The year was one in a string that have been a full degree Celsius, or 1.8 degrees Fahrenheit, warmer than temperatures in the late 19th century, the report found.
The year 2018 is likely to have been the fourth warmest year on record, a scientific group pronounced Thursday — and joins three other extra-hot years since 2015 that suggest a leap upward in warmth that the Earth may never return from in our lifetimes.
The warmest year on record for the Earth’s land and oceans was 2016 — by a long shot, thanks to a very strong El Nino event. That’s followed by 2017, 2015, and now 2018, said Zeke Hausfather, a research scientist with Berkeley Earth, which released the findings.
“2018 is consistent with the long term warming trend,” Hausfather said. “It’s significantly warmer than any of the years before 2015. There’s still this big bump up after 2014, and 2015, 2016, 2017, and 2018 are all in a class of their own.”
While expert groups have sometimes divided on such annual temperature rankings — and not all assessments are yet in — Berkeley Earth’s findings appear unlikely to be disputed.
The Copernicus Climate Change Service, a European Union body, has also proclaimed 2018 the fourth warmest year on record earlier this month.
And Kevin Cowtan, a researcher at the University of York who also keeps an influential temperature dataset, agreed with the ranking, though he noted by email that he is only able to track data through November of last year due to the U.S. government shutdown, leaving his assessment one month short at present.
“Our results to November clearly put 2018 in 4th place, significantly warmer than 2010 in 5th,” said Cowtan. “The 11 hottest years on record have all occurred since 2005.”
Amid the government shutdown the U.S.’s two top keepers of temperature records — NASA and NOAA — have not yet released their findings. Last year, both agencies released their assessments for 2017′s temperatures, which NASA called the second warmest and NOAA the third, on January 18.
Hausfather said a coordinated release had been planned for January 17 with his organization and the U.S. government agencies — before the shutdown, that is. Once that happened, he said, Berkeley Earth decided to go ahead and release its own numbers.
In response to a request for comment, NOAA said that it would look into the state of the 2018 temperature release. Meanwhile, on Thursday NASA’s Gavin Schmidt, who heads the agency office that keeps the temperature record, tweeted that their release has been “indefinitely postponed” due to the shutdown.