It’s Official: 2015 Was the Hottest Year in Over a Century

A strong El Niño helped global temperatures reach new highs

Icebergs melting
Icebergs melting in Disko Bay, Greenland Paul Souders/Corbis

As a snowstorm of alarming proportions barrels down on East Coast cities, people may be thinking longingly of warmer months. But this week, despite the threat of such a frigid storm, separate analysis from  the National Oceanic and Atmospheric Administration (NOAA), NASA, and the U.K.'s Met Office report that 2015 was the planet's warmest year since modern record-keeping began in 1880.

According to these reports, 2015 wasn't just the warmest year, it was the warmest by a surprising margin, fueled in part by a very strong El Niño. The globally averaged temperature in 2015 beat out the previous record-holding year, 2014, by a whopping 0.23 degrees Fahrenheit, a press release from NASA reports.

This record is the fourth time it has been set since 2000, reports Brian Clark Howard for National Geographic. And continues the now 39-year-long streak of above-average temperatures. ​

A closer look at the year shows even more record-breaking temperatures. Every month except January and April produced record global average temperatures, reports Christie Aschwanden for FiveThirtyEight. Although the current El Niño pattern seemed to start in 2014, it faltered before picking up as expected in 2015.

Earth's Long-Term Warming Trend, 1880-2015

That delay means that 2016's temperatures may also get a boost from El Niño and continue to be very warm, "perhaps even another record," says Gavin Schmidt, head of NASA's Goddard Institute for Space Studies, Aschwanden reports. Already the U.K. Met Office expects 2016 to even beat out the past scorcher of a year or at least be as warm as 2015.​

However, the odd start for the current El Niño makes that prediction a little tricky. Kevin Trenberth, a senior scientist at the National Center for Atmospheric Research in Boulder, Colorado, thinks that the warming that follows an El Niño may have already occurred, reports Tom Randell and Blacki Migliozzi for "If I had to guess, 2015 will probably beat out 2016," he says.

Since weather patterns can influence regional temperatures, the contiguous U.S. only experienced the second hottest year on record, reports Bill Chappell for NPRBut the global trend is the one to watch. "This record year really is just emphasizing the fact that there is a very, very strong long-term trend in temperature that we have associated very strongly with the human emissions of greenhouse gases," Schmidt tells NPR.

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