Papers on minor role of the Sun in recent climate change
Posted by Ari Jokimäki on September 3, 2009
NOTE! There is a new version of this paperlist: Papers on the role of the Sun in recent global warming.
This list contains papers that show Sun’s role to be minor in the recent climate change. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.
LATEST UPDATE (April 18, 2012): Stauning (2011) added. Thanks to Barry for pointing it out.
Solar activity–climate relations: A different approach – Stauning (2011) “The presentation of solar activity–climate relations is extended with the most recent sunspot and global temperature data series. The extension of data series shows clearly that the changes in terrestrial temperatures are related to sources different from solar activity after ∼1985. Based on analyses of data series for the years 1850–1985 it is demonstrated that, apart from an interval of positive deviation followed by a similar negative excursion in Earth’s temperatures between ∼1923 and 1965, there is a strong correlation between solar activity and terrestrial temperatures delayed by 3 years, which complies with basic causality principles. A regression analysis between solar activity represented by the cycle-average sunspot number, SSNA, and global temperature anomalies, ΔTA, averaged over the same interval lengths, but delayed by 3 years, provides the relation ΔTA∼0.009 (±0.002) SSNA. Since the largest ever observed SSNA is ∼90 (in 1954–1965), the solar activity-related changes in global temperatures could amount to no more than ±0.4 °C over the past ∼400 years where the sunspots have been recorded. It is demonstrated that the small amplitudes of cyclic variations in the average global temperatures over the ∼11 year solar cycle excludes many of the various driver processes suggested in published and frequently quoted solar activity–climate relations. It is suggested that the in-cycle variations and also the longer term variations in global temperatures over the examined 135 years are mainly caused by corresponding changes in the total solar irradiance level representing the energy output from the core, but further modulated by varying energy transmission properties in the active outer regions of the Sun.” P. Stauning, Journal of Atmospheric and Solar-Terrestrial Physics, Volume 73, Issue 13, August 2011, Pages 1999–2012, http://dx.doi.org/10.1016/j.jastp.2011.06.011.
Are secular correlations between sunspots, geomagnetic activity, and global temperature significant? – Love et al. (2011) “Recent studies have led to speculation that solar-terrestrial interaction, measured by sunspot number and geomagnetic activity, has played an important role in global temperature change over the past century or so. We treat this possibility as an hypothesis for testing. We examine the statistical significance of cross-correlations between sunspot number, geomagnetic activity, and global surface temperature for the years 1868–2008, solar cycles 11–23. The data contain substantial autocorrelation and nonstationarity, properties that are incompatible with standard measures of cross-correlational significance, but which can be largely removed by averaging over solar cycles and first-difference detrending. Treated data show an expected statistically-significant correlation between sunspot number and geomagnetic activity, Pearson p < 10−4, but correlations between global temperature and sunspot number (geomagnetic activity) are not significant, p = 0.9954, (p = 0.8171). In other words, straightforward analysis does not support widely-cited suggestions that these data record a prominent role for solar-terrestrial interaction in global climate change. With respect to the sunspot-number, geomagnetic-activity, and global-temperature data, three alternative hypotheses remain difficult to reject: (1) the role of solar-terrestrial interaction in recent climate change is contained wholly in long-term trends and not in any shorter-term secular variation, or, (2) an anthropogenic signal is hiding correlation between solar-terrestrial variables and global temperature, or, (3) the null hypothesis, recent climate change has not been influenced by solar-terrestrial interaction.” Love, J. J., K. Mursula, V. C. Tsai, and D. M. Perkins (2011), Geophys. Res. Lett., 38, L21703, doi:10.1029/2011GL049380. [Full text]
An influence of solar spectral variations on radiative forcing of climate – Haigh et al. (2010) “The thermal structure and composition of the atmosphere is determined fundamentally by the incoming solar irradiance. Radiation at ultraviolet wavelengths dissociates atmospheric molecules, initiating chains of chemical reactions—specifically those producing stratospheric ozone—and providing the major source of heating for the middle atmosphere, while radiation at visible and near-infrared wavelengths mainly reaches and warms the lower atmosphere and the Earth’s surface. Thus the spectral composition of solar radiation is crucial in determining atmospheric structure, as well as surface temperature, and it follows that the response of the atmosphere to variations in solar irradiance depends on the spectrum. Daily measurements of the solar spectrum between 0.2 µm and 2.4 µm, made by the Spectral Irradiance Monitor (SIM) instrument on the Solar Radiation and Climate Experiment (SORCE) satellite since April 2004, have revealed that over this declining phase of the solar cycle there was a four to six times larger decline in ultraviolet than would have been predicted on the basis of our previous understanding. This reduction was partially compensated in the total solar output by an increase in radiation at visible wavelengths. Here we show that these spectral changes appear to have led to a significant decline from 2004 to 2007 in stratospheric ozone below an altitude of 45 km, with an increase above this altitude. Our results, simulated with a radiative-photochemical model, are consistent with contemporaneous measurements of ozone from the Aura-MLS satellite, although the short time period makes precise attribution to solar effects difficult. We also show, using the SIM data, that solar radiative forcing of surface climate is out of phase with solar activity. Currently there is insufficient observational evidence to validate the spectral variations observed by SIM, or to fully characterize other solar cycles, but our findings raise the possibility that the effects of solar variability on temperature throughout the atmosphere may be contrary to current expectations.” Joanna D. Haigh, Ann R. Winning, Ralf Toumi & Jerald W. Harder, Nature, Volume: 467, Pages: 696–699, Date published: 07 October 2010, doi:10.1038/nature09426. [Full text]
