2021 was the world’s sixth-warmest year on record, according to the U.S. National Oceanic and Atmospheric Administration. This was an improvement over 2019 and 2020, which ranked among the top three warmest on record, but it wasn’t cause for celebration. The ocean heat content – a measure of the amount of heat stored in the upper levels of oceans – broke another record high in 2021, surpassing the previous record high set in 2020.
