Since 1998, human activity has trapped more than two billion atomic bombs’ worth of extra heat in our planet’s climatic system—primarily by raising greenhouse-gas concentrations to their highest levels in 800,000 years, at the fastest rate Earth has seen since the age of dinosaurs.

That extra heat can’t accrue without consequence. Two new reports confirm that 2016 was the hottest year on record—and demonstrate that human activity made the freakish heat far likelier than it otherwise would have been.

On August 10, the U.S. National Oceanic and Atmospheric Administration (NOAA) released its annual State of the Climate report, published in concert with the American Meteorological Society. The 298-page report, prepared by a team of scientists led by NOAA’s National