AGW Observer

Observations of anthropogenic global warming

New research from last week 17/2011

Posted by Ari Jokimäki on May 2, 2011

Here is the new research published last week. I’m not including everything that was published but just some papers that got my attention. Those who follow my Facebook page (and/or Twitter) have already seen most of these, as I post these there as soon as they are published. Here, I’ll just put them out in one batch. Sometimes I might also point out to some other news as well, but the new research will be the focus here. Here’s the archive for the news of previous weeks. By the way, if this sort of thing interests you, be sure to check out A Few Things Illconsidered, they have a weekly posting containing lots of links to new research and other climate related news. Planet 3.0 also reports new research.

Published last week:

Good news! Global warming improves fossil preservation

Exceptional fossil preservation during CO2 greenhouse crises? – Retallack (2011) “Exceptional fossil preservation may require not only exceptional places, but exceptional times, as demonstrated here by two distinct types of analysis. First, irregular stratigraphic spacing of horizons yielding articulated Triassic fishes and Cambrian trilobites is highly correlated in sequences in different parts of the world, as if there were short temporal intervals of exceptional preservation globally. Second, compilations of ages of well-dated fossil localities show spikes of abundance which coincide with stage boundaries, mass extinctions, oceanic anoxic events, carbon isotope anomalies, spikes of high atmospheric carbon dioxide, and transient warm-wet paleoclimates. Exceptional fossil preservation may have been promoted during unusual times, comparable with the present: CO2 greenhouse crises of expanding marine dead zones, oceanic acidification, coral bleaching, wetland eutrophication, sea level rise, ice-cap melting, and biotic invasions.” Gregory J. Retallack, Palaeogeography, Palaeoclimatology, Palaeoecology, doi:10.1016/j.palaeo.2011.04.023.

Temperature extremes in China since 1960

Observed changes of temperature extremes during 1960–2005 in China: natural or human-induced variations? – Zhang et al. (2011) “The purpose of this study was to statistically examine changes of surface air temperature in time and space and to analyze two factors potentially influencing air temperature changes in China, i.e., urbanization and net solar radiation. Trends within the temperature series were detected by using Mann-Kendall trend test technique. The scientific problem this study expected to address was that what could be the role of human activities in the changes of temperature extremes. Other influencing factors such as net solar radiation were also discussed. The results of this study indicated that: (1) increasing temperature was observed mainly in the northeast and northwest China; (2) different behaviors were identified in the changes of maximum and minimum temperature respectively. Maximum temperature seemed to be more influenced by urbanization, which could be due to increasing urban albedo, aerosol, and air pollutions in the urbanized areas. Minimum temperature was subject to influences of variations of net solar radiation; (3) not significant increasing and even decreasing temperature extremes in the Yangtze River basin and the regions south to the Yangtze River basin could be the consequences of higher relative humidity as a result of increasing precipitation; (4) the entire China was dominated by increasing minimum temperature. Thus, we can say that the warming process of China was reflected mainly by increasing minimum temperature. In addition, consistently increasing temperature was found in the upper reaches of the Yellow River basin, the Yangtze River basin, which have the potential to enhance the melting of permafrost in these areas. This may trigger new ecological problems and raise new challenges for the river basin scale water resource management.” Qiang Zhang, Jianfeng Li, Yongqin David Chen and Xiaohong Chen, Theoretical and Applied Climatology, DOI: 10.1007/s00704-011-0447-3.

Analysis of Russian 2010 heatwave

The Central European and Russian Heat Event of July-August 2010 – Grumm (2011) No abstract. “This paper will document the large scale conditions associated with the eastern European and Russian heat wave of July-August 2010. The focus is on an analysis of anomalies associated with key features.” Richard H. Grumm, Bulletin of the American Meteorological Society 2011, doi: 10.1175/2011BAMS3174.1. [Full text]

