of the seasonal CO2 cycle has increased by 20%, as measured in Hawaii, and by 40% in the Arctic, since the early 1960s. These increases are accompanied by phase advances of about 7 days during the declining phase of the cycle, suggesting a lengthening of the growing season. In addition, the annual amplitudes show maxima which appear to reflect a sensitivity to global warming episodes that peaked in 1981 and 1990. We propose that the amplitude increases reflect increasing assimilation of CO2 by land plants in response to climate changes accompanying recent rapid increases in temperature.”

Evidence from polar ice cores for the increase in atmospheric CO2 in the past two centuries – Neftel et al. (1985) “The most reliable assessment of the ancient atmospheric CO2 concentration is derived from measurements of air occluded in ice cores. An ice core from Siple Station (West Antartica) that allows determination of the enclosed gas concentration with very good time resolution has recently become available. We report here measurements of this core which now allow us to trace the development of the atmospheric CO2 from a period overlapping the Mauna Loa record back over the past two centuries.”

The pre-industrial carbon dioxide level – Wigley (1983) “Recent indirect data and direct measurements from ice cores point towards a ‘pre-industrial’ CO2 level of around 260–270 ppmv, considerably below the commonly assumed value of 290 ppmv. Early measurements from the southern hemisphere tend to favour the lower value.” T. M. L. Wigley, Climatic Change, Volume 5, Number 4 (1983), 315-320, DOI: 10.1007/BF02423528.

The concentration and isotopic abundances of carbon dioxide in the atmosphere – Keeling (1960) “A systematic variation with season and latitude in the concentration and isotopic abundance of atmospheric carbon dioxide has been found in the northern hemisphere. In Antarctica, however, a small but persistent increase in concentration has been found.” [Full text]

An Analysis of the Possible Recent Change in Atmospheric Carbon Dioxide Concentration – Bray (1959) “Criteria minimizing differences in operators, location, and time of observation are established for selecting comparative data on atmospheric CO2 concentration during the past 100 years. The resulting selection showed in all cases the period 1907–1956 to have a higher mean than 1857–1906. The difference between means was not statistically significant for 5 unweighted comparisons. Weighting by estimates of reliability resulted in a significant difference for yearly and summer non-urban values, but not for the other 3 comparisons. Additional comparisons of all values in the study, of six entire distributions, and of five paired studies with closely comparable data showed increases in a more recent period, with one exception. The magnitude of the increase for weighted yearly non-urban data was 25 ppm (from 294 to 319) for the quarters 1857–1881 to 1932–1956. Several possible explanations for the increase include: 1) an actual atmospheric increase, 2) a coincidence of the influence of micro-atmospheres, 3) improvement (or change) in chemical technique.” J. R. Bray, Tellus, Volume 11, Issue 2, pages 220–230, May 1959, DOI: 10.1111/j.2153-3490.1959.tb00023.x. [Full text]

On the Amount of Carbon Dioxide in the Atmosphere – Callendar (1958) “Of late years there has been much interest in the effect of human activities on the natural circulation of carbon. This demands a knowledge of the amount of CO2 in atmosphere both now and in the immediate past. Here the average amount obtained by 30 of the most extensive series of observations between 1866 and 1956 is presented, and the reliability of the 19th century measurements discussed. A base value of 290 p.p.m. is proposed for the year 1900. Since then the observations show a rising trend which is similar in amount to the addition from fuel combustion. This result is not in accordance with recent radio carbon data, but the reasons for the discrepancy are obscure, and it is concluded that much further observational data is required to clarify this problem. Some old values, showing a remarkable fall of CO2 in high southern latitudes, are assembled for comparison with the anticipated new measurements, to be taken in this zone during the Geophysical Year.” G. S. Callendar, Tellus, Volume 10, Issue 2, pages 243–248, May 1958, DOI: 10.1111/j.2153-3490.1958.tb02009.x. [Full text]

Changes in the Carbon Dioxide Content of the Atmosphere and Sea due to Fossil Fuel Combustion – Bolin & Eriksson (1957) “This problem warrants further investigation, but already the present treatment indicates that an appreaciable increase of the amount of CO2 in the atmosphere may have occurred since last century. This increase will continue and should be detectable with present techniques for measuring CO2 in the atmosphere within a few years in areas with little or no local pollution due to fossil fuel combustion as in the Antarctica or on Hawaii.” [Full text]

Variations in concentration and isotopic abundances of atmospheric carbon dioxide – Keeling (1957) “In the study now to be described, attention was directed to a study of air in virgin forests and in grassland where the air was likely to be affected by biological processes, and at desert and high mountain stations where local sources or acceptors of carbon dioxide being absent, the composition of the air should be essentially that of free atmosphere.” [Full text]

Carbon Dioxide Variations in the Atmosphere – Fonselius et al. (1956) “The Scandinavian CO2-sampling in 1955 is described. The mean results for the calendar year are given. Earlier CO2-measurements are discussed and a figure showing most of these values is given. The theory of Callendar is discussed and the Scandinavian values are compared with Callendar’s. The seasonal variations at the Scandinavian stations are compared and the results discussed. The possibility of drawing synoptic maps is discussed and one example is shown. The desirability of systematic CO2-measurements on a global scale is emphasized.” Stig Fonselius, Folke Koroleff, Karl-Erik Wärme, Tellus, Volume 8, Issue 2, pages 176–183, May 1956, DOI: 10.1111/j.2153-3490.1956.tb01208.x. [Full text]

Microdetermination of CO2 in the Air, with Current Data for Scandinavia – Fonselius & Koroleff (1955) “Krogh and Brandt Rehbergs method for estimation of CO2 in atmospheric air has been investigated and modified. The method is used for continous investigation of the CO2 content of the air in Scandinavia. A permanent net of sampling stations has been established, 6 in Sweden, 4 in Finland, 3 in Norway and 2 in Denmark. The samples are taken three times each month. A simple method of taking air samples is described. Current data for November, December 1954 and January 1955 are published.” Stig Fonselius, Folke Koroleff, Tellus, Volume 7, Issue 2, pages 258–265, May 1955, DOI: 10.1111/j.2153-3490.1955.tb01160.x. [Full text]

Has the amount of carbon dioxide in the atmosphere changed significantly since the beginning of the twentieth century? – Slocum (1955) “The search for causes of the rising temperatures in some geographic areas during the twentieth century has directed interest toward the amount of atmospheric carbon dioxide (CO2). If the carbon dioxide added by the combustion of fossil fuels remains as a net increase, any temperature-changing effects of its presence as a minor constituent of the atmosphere should be cumulatively operative as the amount increases. In this paper, the physical knowledge of atmospheric CO2 is examined and the available nineteenth and twentieth century observations of the atmospheric CO2 concentration are summarized to ascertain the extent to which they corroborate claims that the amount of atmospheric CO2 has increased since the nineteenth century. In the light of the uncertainty of both physical knowledge and of statistical analysis, it is concluded that the question of a trend in atmospheric CO2 concentration remains an open subject.” Giles Slocum, Mon. Wea. Rev., 83, 225–231. doi:;2. [Full text]

A selective annotated bibliography of carbon dioxide in the atmosphere – Stepanova (1952) Stepanova, N. A., 1952, Meteor. Abs. Bibl. 3, pp. 137-170.

