2015 was by far the warmest year on record, the U.S. National Oceanic and Atmospheric Administration and NASA reported last week, with a strong El Niño weather pattern in the latter part of the year adding to a warming trend that had already begun months earlier.
“A lot of times,” said Thomas Karl, director of NOAA’s National Centers for Environmental Information, “when you break a record, you break it by a few hundredths of a degree.” But “this record, we literally smashed. It was over a quarter of a degree Fahrenheit, and that’s a lot for the global temperature.”
“2015 was by far the record year in all of the temperature datasets that are based on the instrumental and surface data,” agreed Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies. “It really underlines the fact that the planet really is still warming, there is no change in the long-term global warming rate, and we know why that is.”
The officials stressed that not all the warming could be attributed to El Niño. “The interesting thing is that 2015 did not start with an El Niño,” Schmidt said, yet “it was warm right from the beginning.”
Mooney and Warrick point to the dramatic weather events that marked 2015, including the most intense hurricane ever recorded by the U.S. National Hurricane Center. It was also a year in which climate scientists tracked increased instability in the Greenland ice sheet, and realized the oceans were absorbing far more heat than previously understood.
2015 “is breaking the record because we also have this unusually strong El Niño, but at the same time we know the ocean is now absorbing two times more heat than around the last time we had a big El Niño, which is quite a while ago,” said Texas Tech climate scientist Katharine Hayhoe.