Tree species among saplings change with global warming

Changes in tree sapling composition within powerline corridors appear to be consistent with climatic changes in New York State – Treyger & Nowak (2011) “Despite emerging evidence that on-going climate change is affecting species physiology, distribution, and phenology, there are few studies that examine changes in tree sapling establishment as a response. Changes in tree species composition can be expected due to increasing temperatures, with subsequent effects on future forest compositions. This study’s objective was to examine changes in relative density of tree species assemblages within powerline corridors from 1975–2003 in New York State. Powerline corridors in New York are commonly surrounded by forests, which creates constant tree invasion pressure within a perpetual old-field environment. This unique combination of factors allowed us to examine tree sapling establishment in a nearly constant environment over a 28-year period, utilizing manova and PCA as primary statistical analyses. Tree species dynamics varied across the four ecological provinces within New York over time. Northern pioneer species (Betula populifolia, Fraxinus americana, Prunus serotina, and Tilia americana) declined across the state over the past 28 years, while the southern pioneer species (Betula lenta, Liriodendron tulipifera, and Sassafras albidum) increased in the hot continental division. In the warm continental division, the pine-hemlock assemblage increased in the Northeastern Mixed Forest Province, while aspen-birch increased in the Adirondack Highlands Forest Province, likely due to increases in precipitation. It appears that climate change may have had some influence on tree sapling composition that could affect future vegetation management decisions and expectations in powerline rights-of-way and forests.” Artem L. Treyger, Christopher A. Nowak, Global Change Biology, DOI: 10.1111/j.1365-2486.2011.02455.x.

Even in warming world there will be extreme cold events

Persisting cold extremes under 21st-century warming scenarios – Kodra et al. (2011) “Analyses of climate model simulations and observations reveal that extreme cold events are likely to persist across each land-continent even under 21st-century warming scenarios. The grid-based intensity, duration and frequency of cold extreme events are calculated annually through three indices: the coldest annual consecutive three-day average of daily maximum temperature, the annual maximum of consecutive frost days, and the total number of frost days. Nine global climate models forced with a moderate greenhouse-gas emissions scenario compares the indices over 2091–2100 versus 1991–2000. The credibility of model-simulated cold extremes is evaluated through both bias scores relative to reanalysis data in the past and multi-model agreement in the future. The number of times the value of each annual index in 2091–2100 exceeds the decadal average of the corresponding index in 1991–2000 is counted. The results indicate that intensity and duration of grid-based cold extremes, when viewed as a global total, will often be as severe as current typical conditions in many regions, but the corresponding frequency does not show this persistence. While the models agree on the projected persistence of cold extremes in terms of global counts, regionally, inter-model variability and disparity in model performance tends to dominate. Our findings suggest that, despite a general warming trend, regional preparedness for extreme cold events cannot be compromised even towards the end of the century.” Kodra, E., K. Steinhaeuser, and A. R. Ganguly (2011), Persisting cold extremes under 21st-century warming scenarios, Geophys. Res. Lett., 38, L08705, doi:10.1029/2011GL047103.

Future of snow in North-Europe

21st Century changes in snow climate in Northern Europe: a high-resolution view from ENSEMBLES regional climate models – Räisänen & Eklund (2011) “Changes in snow amount in northern Europe are analysed from 11 regional model simulations of 21st century climate under the Special Report on Emissions Scenarios A1B scenario. These high-resolution models collectively indicate a future decrease in the water equivalent of the snow pack (SWE). Although winter precipitation increases, this is insufficient to compensate for the increased fraction of liquid precipitation and increased snowmelt caused by higher temperatures. The multi-model mean results suggest a slight increase in March mean SWE only locally in mountains of northern Sweden, and even there, snow is reduced earlier in winter and later in spring. The nature of the changes remains the same throughout the 21st century, but their magnitude increases with time as the greenhouse gas forcing grows larger. The geographical patterns of the change support the physically intuitive view that snow is most vulnerable to warming in areas with relatively mild winter climate. A similar relationship emerges when comparing the 11 simulations with each other: the ratio between the relative SWE decrease and winter mean temperature change is larger (smaller) for simulations with higher (lower) late 20th century winter temperatures. Despite the decrease in long-term mean SWE, individual snow-rich winters do occur in the simulations, but they become increasingly uncommon towards the end of the 21st century.” Jouni Räisänen and Joonas Eklund, Climate Dynamics, DOI: 10.1007/s00382-011-1076-3.

When sea level rises, rice price rises

Climate change, sea level rise and rice: global market implications – Chen et al. (2011) “Climate change will influence yields while sea level rise can inundate producing lands. The research reported investigates the individual and simultaneous effects of these factors on production, trade and consumption of rice the world’s number one food crop. A global rice trade model is utilized to do this. The results indicate that the combination of yield and sea level effects causes a significant reduction in production and an increase in rice prices which may have important policy implications for food security. Global rice production is reduced by 1.60% to 2.73% while global rice price increases by 7.14% to 12.77%. Sea level rise is particularly a risk factor in Bangladesh, Japan, Taiwan, Egypt, Myanmar and Vietnam. In the face of such developments, adaptation may well be desirable and thus an investigation is done over adaptation options of increased technical progress or trade liberalization with the results showing that both can mitigate such damages.” Chi-Chung Chen, Bruce McCarl and Ching-Cheng Chang, Climatic Change, DOI: 10.1007/s10584-011-0074-0.


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