Warmest average global ocean surface temperature

In 2022, the heat content for the upper 2,000 metres (1,240 miles) of Earth's oceans was measured up to 245.4 ZJ (zettajoules; 245.4 billion trillion Joules) above the 1981–2010 average. This amount of energy is equivalent to 100 times the global electricity generated in 2021 or enough to boil 700 million kettles every second for a year. The results were published in the journal Advances in Atmospheric Sciences on 11 January 2023.

This is the sixth year in a row that the ocean temperature has drastically exceeded the 1981–2010 average. The previous record was logged in 2021, with an upper limit of 235 zettajoules of additional heat energy measured.

Two different data sets, one produced by the Chinese Academy of Sciences and one by the USA's National Oceanic and Atmospheric Administration, produced slightly different estimates of ocean heat content but both agreed that Earth's ocean has never been hotter than in 2022, since records began in 1958.

The ever-increasing heat of the ocean is having huge impacts on the natural world, including threatening the survival of sensitive biodiversity hotspots such as coral reefs and kelp forests. It's also contributing to more extreme weather, including greater levels of rain and more violent storms, as well as increased coastal flooding as warmer water expands, raising sea levels.