Even though the U.S. only had its second-hottest year on record, NASA and NOAA reported today that worldwide temperatures were the hottest since records began in 1880:
Globally-averaged temperatures in 2015 shattered the previous mark set in 2014 by 0.23 degrees Fahrenheit (0.13 Celsius). Only once before, in 1998, has the new record been greater than the old record by this much.
The planet’s average surface temperature has risen about 1.8 degrees Fahrenheit (1.0 degree Celsius) since the late-19th century, a change largely driven by increased carbon dioxide and other human-made emissions into the atmosphere.
Most of the warming occurred in the past 35 years, with 15 of the 16 warmest years on record occurring since 2001. Last year was the first time the global average temperatures were 1 degree Celsius or more above the 1880-1899 average.
The Times analysis:
Politicians attempting to claim that greenhouse gases are not a problem seized on that slow period to argue that “global warming stopped in 1998” and similar statements, with these claims reappearing recently on the Republican presidential campaign trail.
Statistical analysis suggested all along that the claims were false, and the slowdown was, at most, a minor blip in an inexorable trend, perhaps caused by a temporary increase in the absorption of heat by the Pacific Ocean.
“Is there any evidence for a pause in the long-term global warming rate?” said Gavin A. Schmidt, head of NASA’s climate-science unit, the Goddard Institute for Space Studies, in Manhattan. “The answer is no. That was true before last year, but it’s much more obvious now.”
How was the U.S. not hottest-ever last year? If you look at NASA's map, you can see why. Almost the entire world was significantly hotter than normal, except for the Antarctic Circle, bits of the North Atlantic, and the eastern U.S.:
They've even got a nifty video showing the progression over time: