Annual average temperatures of the oceans’ surfaces have been diverging from the 20th century (1900-1999) average more and more since the 1980s. In 2018, global ocean surface temperatures were 0.66 degrees Celsius higher than that century’s average, according to the National Oceanic and Atmospheric Administration (NOAA).

The Arctic is warming twice as fast as the rest of the planet, driven by melting sea ice and thawing of carbon-rich Arctic permafrost, according to the National Oceanic and Atmospheric Administration (NOAA). In 2016, average Arctic surface temperatures were 3.5 degrees Celsius warmer than they were at the start of the 20th century, says NOAA.