The composition of atmospheric air – Glueckauf (1951) No abstract. Glueckauf, E., 1951, The composition of atmospheric air. Compendium of Meteorology, Amer. Meteorol. Soc., Boston, pp. 3-10. [Full text available in abstract page]

Messmethoden zur Bestimmung des CO2-Gehaltes der Atmosphare und die Bedeutung derartiger Messungen fur die Bioklimatologie und Meteorologie (2. Teil) – Effenberger (1951) No abstract available online. Effenberger, E., Ann. der Meteorologie 4. 1o/12, p. 417.

Der Kohlendioxydgehalt der Luft als Indikator der meteorologischen Luftqualität – Buch (1948) No abstract available online. Kurt Buch, Geophysica, vol. 3, 1948, pp. 63-79.

Variations of the amount of carbon dioxide in different air currents – Callendar (1940) “The first measurements to determine the composition of the atmosphere were made at least 180 years ago, but chemists worked more than a century before they obtained really accurate values for the amount of carbon dioxide in the air. In the following: a brief review is given of the present state of knowledge concerning the variations of atmospheric carbon dioxide, together with some observations which appear to show that the amount of this gas in the air has increased of late years.” G. S. Callendar, Quarterly Journal of the Royal Meteorological Society, Volume 66, Issue 287, pages 395–400, October 1940, DOI: 10.1002/qj.49706628705.

Kohlensaure in Atmosphare und Meer an der Grenze zum Arktikum – Buch (1939) No abstract available online. Buch, K., 1939, Acta Acad. Aboensis, Mat. et Phys. XI, 12.

Beobachtungen uber das Kohlensauregleichgewicht und uber den Kohlensaureaustausch zwischen Atmosphare und Meer im Nordatlantischen Ozean – Buch (1939) No abstract available online. Buch, K., 1939, Ibid., XI, 9.

The Constancy of the Atmosphere with Respect to Carbon Dioxide and Oxygen Content – Carpenter (1937) No abstract. Thorne M. Carpenter, J. Am. Chem. Soc., 1937, 59 (2), pp 358–360, DOI: 10.1021/ja01281a040.

Carbon Dioxide Content of Atmospheric Air – Haldane (1936) “DURING the last nine months of his life my father, Prof. J. S. Haldane, was engaged, in collaboration with Dr. R. H. Makgill, in the systematic analysis of atmospheric air. Owing to his death and the absence of Dr. Makgill in New Zealand, some time may elapse before the full results of their work are published. But certain of them are of enough general interest to warrant a preliminary note.” J. B. S. Haldane, Nature 137, 575 (4 April 1936) | doi:10.1038/137575a0.

Beobachtungen über chemische Faktoren in der Nordsee, zwischen Nordsee und Island, sowie auf dem Schelfgebiete nordlich von Island – Buch (1934) No abstract available online. Buch, K., Conseil perm. intern. p. l’exploration de la mer. Rapp. et proc. verb., 89, 13.

CO2-Bestimmungen in der Atmospharischen Luft durch Mikrotitration – Krogh & Brandt (1929) No abstract available online. Krogh, A., und Brandt, Rehberg, P., 1929, Biochemische Zeifschr. 205, 265.

The composition of the atmosphere with special reference to its oxygen content – Benedict (1912) No abstract. Benedict, F. G., 1929, Washington D.C. Carnegie Inst. [Full text available in abstract page]

On the Variations in the Amount of Carbon Dioxide in the Air of Kew during the Years 1898-1901 – Brown & Escombe (1905) “As part of the routine work connected with our investigation of the processes of photosynthesis in plants, an account of which has been given in a previous series of papers, it became necessary from time to time to make a large number of determinations of the amount of carbon dioxide present in the air. … The average value for the 91 experiments recorded is 294 volumes of carbon dioxide per 10,000 of air.”

On the Diurnal Variation in the Amount of Carbon Dioxide in the Air – Armstrong (1879) “Although a large share of attention has been given to the elucidation of the causes which influence the amount of carbonic acid present in the atmosphere during the day, no systematic observations with reference to the relative quantities present in the air of the land during the day and the night appear to have been undertaken since the well-known experiments of the younger De Saussure at Chambeisy, upwards of 50 years ago (1826-30), and a similar set by Boussingault at Paris, a few years later, until M. Truchot took up the question in 1873. But the results thus obtained cannot be said to be altogether satisfactory.” Apparently, in this paper Armstrong was able to show that there was a daily variation in carbon dioxide concentration.

Ueber die Schwankungen des Kohlensäure-Gehalts der Atmosphäre – de Saussure (1830) The title translates to “On the fluctuations of the carbon dioxide content of the atmosphere”.

Ueber das Kohlensäure- Gas in der Atmosphäre – de Saussure (1828) The title translates to “About the carbonic acid gas in the atmosphere”.

Closely related

Some of the papers in the list Papers on changes in OLR due to GHG’s are also relevant here.

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Papers on climate predictions of 1970’s

Posted by Ari Jokimäki on September 11, 2009

This list contains papers on climate predictions made in 1970’s so that everyone can see themselves if scientists thought that there is going to be an ice age. So far I haven’t found any papers predicting an ice age during the seventies, but one below at least mentions it as an option. However, I do think that there probably are some papers suggesting an ice age, so I’ll add them if I find any. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

UPDATE (September 12, 2009): The “modern papers on the subject” section added. Peterson et al. (2008), Rasool & Schneider (1971), Bryson & Dittberner (1976) added. Thanks to Paul Middents for pointing out the relevant information for these (see the comments section below).

1970’s papers

Influences of mankind on climate – Kellogg (1979) Review article. “The best estimate of the “greenhouse effect” due to a doubling of carbon dioxide lies between 2 and 3.5°C increase in average surface temperature (Schneider 1975, Augustsson & Ramanathan 1977, Wang et al 1976), and both the models and the record of the behavior of the real climate show that the change in the polar regions will be greater than this by a factor of from 3 to 5, especially in winter (van Loon & Williams 1976, 1977, Borzenkova et al 1976, Manabe & Wetherald 1975, SMIC 1971). When the level of carbon dioxide has risen to 400 ppmv from its present 330 ppmv, the rise in average surface temperature is estimated to be about 1°C.” [Link to PDF (follow the PDF-link given there)]

West Antarctic ice sheet and CO2 greenhouse effect: a threat of disaster – Mercer (1978) “If the global consumption of fossil fuels continues to grow at its present rate, atmospheric CO2 content will double in about 50 years. Climatic models suggest that the resultant greenhouse-warming effect will be greatly magnified in high latitudes. The computed temperature rise at lat 80° S could start rapid deglaciation of West Antarctica, leading to a 5 m rise in sea level.”

The climatic future – Lockwood (1978) “Flohn (1977) has suggested that essentially three alternatives seem to exist for the probable climatic development during the next century: 1 preservations of the present state with variations similar to those observed during the last 200 years; 2 transition to another balance state: that of an ice-age; 3 overwhelming growth of man-made effects: rapid transition to a warm age.” However, see below what Flohn actually thought of the matter in 1977.

Global Air Pollution and Climate Change – Kellogg & Schneider (1978) “Carbon dioxide increase from the burning of fossil fuels at a continuingly increasing rate can cause a 1°C rise in mean surface temperatures by 2000 A.D., and 2-3°C rise by the middle of the next century. There are uncertainties in this projection of mean temperature rise of perhaps a factor of two; and the polar regions are expected to experience an increase several times larger. Other anthropogenic influences, such as the addition to the atmosphere of chlorofluoromethanes, nitrous oxide, and possibly aerosols, may contribute still further to this global warming. The mean surface temperature of the earth by 2000 A. D., if our projection is correct, will be warmer than at any time in the past 1000 years or more.”

Climate and energy: A scenario to a 21st century problem – Flohn (1977) “A dominant role of an increase of CO2 by a factor 2–5 in the next century, accompanied by side effects acting in the same direction, seems to be most likely.”

Global Cooling? – Damon & Kunen (1976) “Because of the rapid diffusion of CO2 molecules within the atmosphere, both hemispheres will be subject to warming due to the atmospheric (greenhouse) effect as the CO2 content of the atmosphere builds up from the combustion of fossil fuels.”

A Non-Equilibrium Model of Hemispheric Mean Surface Temperature – Bryson & Dittberner (1976) “By more completely accounting for those anthropogenic processes which produce both lower tropospheric aerosols and carbon dioxide, such as fossil fuel burning and agricultural burning, we calculate an expected slight decrease in surface temperature with an increase in CO2 content.”

Climate and energy: A scenario to a 21st century problem – Flohn (1976) “Under the assumption of constant natural factors anthropogenic warming and its effects on the Arctic sea-ice may successively lead to climatic states as in 1931–60, in the early Middle Age (900–1200) and in the climatic optimum period ca. 5000 BP. Finally it may result in a complete destruction of the Arctic sea-ice with a drastic shift of all climatic belts towards north, extending even to the interior Tropics.”

The Global Carbon Dioxide Problem – Baes et al. (1976) “Estimates of the consequent warming (“greenhouse”) effect indicate increases in the average surface temperature of the earth that range from possibly acceptable to catastrophic.” [Link to PDF]

Climatic Change: Are We on the Brink of a Pronounced Global Warming? – Broecker (1975) “If man-made dust is unimportant as a major cause of climatic change, then a strong case can be made that the present cooling trend will, within a decade or so, give way to a pronounced warming induced by carbon dioxide. By analogy with similar events in the past, the natural climatic cooling which, since 1940, has more than compensated for the carbon dioxide effect, will soon bottom out. Once this happens, the exponential rise in the atmospheric carbon dioxide content will tend to become a significant factor and by early in the next century will have driven the mean planetary temperature beyond the limits experienced during the last 1000 years.”

Atmospheric Carbon Dioxide and Aerosols: Effects of Large Increases on Global Climate – Rasool & Schneider (1971) “It is found that, although the addition of carbon dioxide in the atmosphere does increase the surface temperature, the rate of temperature increase diminishes with increasing carbon dioxide in the atmosphere. For aerosols, however, the net effect of increase in density is to reduce the surface temperature of Earth. Because of the exponential dependence of the backscattering, the rate of temperature decrease is augmented with increasing aerosol content. An increase by only a factor of 4 in global aerosol background concentration may be sufficient to reduce the surface temperature by as much as 3.5 ° K. If sustained over a period of several years, such a temperature decrease over the whole globe is believed to be sufficient to trigger an ice age.”

Modern papers on the subject

The Myth of the 1970s Global Cooling Scientific Consensus – Peterson et al. (2008) Review article. “An enduring popular myth suggests that in the 1970s the climate science community was predicting “global cooling” and an “imminent” ice age, an observation frequently used by those who would undermine what climate scientists say today about the prospect of global warming. A review of the literature suggests that, on the contrary, greenhouse warming even then dominated scientists’ thinking as being one of the most important forces shaping Earth’s climate on human time scales. More importantly than showing the falsehood of the myth, this review describes how scientists of the time built the foundation on which the cohesive enterprise of modern climate science now rests.” [Link to PDF]

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Papers on global cloud cover trends

Posted by Ari Jokimäki on September 10, 2009

This list of papers contains observations of trends in global cloud cover. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

UPDATE (April 15, 2012): Stowe et al. (1988), Stowe et al. (1989), Stowe et al. (1991), and Eastman et al. (2011) added.
UPDATE (January 27, 2011): Clapp (1964) added.

Variations in Cloud Cover and Cloud Types over the Ocean from Surface Observations, 1954–2008 – Eastman et al. (2011) “Synoptic weather observations from ships throughout the World Ocean have been analyzed to produce a climatology of total cloud cover and the amounts of nine cloud types. About 54 million observations contributed to the climatology, which now covers 55 years from 1954 to 2008. In this work, interannual variations of seasonal cloud amounts are analyzed in 10° grid boxes. Long-term variations O(5–10 yr), coherent across multiple latitude bands, remain present in the updated cloud data. A comparison to coincident data on islands indicates that the coherent variations are probably spurious. An exact cause for this behavior remains elusive. The globally coherent variations are removed from the gridbox time series using a Butterworth filter before further analysis. Before removing the spurious variation, the global average time series of total cloud cover over the ocean shows low-amplitude, long-term variations O(2%) over the 55-yr span. High-frequency, year-to-year variation is seen O(1%–2%). Among the cloud types, the most widespread and consistent relationship is found for the extensive marine stratus and stratocumulus clouds (MSC) over the eastern parts of the subtropical oceans. Substantiating and expanding upon previous work, strong negative correlation is found between MSC and sea surface temperature (SST) in the eastern North Pacific, eastern South Pacific, eastern South Atlantic, eastern North Atlantic, and the Indian Ocean west of Australia. By contrast, a positive correlation between cloud cover and SST is seen in the central Pacific. High clouds show a consistent low-magnitude positive correlation with SST over the equatorial ocean. In regions of persistent MSC, time series show decreasing MSC amount. This decrease could be due to further spurious variation within the data. However, the decrease combined with observed increases in SST and the negative correlation between marine stratus and sea surface temperature suggests a positive cloud feedback to the warming sea surface. The observed decrease of MSC has been partly but not completely offset by increasing cumuliform clouds in these regions; a similar decrease in stratiform and increase in cumuliform clouds had previously been seen over land. Interannual variations of cloud cover in the tropics show strong correlation with an ENSO index.” Stowe, Larry L., H. Y. Michael Yeh, Thomas F. Eck, Charlie G. Wellemeyer, H. Lee Kyle, The Nimbus-7 Cloud Data Processing Team, 1989: Nimbus-7 Global Cloud Climatology. Part II: First Year Results. J. Climate, 2, 671–709. [Full text]

