Science weekly: New study casts doubt on solar causes for global warming

Chris Sessions

A new study (Ariana Berkemeier / The Signpost)
A new study challenges the idea that global warming is affected by sunspot activity. (Ariana Berkemeier / The Signpost)

The sun provides a great deal of earth’s energy. If you doubt this, try taking a step outside on a sunny August day, and you will be made a believer.

There have been some suggestions, however, that sunspot activity, which acts as an indicator of the sun’s “weather”–how much energy it is radiating, for example, in any given period–can be traced to global warming or cooling and that our current climate increase has been affected by sunspot activity.

This seemed to indicate that global warming is not tied strongly to human industrial activity but rather is a consequence of increased solar activity.

A recent study presented at the IAU XXIX General Assembly in Honolulu, as noted at, appears to counter this hypothesis.

The hypothesis, always controversial among researchers, was based on two sunspot counts, the Wolf and Group Sunspot Numbers, respectively, which suffered from discrepancies and seemed to show significant increase in solar activity over the last few centuries.

But the issue had more to do with the ability of older telescopes to detect sunspots than the actual number of sunspots occurring. This calibration error has been resolved, and the corrected data has been dubbed the Sunspot Number Version 2.0.

The effort has been led by Frédéric Clette, Director of the World Data Centre, Ed Cliver of the National Solar Observatory and Leif Svalgaard of Stanford University.

These new numbers indicate that solar activity has not been trending upward over the last few centuries. The SNV2.0 makes it difficult to argue that human industry is not behind the current global warming trends.