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In a preprint paper published today on the Los Alamos astro-ph website and accepted for publication in the Journal of Atmospheric and Solar-Terrestrial Physics, Norwegian scientists have found a strong correlation between the length of the solar sunspot cycle and the Earth’s temperature during the following cycle. From the abstract:
Relations between the length of a sunspot cycle and the average temperature in the same and the next cycle are calculated for a number of meteorological stations in Norway and in the North Atlantic region. No significant trend is found between the length of a cycle and the average temperature in the same cycle, but a significant negative trend is found between the length of a cycle and the temperature in the next cycle. This provides a tool to predict an average temperature decrease of at least 1.0 ◦ C from solar cycle 23 to 24 for the stations and areas analyzed. We find for the Norwegian local stations investigated that 25–56% of the temperature increase the last 150 years may be attributed to the Sun. For 3 North Atlantic stations we get 63–72% solar contribution. [emphasis mine]
You can download a copy of the paper here [pdf].
Their paper finds that if a particular sunspot cycle is longer with less activity, the climate will show significant cooling during the next cycle.
The paper makes several important points:
- The researchers do not explain why this link exists, only that it does. This is consistent with much solar research for the past hundred years: There is a close correlation between solar activity and climate change, but the mechanism for driving it remains unclear. The Sun’s actual brightness does not change enough to account for the temperature changes.
- The researchers also note that though solar activity does not seem to account for all the temperature changes observed in the past 150 years, their data suggests its contribution is far higher that previously believed. As they note, “For the average temperatures of Norway and the 60 European stations, the solar contribution to the temperature variations in the period investigated is of the order 40%. An even higher contribution (63-72%) is found for stations at Faroe Islands, Iceland and Svalbard. This is higher than the 7% attributed to the Sun for the global temperature rise in [the 2007 IPCC report].”
- Based on their research, they predict that there will be an overall temperature drop in the Northern Hemisphere of about 1.8 degrees Fahrenheit over the next decade, with much greater temperature drops for certain local regions.
Before the global warming skeptics in my readership start crowing, I must emphasis that these researchers also note that the Sun does not appear to be sole cause of the warming seen in the past 150 years. Other factors, including the increase in carbon dioxide in the atmosphere, must be considered. The problem, however, is determining the contribution of each factor, and scientists just don’t have enough information yet to pin those numbers down.
While this research once again demonstrates that we do not yet understand completely what is going on with the Earth’s climate, it also suggests, to me at least, that if carbon dioxide is warming the atmosphere, that might actually be a very good thing, as it will likely mitigate the threatened cooling from less solar activity, which in the past has done far more harm. As the researchers point out,
de Jager & Duhau (2011) concludes that the solar activity is presently going through a brief transition period (2000-2014), which will be followed by a Grand Minimum of the Maunder type, most probably starting in the twenties of the present century. Another prediction, based on reduced solar irradiance due to reduced solar radius, is a series of lower solar activity cycles leading to a Maunder like minimum starting around 2040 (Abdussamatov, 2007).
If we are about to experience another Grand Minimum, then a little bit of warming from carbon dioxide might help to prevent crop failures and famine, as happened in the 1600s, the last time the Sun decided to shut down its sunspot factory for decades.