Trends in Observed Cloudiness and Earth’s Radiation Budget What Do We Not Know and What Do We Need to Know? – Norris & Slingo (2009) “Previous investigators have documented multidecadal variations in various cloud and radiation parameters, but no conclusive results are yet available. Problems include the lack of global and quantitative surface measurements, the shortness of the available satellite record, the inability to determine correctly cloud and aerosol properties from satellite data, many different kinds of inhomogeneities in the data, and insuffi cient precision to measure the small changes in cloudiness and radiation that nevertheless can have large impacts on the Earth’s climate.” [Full text]

A Survey of Changes in Cloud Cover and Cloud Types over Land from Surface Observations, 1971–96 – Warren et al. (2007) “The global average trend of total cloud cover over land is small, -0.7% decade-1, offsetting the small positive trend that had been found for the ocean, and resulting in no significant trend for the land–ocean average.” [Full text]

Observed Interdecadal Changes in Cloudiness: Real or Spurious? – Norris (2007) “Substantial agreement exists between global mean time series of surface- and satellite-observed upper-level cloud cover, indicating that the reported variations in this cloud type are likely to be real. … Global mean time series of surface- and satellite-observed low-level and total cloud cover exhibit very large discrepancies, however, implying that artifacts exist in one or both data sets. The global mean satellite total cloud cover time series appears spurious because the spatial pattern of correlations between grid box time series and the global mean time series closely resembles the fields of view of geostationary satellites rather than geophysical phenomena. The surface-observed low-level cloud cover time series averaged over the global ocean appears suspicious because it reports a very large 5%-sky-cover increase between 1952 and 1997. Unless low-level cloud albedo substantially decreased during this time period, the reduced solar absorption caused by the reported enhancement of cloud cover would have resulted in cooling of the climate system that is inconsistent with the observed temperature record.” [Full text]

Arguments against a physical long-term trend in global ISCCP cloud amounts – Evan et al. (2007) “Here we show that trends observed in the ISCCP data are satellite viewing geometry artifacts and are not related to physical changes in the atmosphere. Our results suggest that in its current form, the ISCCP data may not be appropriate for certain long-term global studies, especially those focused on trends.” [Full text]

Diurnal and angular variability of cloud detection: consistency between polar and geosynchronous ISCCP products – Campbell (2006) “There is a view angular dependence for cloud detection from the ISCCP cloud analysis algorithm. Consistency can be demonstrated between polar and geosynchronous satellite observations for this effect. This leads to an angular correction model which can be applied to the either the geosynchronous or polar satellite data time series to correct for systematic angular sampling biases. Similarly there are diurnal sampling biases in the polar ISCCP observations, especially evident over the land areas. Using the ISCCP geosynchronous diurnal sampling, adjustments consistent with the polar ISCCP analysis are derived. Both these corrections lead to a more time consistent regional cloud time series from 1983 to 2001. It is important to correct both time series so that they can be used to corroborate each other in measuring regional cloud changes over the last 20 decades.” [Full text]

Trends in Global Cloud Cover in Two Decades of HIRS Observations – Wylie et al. (2005) “The frequency of cloud detection and the frequency with which these clouds are found in the upper troposphere have been extracted from NOAA High Resolution Infrared Radiometer Sounder (HIRS) polar-orbiting satellite data from 1979 to 2001. The HIRS/2 sensor was flown on nine satellites from the Television Infrared Observation Satellite-Next Generation (TIROS-N) through NOAA-14, forming a 22-yr record. Carbon dioxide slicing was used to infer cloud amount and height. Trends in cloud cover and high-cloud frequency were found to be small in these data. High clouds show a small but statistically significant increase in the Tropics and the Northern Hemisphere. The HIRS analysis contrasts with the International Satellite Cloud Climatology Project (ISCCP), which shows a decrease in both total cloud cover and high clouds during most of this period.” [Full text]

Multidecadal changes in near-global cloud cover and estimated cloud cover radiative forcing – Norris (2005) “This study examines variability in zonal mean surface-observed upper-level (combined midlevel and high-level) and low-level cloud cover over land during 1971–1996 and over ocean during 1952–1997. These data were averaged from individual synoptic reports in the Extended Edited Cloud Report Archive (EECRA). … Zonal mean estimated longwave CCRF [= cloud cover radiative forcing] has decreased over most of the globe. Estimated shortwave CCRF has become slightly stronger over northern midlatitude oceans and slightly weaker over northern midlatitude land areas.” [Full text]

View angle dependence of cloudiness and the trend in ISCCP cloudiness – Campbell (2004) “Over the twenty year ISCCP record, more geosynchronous satellites have been added to the analysis and the mean view angle over the globe has become more vertical. This systematic change in view point convolved with the view angle dependence in cloudiness produces much of the decreasing trend in ISCCP cloud amount, both regionally and globally.” [Full text]

On Trends and Possible Artifacts in Global Ocean Cloud Cover between 1952 and 1995 – Norris (1999) “Synoptic surface cloud observations are used to examine interdecadal variability in global ocean cloud cover between 1952 and 1995. Global mean total cloud cover over the ocean is observed to increase by 1.9% (sky cover) between 1952 and 1995. Global mean low cloud cover over the ocean is observed to increase by 3.6% between 1952 and 1995. … On the other hand, the fact that ships with a common observing practice travel over most of the global ocean suggests a possible observational artifact may be largely responsible for the upward trends observed at all latitudes. Potential causes of artifacts are examined but do not provide likely explanations for the observed interdecadal variability.”

