An unparalleled heat wave in Eastern Europe, coupled with intense droughts and fires in Russia, put Earth’s temperatures in the headlines this summer. Likewise, an exceptionally warm July in the eastern United States strained power grids, forced nursing home evacuations, and slowed transit systems.
But from a global perspective, how warm was it? And was global warming the cause of the unusual heat waves? Scientists at NASA’s Goddard Institute for Space Studies (GISS), led by James Hansen, released an analysis that addressed these questions.
The global maps above show temperature anomalies; that is, how temperatures in June through August 2010 (top image) and 2009 (bottom) differed from the mean temperatures from 1951-1980. Shades of red represent warmer than normal temperatures, with blues depicting cooler.
Globally, 2010 was the 4th warmest summer in GISS’s 131-year-temperature record. The summer of 2009 was the 2nd warmest. The slightly cooler 2010 temperatures were primarily the result of a moderate La Niña replacing a moderate El Niño in the Pacific Ocean. Note in 2010 that much of the eastern Pacific, the west coasts of North and South America, and much of Antarctica were cooler than the long-term mean. Temperatures were extremely warm in western Russia and the Antarctic Peninsula.
The unusually warm summer temperatures in the U.S. and Eurasia created the impression of global warming run amuck; last winter’s unusually cool temperatures created the opposite impression. But extrapolating global trends based on one or two regions can be misleading…