Small changes in solar output have a significant effect on the earth’s climate, National Research Council scientists report in a new study published by the National Academies Press. The new study indicates an increase in solar output during the past century has played a greater role in recent global warming than claimed by the United Nations Intergovernmental Panel on Climate Change.
Dozens of Scientists Participated
The National Research Council assembled a team of scientific experts encompassing many fields of solar and earth sciences.
As explained in a NASA press statement announcing the report, “Understanding the sun-climate connection requires a breadth of expertise in fields such as plasma physics, solar activity, atmospheric chemistry and fluid dynamics, energetic particle physics, and even terrestrial history. No single researcher has the full range of knowledge required to solve the problem. To make progress, the NRC had to assemble dozens of experts from many fields at a single workshop. The report summarizes their combined efforts to frame the problem in a truly multi-disciplinary context.”
Small Changes, Large Impacts
The scientists discovered even small variations in the sun’s radiance can have substantial impact on terrestrial climate and temperatures.
“Of particular importance is the sun's extreme ultraviolet (EUV) radiation, which peaks during the years around solar maximum,” the NASA press statement explained. “Within the relatively narrow band of EUV wavelengths, the sun’s output varies not by a minuscule 0.1%, but by whopping factors of 10 or more. This can strongly affect the chemistry and thermal structure of the upper atmosphere.”
Changes in solar output impact regional climate regimes as well as global temperatures, the scientists report.
“The solar cycle signals are so strong in the Pacific,” the NASA press statement reports, “that [National Center for Atmospheric Research scientist Gerald] Meehl and colleagues have begun to wonder if something in the Pacific climate system is acting to amplify them. ‘One of the mysteries regarding Earth's climate system ... is how the relatively small fluctuations of the 11-year solar cycle can produce the magnitude of the observed climate signals in the tropical Pacific.’”
James M. Taylor (email@example.com ) is managing editor of Environment & Climate News.
“The Effects of Solar Variability on Earth’s Climate,” National Academies Press: http://www.nap.edu/catalog.php?record_id=13519 
“Solar Variability and Terrestrial Climate,” NASA Science News: http://science.nasa.gov/science-news/science-at-nasa/2013/08jan_sunclimate/