Seasonal Variation of Surface and Atmospheric Cloud Radiative Forcing Over the Globe Derived From Satellite Data – Gupta et al. (1993) “Global distributions of surface and atmospheric cloud radiative forcing parameters have been derived using parameterized radiation models with satellite meteorological data from the International Satellite Cloud Climatology Project, and directly measured top-of-atmosphere radiative fluxes from the Earth Radiation Budget Experiment. … The globally averaged total cloud forcing amounts to a cooling throughout the year…”

Global distribution of cloudcover derived from NOAA/AVHRR operational satellite data – Stowe et al. (1991) “NOAA/NESDIS is developing an algorithm for the remote sensing of globalcloudcover using multi-spectral radiance measurements from the Advanced Very High Resolution Radiometer (AVHRR) on-board NOAA polar orbiting satellites. The current (Phase 1) algorithm uses a sequence of “universal” threshold tests to classify all 2×2 pixel arrays of GAC (4 km) observations into clear, mixed and cloudy categories. A subsequent version of the algorithm (Phase II) will analyze the previous 9-day series of mapped (1/2 degree) “clear” array data to replace the “universal” thresholds with space and time specific values. This will provide more accurate estimates of cloud amount for each pixel. The current algorithm is being implemented into the operational data processing stream for testing and evaluation of experimental products. Eventually, it is intended for use operationally to support weather and climate diagnosis and forecasting programs, as well as to provide clear sky radiance data sets for other remote sensing parameters, e.g., vegetation index, aerosol optical thickness, and sea surface temperature.” L.L. Stowe, E.P. McClain, R. Carey, P. Pellegrino, G.G. Gutman, P. Davis, C. Long, S. Hart,
Advances in Space Research, Volume 11, Issue 3, 1991, Pages 51–54,

Cloud-Radiative Forcing and Climate: Results from the Earth Radiation Budget Experiment – Ramanathan et al. (1989) “Quantitative estimates of the global distributions of cloud-radiative forcing have been obtained from the spaceborne Earth Radiation Budget Experiment (ERBE) launched in 1984. For the April 1985 period, the global shortwave cloud forcing [-44.5 watts per square meter (W/m2)] due to the enhancement of planetary albedo, exceeded in magnitude the longwave cloud forcing (31.3 W/m2) resulting from the greenhouse effect of clouds. Thus, clouds had a net cooling effect on the earth.” [Full text]

Nimbus-7 Global Cloud Climatology. Part II: First Year Results – Stowe et al. (1989) “Regional and seasonal variations in global cloud cover observed by the Nimbus-7 satellite over 1 year are analyzed by examining the 4 midseason months—April, July and October 1979 and January 1980. The Nimbus-7 data set is generated from the Temperature Humidity Infrared Radiometer (THIR) 11.5 micron radiances together with Total Ozone Mapping Spectometer (TOMS)-derived UV reflectivities, climatological atmospheric temperature lapse rates, and concurrent surface temperature and snow/ice information from the Air Force three-dimensional-nephanalysis (3DN) archive. The analysis presented here includes total cloud amount, cloud amounts at high, middle and low altitudes, cirrus and deep convective clouds and cloud and cloud-sky 11.5 micron-derived radiances. Also, noon versus midnight cloud amounts are examined and the Nimbus-7 data are compared to three previously published cloud climatologies. The Nimbus-7 bispectral algorithm gives a monthly mean global noontime cloud cover of 51%, averaged over the 4 months. When only the IR is used, this cloud cover is 49% at noontime and 56% at midnight, indicating that the Earth’s cloud cover has a substantial diurnal cycle. Each hemisphere shows a cloud cover maximum in its summer and a minimum in its winter. The Southern Hemisphere shows more clouds than the Northern Hemisphere except for the month of July. The difference between the cloud-top and clear-scene radiance has maxima in the equatorial cloud belt and minima in the polar regions. Because of thew polar minima and the frequent presence of snow, Nimbus-7 cloud traction estimates are less reliable in the polar regions. In the tropics the data show more clouds at midnight than at noon. Over the tropical ocean, overcast regions show lower cloud top radiation temperatures at noon than at midnight, but over land the reverse occurs. In July, cloud amounts in the intertropical convergence zone (ITCZ) peak at about 10°N latitude with local maxima greater than 70% around the west coasts of Africa and Central America, and from India east to the dateline. Cloud-top radiances indicate that mid- and high-level clouds predominate in the ITCZ, with 5% to 15% each of cirrus and deep convective clouds, respectively. In January, the peak of the ITCZ shifts to 10°S with local cloud maxima greater than 90% over Brazil and to the north and northwest of Australia. Comparison is made with several other cloud data sets, including a look at the new preliminary International Satellite Cloud Climatology Project (ISCCP) results. There are considerable differences among the several data sets examined.” Stowe, Larry L., H. Y. Michael Yeh, Thomas F. Eck, Charlie G. Wellemeyer, H. Lee Kyle, The Nimbus-7 Cloud Data Processing Team, 1989: Nimbus-7 Global Cloud Climatology. Part II: First Year Results. J. Climate, 2, 671–709. [Full text]

Nimbus-7 Global Cloud Climatology. part I: Algorithms and Validation – Stowe et al. (1988) “Data from the Temperature Humidity Infrared Radiometer (THIR) and the Total Ozone Mapping Spectrometer (TOMS), both aboard the Nimbus-7 satellite, are used to determine cloudiness parameters for the globe. The 11.5 μm THIR radiances and the 0.36 μm and 0.38 μm TOMS reflectivities, along with concurrent surface temperature data from the Air Force 3-D nephanalysis, are the primary data sources. They are processed by an algorithm that determines total cloud amount, cloud amount in three altitude categories, cirrus cloud, deep convective cloud, warm cloud, and the radiance of radiation emitted by the clouds. and the underlying surface. The algorithm is of the bispectral threshold type, which yields two independent estimates of total cloud, one from the infrared algorithm and one from the UV reflectivity algorithm. For the daytime observations (local noon at the equator), these two independent estimates are combined to determine a composite estimate, while at night (local midnight at the equator), only the infrared threshold algorithm is used in the estimate. Quantitative validation of total cloud amount was performed by comparing the algorithm results with estimates derived by an analyst interpreting geosynchronous satellite (GOES) images, along with auxiliary meteorological data. It has been concluded that the systematic errors of the Nimbus-7 total cloud amount algorithm relative to the analyst are less than 10%, and that the random errors of daily estimates range between 7% and 16%, day or night. These empirical results are consistent with results from a theoretical sensitivity study. Qualitative validation has also been performed by making comparisons with GOES visible and infrared images for specific days. Results indicate that the TOMS cloud estimates improve the IR algorithm estimates of low cloud amount and provide for the identification of cirrus and deep convective cloud, but cloud amounts over humid tropical regions tend to be overestimated even with the use of TOMS. These results suggest that the spatial and temporal characteristics of daily and monthly averaged global cloud cover, including cirrus acid deep convective cloud types, which are presented in Part II, are generally well represented by the Nimbus-7 dataset, which covers a six-year period from April 1979 to March 1985.” Stowe, L. L., C. G. Wellemeyer, H. Y. M. Yeh, T. F. Eck, The Nimbus-7 CLOUD DATA PROCecessing TEAM, 1988: Nimbus-7 Global Cloud Climatology. part I: Algorithms and Validation. J. Climate, 1, 445–470. [Full text]

