2015 Was Hottest Year on Record— by a Longshot

Last year was not just the hottest year since reporting started in 1880—it was the hottest year by a long shot, based on NASA and NOAA data released Wednesday. The average global temperature in 2015 "shattered the previous mark set in 2014 by 0.23 degrees Fahrenheit," NASA says, per the Huffington Post. "Only once before, in 1998, has the new record been greater than the old record by this much." It's worth noting that 2014 already had an average global temperature 1.24 degrees higher than the 20th century average.

The Berkeley Earth Study, released last week, also noted that 2015 was "unambiguously the hottest year on record," and the New York Times reports that Japan's meteorological agency is set to make the same announcement. The UK's Met Office confirmed the record with its own findings Wednesday as well, the Guardian reports. Fifteen of the 16 hottest years on record have taken place since 2001. "Climate change is the challenge of our generation," says NASA administrator Charles Bolden. "Today’s announcement is a key data point that should make policymakers stand up and take notice—now is the time to act." (More NASA stories.)