Summary: Skeptic websites are agog with confident statements that solar cycles drive much of the decadal variation in Earth’s climate. Not only is there no clear physical mechanism, but recent analysis suggests that the historical correlation might not exist as well. Both questions lie on the frontier of science. Here are some recent papers, a selection from the vast and rapidly growing body of research on the frontiers of knowledge about this vital subject. As past comments to thei series show, true believers on both sides of the climate wars react to real science like vampires to holy water. This is the sixth in a series of posts; at the end are links to the other chapters.
This post looks at only the contrary research, that suggesting small solar effects. This debate lies on the cutting edge of solar and climate sciences. And it is a debate. Unlike the child-like views of most websites discussing climate issues, where there are only skins and shirts, right and wrong views, the FM website helps you understand both sides in these debates. Red emphasis added.
- Solar forcings of global temperatures: not big
- Solar forcing of global temperature: a small fraction of the total
- Solar trends effect on global warming: negligible
- Effect of a new grand minimum of solar activity on the future climate on Earth: small
- On the other hand, there is another side to the debate
- Effect of cosmic rays on global temperatures
- Solar effects on global temperature: not supported by the data
- We cannot know the effects of solar variation since experts cannot agree on the solar record
- Variations in Solar Irradiance — and Climate
- Other chapters in this series
- For more information: other posts about the solar cycle
(1) Solar forcings of global temperatures: not big
“How Natural and Anthropogenic Influences Alter Global and Regional Surface Temperatures: 1889 to 2006″, Judith L. Lean and David H. Rind, Geophysical Research Letters, 16 September 2008 — Free copy here. Conclusion:
None of the natural processes can account for the overall warming trend in global surface temperatures. In the 100 years from 1905 to 2005, the temperature trends produce by all 3 natural influences are at least an order of magnitude smaller than the observed surface temperature trend reported by IPCC . According to this analysis, solar forcing contributed negligible long-term warming in the past 25 years and 10% of the warming in the past 100 years, not 69% as claimed by Scafetta and West  (who assumed larger solar irradiance changes and enhanced climate response on longer time scales).
(2) Solar forcing of global temperature: a small fraction of the total
“Solar activity and the mean global temperature”, A D Erlykin, Environmental Research Letters, 20 January 2009 — Abstract: