Earth just had its 2nd-warmest October, and 2017 could be the 2nd-warmest year on record
President Donald Trump may not acknowledge this, but October was the second-warmest such month on record, worldwide, according to new data released by NASA.
There is now about a 94 percent likelihood that 2017 will rank as the second-warmest year, globally since at least 1880, when record-keeping began, according to Gavin Schmidt, who directs NASA's Goddard Institute for Space Studies in New York.
With a temperature anomaly of 1.62 degrees Fahrenheit, or 0.90 degrees Celsius, the month barely exceeded the temperature departure from average recorded in 2016. In NASA's temperature database, the warmest October on record took place in 2015, when global average temperatures were 1.9 degrees Fahrenheit above average. At that time, though, an intense El Niño event was emerging in the Pacific Ocean.
Separately, the National Oceanic and Atmospheric Administration (NOAA) ranked October as the planet's fourth-warmest such month on record. It's likely that 2017 will be the warmest non-El Niño year on record. As human emissions of greenhouse gases continue, all years -- whether they feature El Niño conditions, La Niña, or neither -- have been growing warmer.
Each of the past three years set milestones as the warmest year, with 2016 as the current leader.
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According to a recent federal climate science report that relied in part on NASA data, global annually averaged surface air temperatures have increased by about 1 degree Celsius, or 1.8 degrees Fahrenheit, during the past 115 years.
"This period is now the warmest in the history of modern civilization," the report states.
Virtually every region on the planet was milder than average last month, the space agency found, with the exceptions of the Pacific Northwest and northeast Asia.
According to the World Meteorological Organization (WMO), 2017 is set to be the warmest year on record without an El Niño influence. El Niño events, which feature unusually mild ocean temperatures across the equatorial tropical Pacific Ocean, tend to elevate global average surface temperatures, as compared to years when they are not present.
NASA is one of several agencies around the world that keep tabs on the global thermostat. Other agencies, including the National Oceanic and Atmospheric Administration (NOAA), may rank the year slightly differently.
The Japan Meteorological Agency (JMA) found that October 2017 ranked as the third-warmest such month in its database, and the Copernicus Climate Change Service in Europe found it was the second-warmest. And according to NOAA, January through October 2017 has so far been the third-warmest such period since 1880.
Nine of the ten warmest January through October global land and ocean temperatures have taken place since 2005, NOAA said in a press release.
The bottom line is that the specific ranking -- first or second or third -- does not matter all that much in the end.
What climate scientists look at is the long-term trend over many decades. And that picture is disturbingly clear: Carbon dioxide levels are higher now than any time since about 3 to 5 million years ago, and the planet is responding by warming rapidly.
This story has been updated to include NOAA's October 2017 temperature data.
Andrew Freedman is Mashable's Senior Editor for Science and Special Projects. Prior to working at Mashable, Freedman was a Senior Science writer for Climate Central. He has also worked as a reporter for Congressional Quarterly and Greenwire/E&E Daily. His writing has also appeared in the Washington Post, online at The Weather Channel, and washingtonpost.com, where he wrote a weekly climate science column for the "Capital Weather Gang" blog. He has provided commentary on climate science and policy for Sky News, CBC Radio, NPR, Al Jazeera, Sirius XM Radio, PBS NewsHour, and other national and international outlets. He holds a Masters in Climate and Society from Columbia University, and a Masters in Law and Diplomacy from The Fletcher School at Tufts University.
