Climate Change: What's Going On With the Sun?

Throughout the past century, while greenhouse gas (GHG) abundances have been steadily increasing and influencing Earth’s climate, the Sun has remained relatively bright and quiescent. Solar cycles have been steadily active, with instantaneous sunspot numbers at solar maximum exceeding 100 in every cycle since 1893 (Cycle 13). The climate warming we have experienced since the beginning of the modern industrial era cannot be attributed to the Sun. However, the recent minimum between Cycles 23 and 24, and NASA predictions of a substantially lower sunspot number at the 2013 solar maximum, suggest that the Sun’s recent bright and quiescent period may be ending.

Dan Lubin, Scripps Institute of Oceanography and SETI Institute