Solar change and climate: an update in the light of the current exceptional solar minimum – Lockwood (2010) “Solar outputs during the current solar minimum are setting record low values for the space age. Evidence is here reviewed that this is part of a decline in solar activity from a grand solar maximum and that the Sun has returned to a state that last prevailed in 1924. Recent research into what this means, and does not mean, for climate change is reviewed.” [Full text]
Cycles and trends in solar irradiance and climate – Lean (2009) “Claims that the Sun has caused as much as 70% of the recent global warming (based in part on the attribution of radiometric trends to real solar irradiance changes) presents fundamental puzzles. It requires that the Sun’s brightness increased more in the past century than at any time in the past millennium, including over the past 30 years, contrary to the direct space-based observations. And it requires, as well, that Earth’s climate be insensitive to well-measured increases in greenhouse gases at the same time that it is excessively sensitive to poorly known solar brightness changes. Both scenarios are far less plausible than the simple attribution of most (90%) industrial global warming to anthropogenic effects, rather than to the Sun.” [Full text]
Solar trends and global warming – Benestad & Schmidt (2009) “We use a suite of global climate model simulations for the 20th century to assess the contribution of solar forcing to the past trends in the global mean temperature. … We also demonstrate that the methodologies used by Scafetta and West (2005, 2006a, 2006b, 2007, 2008) are not robust to these same factors and that their error bars are significantly larger than reported. Our analysis shows that the most likely contribution from solar forcing a global warming is 7 ± 1% for the 20th century and is negligible for warming since 1980.” [Full text]
Total solar irradiance variability: What have we learned about its variability from the record of the last three solar cycles? – Fröhlich (2009) “Presently, there are three TSI composites available, called PMOD, ACRIM and IRMB, which are all constructed from the same original data, but use different procedures to correct for sensitivity changes. The PMOD composite is the only one which also corrects the early HF data for degradation. The origin of the differences between the three composite are discussed by comparison with the record of ERBE.” [Full text]
Recent changes in solar outputs and the global mean surface temperature. III. Analysis of contributions to global mean air surface temperature rise – Lockwood (2008) “It is shown that the contribution of solar variability to the temperature trend since 1987 is small and downward; the best estimate is −1.3% and the 2σ confidence level sets the uncertainty range of −0.7 to −1.9%. The result is the same if one quantifies the solar variation using galactic cosmic ray fluxes (for which the analysis can be extended back to 1953) or the most accurate total solar irradiance data composite.” [Full text]
Recent oppositely directed trends in solar climate forcings and the global mean surface air temperature. II. Different reconstructions of the total solar irradiance variation and dependence on response time scale – Lockwood & Fröhlich (2008) “Use of the ACRIM composite, which shows a rise in TSI over recent decades, is shown to be inconsistent with most published evidence for solar influences on pre-industrial climate. The conclusions of our previous paper, that solar forcing has declined over the past 20 years while surface air temperatures have continued to rise, are shown to apply for the full range of potential time constants for the climate response to the variations in the solar forcings.” [Full text]
Recent oppositely directed trends in solar climate forcings and the global mean surface air temperature – Lockwood & Fröhlich (2007) “Here we show that over the past 20 years, all the trends in the Sun that could have had an influence on the Earth’s climate have been in the opposite direction to that required to explain the observed rise in global mean temperatures.” [Full text]
Variations in solar luminosity and their effect on the Earth’s climate – Foukal et al. (2006) “In this Review, we show that detailed analysis of these small output variations has greatly advanced our understanding of solar luminosity change, and this new understanding indicates that brightening of the Sun is unlikely to have had a significant influence on global warming since the seventeenth century.” [Full text]
A review of the solar cycle length estimates – Benestad (2005) “There have been speculations about an association between the solar cycle length and Earth’s climate, however, the solar cycle length analysis does not follow Earth’s global mean surface temperature. A further comparison with the monthly sunspot number, cosmic galactic rays and 10.7 cm absolute radio flux since 1950 gives no indication of a systematic trend in the level of solar activity that can explain the most recent global warming.”
