With less than a month left in the year, 2020 is neck-and-neck with 2016 for the title of hottest year in recorded history. It is virtually certain to be at least the second-hottest year.
Wherever it ultimately places in the record books, 2020’s feverish heat came without the major El Niño event that boosted global temperatures to a new high four years ago—and thus this year provides an important marker of the power of the long-term warming trend driven by human activities that emit greenhouse gases. “Until we stop doing that, we’re going to see this over and over again,” says Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies, which keeps the agency’s temperature records.