Global distribution of total cloud cover and cloud type amounts over the ocean – Warren et al. (1988) “The third atlas (NCAR/TN-273+STR) described, for the land areas of the earth, the average total cloud cover and the amounts of each cloud type, and their geographical, diurnal, seasonal, and interannual variations, as well as the average base heights of the low clouds. The present atlas does the same for the ocean areas of the earth.” [Full text, size of the file is over 20 MB]

Global cloud cover for seasons using TIROS nephanalyses – Clapp (1964) “TIROS nephanalyses are used to obtain global maps and latitudinal profiles of average cloud amount for the four seasons for the year March 1962 through February 1963. It is found that the gross patterns and season-to-season variations of these cloud distributions bear a striking resemblance to corresponding features of normal cloudiness, although there are some differences which call for further study. In many cases anomalies in cloudiness can be related to corresponding anomalies of the general circulation. In considering the magnitude as distinct from the pattern of cloudiness, there is some suggestion that during the chosen period the TIROS nephanalyses gave too much cloudiness for large cloud amount, and too little for small cloud amount.” Clapp, Philip F., 1964, Mon. Wea. Rev., 92, 495–507. [Full text]

Closely related

Comparison of cloud statistics from spaceborne lidar systems – Berthier et al. (2008) This paper relates to the issue of the problems with ISCCP data. “Comparisons of CTH developed from LITE, for 2 weeks of data in 1994, with ISCCP (International Satellite Cloud Climatology Project) cloud products show that the cloud fraction observed from spaceborne lidar is much higher than that from ISCCP. Another key result is that ISCCP products tend to underestimate the CTH of optically thin cirrus clouds.” [Full text]

Quite often claims about global cloud cover trends being responsible for the warming of recent decades are accompanied by claims that cosmic rays are causing them, so this is relevant in that case:
Papers on the non-significant role of cosmic rays in climate

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Papers on the MWP as Global Event

Posted by Ari Jokimäki on September 8, 2009

This list contains papers on the medieval warm period (MWP) with emphasis on global analysis. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

UPDATE (April 22, 2013): Ahmed et al. (2013) added.
UPDATE (April 5, 2012): Diaz et al. (2011) added. Thanks to Barry for pointing it out in papers on reconstructions of modern temperatures.
UPDATE (February 9, 2012): Goosse et al. (2012) added.
UPDATE (January 6, 2012): Zhou et al. (2011) added.
UPDATE (September 20, 2011): Koch & Clague (2011) added. Thanks to Barry for pointing it out, see the comment section below.
UPDATE (June 17, 2011): Graham et al. (2010) added.
UPDATE (August 19, 2010): Ljungqvist (2009) added, thanks to Darius for pointing it out (see the comment section below).
UPDATE (May 17, 2010): Trouet et al. (2009) added.
UPDATE (January 20, 2010): Osborn & Briffa (2006) added.

Continental-scale temperature variability during the past two millennia – Ahmed et al. (2013) “Past global climate changes had strong regional expression. To elucidate their spatio-temporal pattern, we reconstructed past temperatures for seven continental-scale regions during the past one to two millennia. The most coherent feature in nearly all of the regional temperature reconstructions is a long-term cooling trend, which ended late in the nineteenth century. At multi-decadal to centennial scales, temperature variability shows distinctly different regional patterns, with more similarity within each hemisphere than between them. There were no globally synchronous multi-decadal warm or cold intervals that define a worldwide Medieval Warm Period or Little Ice Age, but all reconstructions show generally cold conditions between ad 1580 and 1880, punctuated in some regions by warm decades during the eighteenth century. The transition to these colder conditions occurred earlier in the Arctic, Europe and Asia than in North America or the Southern Hemisphere regions. Recent warming reversed the long-term cooling; during the period ad 1971–2000, the area-weighted average reconstructed temperature was higher than any other time in nearly 1,400 years.” Moinuddin Ahmed, Kevin J. Anchukaitis, Asfawossen Asrat, Hemant P. Borgaonkar, Martina Braida, Brendan M. Buckley, Ulf Büntgen, Brian M. Chase, Duncan A. Christie, Edward R. Cook, Mark A. J. Curran, Henry F. Diaz, Jan Esper, Ze-Xin Fan, Narayan P. Gaire, Quansheng Ge, Joëlle Gergis, J Fidel González-Rouco, Hugues Goosse, Stefan W. Grab, Nicholas Graham, Rochelle Graham, Martin Grosjean, Sami T. Hanhijärvi, Darrell S. Kaufman + et al. Nature Geoscience(2013), doi:10.1038/ngeo1797.

The role of forcing and internal dynamics in explaining the “Medieval Climate Anomaly” – Goosse et al. (2012) “Proxy reconstructions suggest that peak global temperature during the past warm interval known as the Medieval Climate Anomaly (MCA, roughly 950–1250 AD) has been exceeded only during the most recent decades. To better understand the origin of this warm period, we use model simulations constrained by data assimilation establishing the spatial pattern of temperature changes that is most consistent with forcing estimates, model physics and the empirical information contained in paleoclimate proxy records. These numerical experiments demonstrate that the reconstructed spatial temperature pattern of the MCA can be explained by a simple thermodynamical response of the climate system to relatively weak changes in radiative forcing combined with a modification of the atmospheric circulation, displaying some similarities with the positive phase of the so-called Arctic Oscillation, and with northward shifts in the position of the Gulf Stream and Kuroshio currents. The mechanisms underlying the MCA are thus quite different from anthropogenic mechanisms responsible for modern global warming.” Hugues Goosse, Elisabeth Crespin, Svetlana Dubinkina, Marie-France Loutre, Michael E. Mann, Hans Renssen, Yoann Sallaz-Damaz and Drew Shindell, Climate Dynamics, DOI: 10.1007/s00382-012-1297-0.

