Nearly tied with 2016 for the hottest year on record, 2020 was hot, hot, hot! NPR climate reporters Rebecca Hersher and Lauren Sommer explain why more heat trapped in the atmosphere means longer heat waves, less ice in the Arctic, bigger wildfires, and more powerful hurricanes. For more reporting on the hottest decade, check out this story. You can follow Rebecca on twitter @rhersher and Lauren @lesommer. And, as always, email us at shortwave@npr.org.