NASA declared Wednesday that 2018 was the fourth-hottest year in 139 years of records as average global temperatures rose alongside surging fossil fuel emissions.
The annual analysis released by NASA and the National Oceanic and Atmospheric Administration found average temperatures across land and sea surfaces 1.42 degrees Fahrenheit above the 20th-century average, putting 2018 fourth, behind 2016, 2015 and 2017.
Last December was the second-warmest December in the 139 years that records have been kept.
“The last five years are the five warmest years on record,” said Deke Arndt, the chief of climate monitoring at NOAA’s National Centers for Environmental Information in Asheville, North Carolina. “The last four years are clearly the four warmest years on record.”
He said the warming trend “very much resembles riding up an escalator over time” and compared the year-to-year differences to “jumping up and down while you’re on that escalator.”
Evidence of that warming can be seen around the world as a record-breaking heat wave roasts Australia and warming oceans in the Arctic loose frigid polar winds on huge swaths of North America. A loss of sea ice in the Arctic may be the most dramatic sign of the temperature rise. In December, NOAA’s annual report on the Arctic found that the region had its second-lowest overall sea-ice coverage on record. That loss is most pronounced in the summer, but Gavin Schmidt, the director of NASA’s Goddard Institute for Space Studies, warned Wednesday that there are “decreases in the winter as well.”
“We obviously are very concerned about what’s going on in the Arctic,” he said.
This story is developing. Check back for updates.