Taking the temperature on temperature: Why are climate scientists so sure that our planet is in fact getting warmer? adam hadhazy went looking for answers.

With an alarming frequency, the public keeps hearing that this or that year was the hottest on record. Almost true to form, NOAA and NASA in January announced that 2019 was the second- warmest year ever measured. In fact, nine out of the 10 hottest years in the era of instrument-recorded global temperatures dating back to the late 1800s occurred in the past decade. The drumbeat continues, with 2020 on its way to dethroning 2016 as the warmest yet on average across our planet’s surface.