The world’s oceans absorbed more heat in 2025 than in any other year since modern record-keeping began, according to a new international study released on Friday.
Published in the journal Advances in Atmospheric Sciences, the study found that ocean heat content rose sharply last year, increasing by about 23 zettajoules of energy — an amount equivalent to roughly 37 years of global energy consumption at 2023 levels, Xinhua news agency reported.
The research was conducted by more than 50 scientists from 31 institutions worldwide. By combining data from major international centres and independent research groups across Asia, Europe and the Americas, the team concluded that heat stored in the upper 2,000 metres of the ocean reached its highest level on record in 2025, confirming a sustained warming trend.
Researchers, including scientists from the Institute of Atmospheric Physics, noted that ocean warming varied across regions. About 16 per cent of the global ocean surface recorded its warmest year ever in 2025, while another 33 per cent ranked among the three warmest years in historical records. The most rapid warming was observed in the tropical and South Atlantic, the North Pacific and the Southern Ocean.
While heat stored in the deep ocean set a new record, surface temperatures followed a slightly different pattern. The global average sea-surface temperature in 2025 was the third highest on record, remaining around 0.5 degrees Celsius above the recent baseline and marginally lower than the peaks seen in 2023 and 2024.
Despite this, elevated surface temperatures continued to influence weather patterns by increasing evaporation and rainfall. Researchers said these conditions contributed to extreme weather events in 2025, including severe flooding in Southeast Asia and Mexico, as well as drought conditions in parts of the Middle East.
The study warned that ongoing ocean warming has wide-ranging consequences. It contributes to sea-level rise through thermal expansion, intensifies marine heatwaves, and adds heat and moisture to the atmosphere, increasing the likelihood of stronger storms and other extreme weather events.
Scientists stressed that as long as the Earth continues to accumulate excess heat, new ocean heat records are likely to be set in the coming years.
— IANS
