According to new reports published Wednesday, the last five years—from 2014 to 2018—are the warmest years ever recorded in the 139 years that the National Oceanic and Atmospheric Administration (NOAA) has tracked global heat. And 2018 was the fourth hottest year ever recorded.

Global air temperatures have warmed steadily over past decades, shifting up and down slightly from year to year depending on natural climate oscillations like El Niño, but following a consistent upward path. Land temperatures, they said, were more than two degrees Fahrenheit warmer than the 20^th century average.

“It’s a long-term trip up the elevator of warming,” says Deke Arndt, the chief of the global monitoring branch of NOAA’s National Centers for Environmental Information in