The world’s oceans were the warmest on record for the fourth year in row in 2022.

A study by an international team of scientists from sixteen institutes worldwide found that the five hottest years for oceans all happened in the past six years and that the speed at which oceans are warming is getting increasingly fast.

Published in the journal Advances in Atmospheric Sciences, the study looked at temperatures from the ocean surface to 2,000 meters (6,560 feet) deep, examining data going back to the 1950s.

“The state of our oceans can measure the world’s health, and judging by the updated oceanic observations … we need a doctor,” the team of authors said in an accompanying press release.

The real impact of climate change

Oceans serve as a good indicator of the real impact of climate change because compared to air temperatures, they are less affected by seasonal changes and day-to-day weather cycles. Covering almost three quarters of Earth’s surface, oceans absorb the vast majority of the world’s heat.

Since 1970, more than 90% of the planet’s excess heat went into the oceans, the study said.

The scientists said that the global long-term warming trend is now so steady and robust that annual records continue to be set every year.

What the data says

Two separate data sets evaluated in the paper — one from the Chinese Academy of Sciences (CAS) and another from the U.S. National Oceanic and Atmospheric Administration (NOAA) — showed relatively similar increases in temperatures in the last year.

Ocean temperatures, which are measured in zettajoules (ZJ), have typically increased by about 5.3 ZJ or 5.5 ZJ a year over the last six decades, according to NOAA and CAS, respectively. However, between 2021 and 2022, ocean temperatures increased by about 9.1 ZJ or 10.9 ZJ, according to the two data sets.

Why ocean warming matters

Sea surface temperatures are a major influence on the world’s weather. Hotter oceans help supercharge extreme weather, leading to more intense hurricanes and typhoons and more moisture in the air, which brings more intense rains and flooding. Warmer water also expands, pushing up sea levels and endangering coastal cities. (Photo: James Peacock)

Rising temperatures also mean ocean waters have less oxygen, which affects marine life, hurting fishing communities and their economies.

Resources:

Articles which the above is based on can be found in The Hill, the Guardian, PhysOrg and CNN.

The press release is here.

The full peer-reviewed journal paper can be read here.