A well-referenced paper by Syun-Ichi Akasofu, International Arctic Research Center, University of Alaska Fairbanks, contends that 20th Century warming can be explained as a linear recovery from the “Little Ice Age (LIA)” as modified by solar-induced multi-decadal oscillations. The author notes that the recovery since the end of the LIA in about 1850 has proceeded at the rate of 0.5°C/century and is expected to continue at least until the year 2100. The author predicts that global temperature increase to 2100 will be “0.5°C ± 0.2° C, rather than 4° C ± 2.0° C predicted by the IPCC.”
This paper contains many interesting graphics and provides a good short summary of natural variation and the evidence for such variation. The author does not find any evidence of influence by carbon dioxide emissions. In fact, the author debunks some of the supposed evidence used to support the greenhouse effect.
The abstract reads:
A number of published papers and openly available data on sea level changes, glacier retreat, freezing/break-up dates of rivers, sea ice retreat, tree-ring observations, ice cores and changes of the cosmic-ray intensity, from the year 1000 to the present, are studied to examine how the Earth has recovered from the Little Ice Age (LIA). We learn that the recovery from the LIA has proceeded continuously, roughly in a linear manner, from 1800-1850 to the present. The rate of the recovery in terms of temperature is about 0.5°C/100 years and thus it has important implications for understanding the present global warming. It is suggested on the basis of a much longer period covering that the Earth is still in the process of recovery from the LIA; there is no sign to indicate the end of the recovery before 1900. Cosmic-ray intensity data show that solar activity was related to both the LIA and its recovery. The multi-decadal oscillation of a period of 50 to 60 years was superposed on the linear change; it peaked in 1940 and 2000, causing the halting of warming temporarily after 2000. These changes are natural changes, and in order to determine the contribution of the manmade greenhouse effect, there is an urgent need to identify them correctly and accurately and remove them from the present global warming/cooling trend.
Akasofu, S.-I. 2010. On the recovery from the Little Ice Age. Natural Science 2: 1211-1224.
[Link to full paper, click on Full Text]