Spatial and Temporal Characteristics of Climate in Medieval Times Revisited – Diaz et al. (2011) “Developing accurate reconstructions of past climate regimes and enhancing our understanding of the causal factors that may have contributed to their occurrence is important for a number of reasons; these include improvements in the attribution of climate change to natural and anthropogenic forcing, gaining a better appreciation for the range and magnitude of low-frequency variability and previous climatic regimes in comparison with the modern instrumental period, and developing greater insights into the relationship between human society and climatic changes. This paper examine upto- date evidence regarding the characteristics of the climate in medieval times (A.D. ~950–1400). Long and high-resolution climate proxy records reported in the scientific literature, which form the basis for the climate reconstructions, have greatly expanded in the last few decades, with greater numbers of sites that now cover more areas of the globe. Some comparisons with the modern climate record and discussion of potential mechanisms associated with the patterns of medieval climate are presented here, but our main goal is to provide the reader with some appreciation of the richness of past natural climate variability in terms of its spatial and temporal characteristics.” Diaz, Henry F., Ricardo Trigo, Malcolm K. Hughes, Michael E. Mann, Elena Xoplaki, David Barriopedro, 2011: Spatial and Temporal Characteristics of Climate in Medieval Times Revisited. Bull. Amer. Meteor. Soc., 92, 1487–1500. doi: [Full text]

A comparison of the Medieval Warm Period, Little Ice Age and 20th century warming simulated by the FGOALS climate system model – Zhou et al. (2011) “To compare differences among the Medieval Warm Period (MWP), Little Ice Age (LIA), and 20th century global warming (20CW), six sets of transient and equilibrium simulations were generated using the climate system model FGOALS_gl. This model was developed by the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences. The results indicate that MWP warming is evident on a global scale, except for at mid-latitudes of the North Pacific. However, the magnitude of the warming is weaker than that in the 20th century. The warming in the high latitudes of the Northern Hemisphere is stronger than that in the Southern Hemisphere. The LIA cooling is also evident on a global scale, with a strong cooling over the high Eurasian continent, while the cooling center is over the Arctic domain. Both the MWP and the 20CW experiments exhibit the strongest warming anomalies in the middle troposphere around 200–300 hPa, but the cooling center of the LIA experiment is seen in the polar surface of the Northern Hemisphere. A comparison of model simulation against the reconstruction indicates that model’s performance in simulating the surface air temperature changes during the warm periods is better than that during the cold periods. The consistencies between model and reconstruction in lower latitudes are better than those in high latitudes. Comparison of the inter-annual variability mode of East Asian summer monsoon (EASM) rainfall during the MWP, LIA and 20CW reveals a similar rainfall anomalies pattern. However, the time spectra of the principal component during the three typical periods of the last millennium are different, and the quasi-biannual oscillation is more evident during the two warm periods. At a centennial time scale, the external mode of the EASM variability driven by the changes of effective solar radiation is determined by the changes of large scale land-sea thermal contrast. The rainfall anomalies over the east of 110°E exhibit a meridional homogeneous change pattern, which is different from the meridional out-of-phase change of rainfall anomalies associated with the internal mode.” TianJun Zhou, Bo Li, WenMin Man, LiXia Zhang and Jie Zhang, Chinese Science Bulletin, Volume 56, Numbers 28-29, 3028-3041, DOI: 10.1007/s11434-011-4641-6. [Full text]

Extensive glaciers in northwest North America during Medieval time – Koch & Clague (2011) “The Medieval Warm Period is an interval of purportedly warm climate during the early part of the past millennium. The duration, areal extent, and even existence of the Medieval Warm Period have been debated; in some areas the climate of this interval appears to have been affected more by changes in precipitation than in temperature. Here, we provide new evidence showing that several glaciers in western North America advanced during Medieval time and that some glaciers achieved extents similar to those at the peak of the Little Ice Age, many hundred years later. The advances cannot be reconciled with a climate similar to that of the twentieth century, which has been argued to be an analog, and likely were the result of increased winter precipitation due to prolonged La Niña-like conditions that, in turn, may be linked to elevated solar activity. Changes in solar output may initiate a response in the tropical Pacific that directly impacts the El Niño/Southern Oscillation and associated North Pacific teleconnections.” Johannes Koch and John J. Clague, Climatic Change, Volume 107, Numbers 3-4, 593-613, DOI: 10.1007/s10584-010-0016-2.

Support for global climate reorganization during the “Medieval Climate Anomaly” – Graham et al. (2010) “Widely distributed proxy records indicate that the Medieval Climate Anomaly (MCA; ~900–1350 AD) was characterized by coherent shifts in large-scale Northern Hemisphere atmospheric circulation patterns. Although cooler sea surface temperatures in the central and eastern equatorial Pacific can explain some aspects of medieval circulation changes, they are not sufficient to account for other notable features, including widespread aridity through the Eurasian sub-tropics, stronger winter westerlies across the North Atlantic and Western Europe, and shifts in monsoon rainfall patterns across Africa and South Asia. We present results from a full-physics coupled climate model showing that a slight warming of the tropical Indian and western Pacific Oceans relative to the other tropical ocean basins can induce a broad range of the medieval circulation and climate changes indicated by proxy data, including many of those not explained by a cooler tropical Pacific alone. Important aspects of the results resemble those from previous simulations examining the climatic response to the rapid Indian Ocean warming during the late twentieth century, and to results from climate warming simulations—especially in indicating an expansion of the Northern Hemisphere Hadley circulation. Notably, the pattern of tropical Indo-Pacific sea surface temperature (SST) change responsible for producing the proxy-model similarity in our results agrees well with MCA-LIA SST differences obtained in a recent proxy-based climate field reconstruction. Though much remains unclear, our results indicate that the MCA was characterized by an enhanced zonal Indo-Pacific SST gradient with resulting changes in Northern Hemisphere tropical and extra-tropical circulation patterns and hydroclimate regimes, linkages that may explain the coherent regional climate shifts indicated by proxy records from across the planet. The findings provide new perspectives on the nature and possible causes of the MCA—a remarkable, yet incompletely understood episode of Late Holocene climatic change.” N. E. Graham, C. M. Ammann, D. Fleitmann, K. M. Cobb and J. Luterbacher, Climate Dynamics, DOI: 10.1007/s00382-010-0914-z. [Full text]

Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly – Mann et al. (2009) “Global temperatures are known to have varied over the past 1500 years, but the spatial patterns have remained poorly defined. We used a global climate proxy network to reconstruct surface temperature patterns over this interval. The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally.” [Link to PDF]

Centennial Variations of the Global Monsoon Precipitation in the Last Millennium: Results from ECHO-G Model – Liu et al. (2009) “The authors investigate how the global monsoon (GM) precipitation responds to the external and anthropogenic forcing in the last millennium by analyzing a pair of control and forced millennium simulations with the ECHAM and the global Hamburg Ocean Primitive Equation (ECHO-G) coupled ocean–atmosphere model. … Conversely, strong GM was simulated during the model Medieval Warm Period (ca. 1030–1240). … The simulated change of GM in the last 30 yr has a spatial pattern that differs from that during the Medieval Warm Period, suggesting that global warming that arises from the increases of greenhouse gases and the input solar forcing may have different effects on the characteristics of GM precipitation.”

