The World Just Experienced the Four Hottest Years on Record

NASA and NOAA are both shut down, so outside scientists affirmed the milestone this week.

May McKeown, an Australian farmer, drives her truck to feed the remaining cattle on her drought-affected property in July. (David Gray / Reuters)

2018 was hotter than any year in the 19th century. It was hotter than any year in the 20th century. It was hotter than any year in the first decade of this century. In fact, with only three exceptions, it was the hottest year on Earth since 1850.

Those three exceptions: 2018 was slightly cooler than 2015, 2016, and 2017. The past four years, in other words, have been the four hottest years ever reliably measured.

That’s according to Berkeley Earth, a nonprofit research group that published its annual temperature analysis on Thursday. The new finding “remains consistent with a long-term trend toward global warming,” the report says.

Berkeley Earth is a respected scientific organization, but it’s unusual that this news should come from it alone. Normally, Americans hear about these milestones from their own government. NASA and the National Oceanic and Atmospheric Administration were both due to publish their version of this analysis last week, on January 17. The United Kingdom’s Met Office and Berkeley Earth also planned to release their own findings that day.

But it was not to be. The ongoing federal shutdown has indefinitely delayed the NASA and NOAA reports, so Berkeley Earth decided to go ahead with its report. “We actually finished our analysis last week, but held off releasing it in the hope that things would be resolved,” said Zeke Hausfather, an analyst for the group, in an email. “But at this point it is clear that nothing will happen soon.”

The report’s overall findings will not surprise most scientists. The European Union’s climate center has already concluded that 2018 was the fourth-warmest year on record.

But the report contains plenty of records worth noting in their own right. 2018 was the hottest year ever recorded in Antarctica, a finding with worrisome implications for sea-level rise. Twenty-nine countries—including France, Germany, Italy, Greece, and the United Arab Emirates, where temperatures hit 123 degrees Fahrenheit in June—experienced their warmest year ever last year, too.

The report also underscores that climate change has already begun—and that we are running out of time to keep it under control. It finds that Earth was about 1.16 degrees Celsius warmer in 2018 than it was during the late-19th century. Last year, the Intergovernmental Panel on Climate Change (IPCC) warned that if global warming exceeds 1.5 degrees Celsius—just 0.4 degrees Celsius above where we are now—then widespread environmental upheaval could result. Perhaps as soon as 2040, climate change could leave hundreds of millions of people with scarce food and water.

To avoid that world, the IPCC said, “rapid and far-reaching” energy changes were needed. So far, nothing resembling those changes has occurred—though admittedly only a few months have elapsed. Meanwhile, carbon dioxide pours into the atmosphere at record rates. And given that a warm El Niño might develop in a few months, Berkeley Earth predicts that 2019 will “very likely be warmer than 2018.”

There’s a coin toss’s chance, it says, that we’re living in the second-warmest year ever measured right now.