World's ocean heat grows to record high: study

The world continued to see ocean heat reaching new records, as the year 2022 was the warmest in recorded human history, according to a recent study.

Conducted by a team of 24 scientists from 16 institutes mainly in China, the United States, and Italy, the study was published in the international journal Advances in Atmospheric Sciences.

Compared with 2021, the previous hottest year ever recorded, the upper 2,000 meters of the Earth's oceans have absorbed a larger amount of heat that's "enough to boil 700 million kettles, each containing 1.5 liters of water," said Cheng Lijing, an author of the study and researcher at the Institute of Atmospheric Physics under the Chinese Academy of Sciences.

Ocean warming is a key indicator for quantifying climate change since more than 90 percent of global heat ends up in the oceans. The scientist believes that the increase in heat within the oceans is further proof of global warming.

Records for ocean warming have been broken almost yearly since 2017. Due to the ocean's delayed response to global warming, the trend of ocean temperatures will persist for decades, Cheng noted.

Besides temperatures, the study also calculated the salinity of ocean water, and it found that areas of high salinity had an increase in salinity, whereas the opposite was true for areas of lower salinity.

"The salty gets saltier, while the fresh gets fresher" pattern also reached its highest level on record in 2022, said the study.

Warmer oceans lead to sea level rises and more extreme weather, in the form of strong storms and hurricanes. They also become less efficient at absorbing carbon, causing more human-emitted carbon dioxide to remain in the atmosphere, exacerbating global warming.

Better awareness and understanding of the changes in ocean heat and salinity are a basis for the actions to combat climate change, Cheng added, explaining the significance of the study.

Scientists also shared ocean data recorded last year by the Chinese institute and the U.S. National Oceanic and Atmospheric Administration in the study.