Persistent Positive North Atlantic Oscillation Mode Dominated the Medieval Climate Anomaly – Trouet et al. (2009) “The Medieval Climate Anomaly (MCA) was the most recent pre-industrial era warm interval of European climate, yet its driving mechanisms remain uncertain. We present here a 947-year-long multidecadal North Atlantic Oscillation (NAO) reconstruction and find a persistent positive NAO during the MCA. Supplementary reconstructions based on climate model results and proxy data indicate a clear shift to weaker NAO conditions into the Little Ice Age (LIA). Globally distributed proxy data suggest that this NAO shift is one aspect of a global MCA-LIA climate transition that probably was coupled to prevailing La Niña–like conditions amplified by an intensified Atlantic meridional overturning circulation during the MCA.” [Full text]

Temperature proxy records covering the last two millenia: a tabular and visual overview – Ljungqvist (2009) “Here, the first systematic survey is presented, with graphic representations, of most quantitative temperature proxy data records covering the last two millennia that have been published in the peer-reviewed literature. In total, 71 series are presented together with basic essential information on each record. This overview will hopefully assist future palaeoclimatic research by facilitating an orientation among available palaeotemperature records and thus reduce the risk of missing less well-known proxy series. The records show an amplitude between maximum and minimum temperatures during the past two millennia on centennial timescales ranging from c. 0.5 to 4°C and averaging c. 1.5–2°C for both high and low latitudes, although these variations are not always occurring synchronous. Both the Medieval Warm Period, the Little Ice Age and the 20th century warming are clearly visible in most records, whereas the Roman Warm Period and the Dark Age Cold Period are less clearly discernible.”

How the Rate of Volcanism Initiated the Medieval Warm Period and Controlled Its Periods of Drought – Ward (2008) “During the Medieval Warm Period, most large volcanic eruptions are contemporaneous with short-term decreases in Northern Hemisphere temperature determined using high-resolution proxy data (Mann and Jones, 2003). When such large eruptions occur more frequently than every few years, however, the oxidizing capacity of the atmosphere is exceeded, greenhouse gases accumulate, and the earth warms. … Only 27% of these ice layers contained “volcanic” sulfate and there were only 3 instances where more than 6 contiguous layers contained “volcanic” sulfate: 179-140 BC (16 layers), the onset of the Roman Climate Optimum, 818-840 AD (11 layers), the onset of the Medieval Warm Period, and 1929-1984 AD (34 layers), the onset of the modern warming period caused by anthropogenic SO2.” [Presentation material 1, Presentation material 2]

Blueprints for Medieval hydroclimate – Seager et al. (2007) “A review of proxy evidence from around the world indicates that North American megadroughts were part of a global pattern of Medieval hydroclimate that was distinct from that of today. … A positive North Atlantic Oscillation (NAO) also helps to explain the Medieval hydroclimate pattern. … Tentative modeling results indicate that a multi-century La Niña-like state could have arisen as a coupled atmosphere–ocean response to high irradiance and weak volcanism during the Medieval period and that this could in turn have induced a persistently positive NAO state.” [Link to PDF]

The Spatial Extent of 20th-Century Warmth in the Context of the Past 1200 Years – Osborn & Briffa (2006) “Positive anomalies during 890 to 1170 and negative anomalies during 1580 to 1850 are consistent with the concepts of a Medieval Warm Period and a Little Ice Age, but comparison with instrumental temperatures shows the spatial extent of recent warmth to be of greater significance than that during the medieval period.” [Link to PDF]

A late medieval warm period in the Southern Ocean as a delayed response to external forcing? – Goosse et al. (2004) “On the basis of long simulations performed with a three-dimensional climate model, we propose an interhemispheric climate lag mechanism, involving the long-term memory of deepwater masses. Warm anomalies, formed in the North Atlantic when warm conditions prevail at surface, are transported by the deep ocean circulation towards the Southern Ocean. There, the heat is released because of large scale upwelling, maintaining warm conditions and inducing a lagged response of about 150 years compared to the Northern Hemisphere. Model results and observations covering the first half of the second millenium suggest a delay between the temperature evolution in the Northern Hemisphere and in the Southern Ocean. The mechanism described here provides a reasonable hypothesis to explain such an interhemipsheric lag.” [Link to PDF]

Climate in Medieval Time – Bradley et al. (2003) “although the High Medieval (1100 to 1200 A.D.) was warmer than subsequent centuries, it was not warmer than the late 20th century. Moreover, the warmest Medieval temperatures were not synchronous around the globe. Large changes in precipitation patterns are a particular characteristic of “High Medieval” time.”

Medieval Climatic Optimum – Mann (2002) “Thus, current evidence does not support the notion of a Medieval Climatic Optimum as an interval of hemispheric or global warmth comparable to the latter 20th century.” [Link to PDF]

Was the Medieval Warm Period Global? – Broecker (2001) “During the Medieval Warm Period (800 to 1200 A.D.), the Vikings colonized Greenland. In his Perspective, Broecker discusses whether this warm period was global or regional in extent. He argues that it is the last in a long series of climate fluctuations in the North Atlantic, that it was likely global, and that the present warming should be attributed in part to such an oscillation, upon which the warming due to greenhouse gases is superimposed.” [Link to PDF]

How Warm Was the Medieval Warm Period? – Crowley & Lowery (2000) “Despite clear evidence for Medieval warmth greater than present in some individual records, the new hemispheric composite supports the principal conclusion of earlier hemispheric reconstructions and, furthermore, indicates that maximum Medieval warmth was restricted to two-three 20–30 year intervals, with composite values during these times being only comparable to the mid-20 th century warm time interval. Failure to substantiate hemispheric warmth greater than the present consistently occurs in composites because there are significant offsets in timing of warmth in different regions; ignoring these offsets can lead to serious errors concerning inferences about the magnitude of Medieval warmth and its relevance to interpretation of late 20 th century warming.” [Link to PDF]

Was there a ‘medieval warm period’, and if so, where and when? – Hughes & Diaz (1994) “Our review indicates that for some areas of the globe (for example, Scandinavia, China, the Sierra Nevada in California, the Canadian Rockies and Tasmania), temperatures, particularly in summer, appear to have been higher during some parts of this period than those that were to prevail until the most recent decades of the twentieth century. These warmer regional episodes were not strongly synchronous. Evidence from other regions (for example, the Southeast United States, southern Europe along the Mediterranean, and parts of South America) indicates that the climate during that time was little different to that of later times, or that warming, if it occurred, was recorded at a later time than has been assumed. Taken together, the available evidence does not support a global Medieval Warm Period, although more support for such a phenomenon could be drawn from high-elevation records than from low-elevation records.” [Link to PDF]

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