Last decade was hottest on record
Scientists said they see no end in sight to the way man-made climate change keeps shattering records.
WASHINGTON — The decade that just ended was by far the hottest ever measured on Earth, capped off by the second-warmest year on record, two U.S. agencies reported Wednesday. And scientists said they see no end to the way man-made climate change keeps shattering records.
“If you think you’ve heard this story before, you haven’t seen anything yet,” Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies, said at the close of a decade plagued by raging wildfires, melting ice and extreme weather that researchers have repeatedly tied to human activity.
Schmidt said Earth as a whole is probably the hottest it has been during the Holocene — the past 11,500 years or so — meaning this could be the warmest period since the dawn of civilization.
But scientists’ estimates of ancient global temperatures, based on tree rings, ice cores and other telltale signs, are not precise enough to say that with certainty.
The 2010s averaged 58.4 degrees Fahrenheit worldwide, or 1.4 degrees higher than the 20th century average and more than onethird of a degree warmer than the previous decade, which had been the hottest on record, according to the National Oceanic and Atmospheric Administration.
The decade had eight of the 10 hottest years on record. The only other years in the Top 10 were 2005 and 1998.
NASA and NOAA also calculated that 2019 was the second-hottest year in the 140 years of recordkeeping. Five other global teams of monitoring scientists agreed, based on temperature readings taken on Earth’s surface, while various satellite-based measurements said it was anywhere from the hottest year on record to the thirdhottest.
Several scientists said the coming years will be even hotter, knocking these years out of the record books.
“This is going to be part of what we see every year until we stabilize greenhouse gases” from the burning of coal, oil and gas, Schmidt said.
“It’s sobering to think that we might be breaking global temperature records in quick succession,” said Georgia Tech climate scientist Kim Cobb. “2020 is off to a horrifying climate start, and I fear what the rest of the year will bring to our doorsteps.”
NASA’s Schmidt said that overall, Earth is nownearly 2.2 degrees hotter since the beginning of the industrial age, a number that is important because in 2015 global leaders adopted a goal of preventing 2.7 degrees of warming since the rise of big industry in the mid- to late 1800s. He said that shows the global goal can’t be achieved.
Other explanations that rely on natural causes — extra heat from the sun, more reflection of sunlight because of volcanic particles in atmosphere, and just random climate variations — “are all much too small to explain the long-term trend,” Princeton University climate scientist Michael Oppenheimer said.
Scientists said the decadelong data is more telling than the year-toyear measurements, where natural variations such as El Niño, the periodic warming of the Pacific Ocean, come into play.