Can solar variability explain global warming since 1970? – Solanki & Krivova (2003) “The solar records are scaled such that statistically the solar contribution to climate is as large as possible in this period. Under this assumption we repeat the comparison but now including the period 1970–1999. This comparison shows without requiring any recourse to modeling that since roughly 1970 the solar influence on climate (through the channels considered here) cannot have been dominant. In particular, the Sun cannot have contributed more than 30% to the steep temperature increase that has taken place since then, irrespective of which of the three considered channels is the dominant one determining Sun-climate interactions: tropospheric heating caused by changes in total solar irradiance, stratospheric chemistry influenced by changes in the solar UV spectrum, or cloud coverage affected by the cosmic ray flux.” [Full text]
The Sun’s Role in Climate Variations – Rind (2002) A review paper. “Is the Sun the controller of climate changes, only the instigator of changes that are mostly forced by the system feedbacks, or simply a convenient scapegoat for climate variations lacking any other obvious cause? This question is addressed for suggested solar forcing mechanisms operating on time scales from billions of years to decades. Each mechanism fails to generate the expected climate response in important respects, although some relations are found. The magnitude of the system feedbacks or variability appears as large or larger than that of the solar forcing, making the Sun’s true role ambiguous.” [Full text]
The effects of solar variability on the Earth’s climate – Haigh (2002) A review paper. “Observational data suggest that the Sun has influenced temperatures on decadal, centennial and millennial time-scales, but radiative forcing considerations and the results of energy-balance models and general circulation models suggest that the warming during the latter part of the 20th century cannot be ascribed entirely to solar effects.” [Full text]
The Sun’s total irradiance: Cycles, trends and related climate change uncertainties since 1976 – Fröhlich & Lean (1998) “A composite record of the Sun’s total irradiance compiled from measurements made by five independent space‐based radiometers since 1978 exhibits a prominent 11‐year cycle with similar levels during 1986 and 1996, the two most recent minimum epochs of solar activity. This finding contradicts recent assertions of a 0.04% irradiance increase from the 1986 to 1996 solar minima and suggests that solar radiative output trends contributed little of the 0.2°C increase in the global mean surface temperature in the past decade.” [Full text]
Dependence of global temperatures on atmospheric CO2 and solar irradiance – Thomson (1997) “I estimate transfer functions from changes in atmospheric CO2 and from changes in solar irradiance to hemispheric temperatures that have been corrected for the effects of precession. They show that changes from CO2 over the last century are about three times larger than those from changes in solar irradiance. The increase in global average temperature during the last century is at least 20 times the SD of the residual temperature series left when the effects of CO2 and changes in solar irradiance are subtracted.” [Full text]
The Seasons, Global Temperature, and Precession – Thomson (1995) “Coherence between changes in the amplitude of the annual cycle and those in the average temperature show that between 1854 and 1922 there were small temperature variations, probably of solar origin. Since 1922, the phase of the Northern Hemisphere coherence between these quantities switched from 0° to 180° and implies that solar variability cannot be the sole cause of the increasing temperature over the last century. About 1940, the phase patterns of the previous 300 years began to change and now appear to be changing at an unprecedented rate. The average change in phase is now coherent with the logarithm of atmospheric CO2 concentration.”
There are also many papers suggesting stronger role for the Sun in recent climate change, such as Scafetta & West (2006) included in Nils Simon’s collection, which contains also some other papers not listed here.
UPDATE (November 16, 2011): Love et al. (2011) added.
UPDATE (October 15, 2010): Haigh et al. (2010) added. Thanks to Barry for pointing it out, see the comment section below.
UPDATE (April 11, 2010): Thomson (1995) and Thomson (1997) added.
UPDATE (March 9, 2010): Lean (2009) added, thanks to PeterPan for pointing it out, see the comment section below.
UPDATE (February 19, 2010): Lockwood (2009) is now Lockwood (2010) because it wasn’t officially published until now.
UPDATE (January 14, 2010): Lockwood (2009) added, thanks to Matti for pointing it out.
UPDATE (December 15, 2009): Full text link to Benestad & Schmidt (2009) added, thanks to PeterPan for pointing it out, see the comment section below.
UPDATE (December 9, 2009): Benestad & Schmidt (2009) added.
UPDATE (October 26, 2009): Benestad (2005) added. Thanks to PeterPan for pointing it out, see the comment section below.
UPDATE (September 15, 2009): Some time ago I added Foukal et al. (2006) but forgot to make the update note about it. Nils Simon pointed out his collection of papers (thanks Nils) where I found this paper. I also added a note in the “closely related” section.