Last year was the world’s warmest year ever recorded, beating out 2014 in average temperatures over land and ocean surfaces, according to both NASA and the National Oceanic and Atmospheric Administration.
Federal scientists announced the news this morning, marking the second year in a row that broke temperature records stretching back to 1880. It was widely expected and in line with NOAA’s announcement earlier this month that 2015 was the second-warmest year for the United States (Greenwire, Jan. 7).
A strong El Niño pushed temperatures particularly high at the tail end of the year, contributing to an unprecedentedly warm December. But on a call with reporters today, NOAA and NASA scientists emphasized that 2015 would have broken records even without the “El Niño assist.”
“Even without El Niño, this would have been the warmest year on record. We’re really looking at a long-term trend,” said Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies. “This is really just a symptom of this long-term trend.”
The year was significantly warmer than 2014, the previous record holder, with the average temperature across global land and ocean surfaces 1.63 degrees Fahrenheit above the 20th-century average. In 2014, that number was 1.24 F.
December broke its own records, reaching 2 F above the 20th-century average. That’s the first time in 137 years any month has departed so far from the average.
The bottom line: Both NOAA and NASA are “virtually certain” that the world experienced its hottest year in 2015.
Schmidt and Tom Karl, director of NOAA’s National Centers for Environmental Information, also predicted that 2016 would be even hotter.
“I think probably both Gavin and I would say the odds favor 2016,” Karl said. “If you were going to be betting, you would bet that it would be warmer than 2015.”
2015 also marked the first time the temperature was 1 degree Celsius above the 19th-century average (based on measurements from 1880 to 1900). That is a significant milestone at a time when world leaders aim to limit global temperatures to 2 C above preindustrial levels, as outlined in the recent Paris accord.
Since 1970, the world has warmed by about 0.15 C a decade, according to both NOAA and NASA data. The world is already seeing the impacts of global warming, and those impacts are just going to get clearer, Schmidt said.
“There has to be a sustained discourse and monitoring of the situation from everybody for this problem to get under control,” Schmidt said. “It’s really something that depends on the long-term trends and our long-term ability to maintain focus on this issue.”
