Oceans set heat record in 2025 for ninth straight year
Earth's oceans absorbed a record-breaking amount of heat in 2025, marking the ninth consecutive year of unprecedented warming and intensifying concerns about extreme weather, rising seas, and collapsing marine ecosystems, according to research published Friday by an international team of scientists.
The upper 2,000 meters of the world's oceans absorbed 23 zettajoules more energy than in 2024—an amount equivalent to roughly 37 years of global energy consumption—according to the study in Advances in Atmospheric Sciences. The research involved more than 50 scientists from 31 institutions across three continents.
"Every year, we are witnessing an increase in global temperatures—setting new records has become a recurring theme," said Prof. John Abraham from the University of St. Thomas, who co-authored the study. "Global warming equates to ocean warming. To understand how much the Earth has warmed or how quickly we may warm in the future, we must look to the oceans
"Ocean warming continues to have significant repercussions on the Earth's systems," the researchers stated. The North Atlantic and Mediterranean Sea are experiencing warming alongside increased salinity, acidity, and decreased oxygen levels, leading to profound shifts in marine conditions that make ecosystems increasingly vulnerable.
"As long as the Earth's heat continues to rise, ocean heat content will keep increasing, and records will keep being broken," Abraham said. "The greatest uncertainty in climate change lies in human choices. Together, we can lower emissions and work towards a future where humans can prosper in a stable climate".
The findings underscore the urgent need to reduce greenhouse gas emissions to slow ocean warming and prevent further climate disruption.
The upper 2,000 meters of the world's oceans absorbed 23 zettajoules more energy than in 2024—an amount equivalent to roughly 37 years of global energy consumption—according to the study in Advances in Atmospheric Sciences. The research involved more than 50 scientists from 31 institutions across three continents.
"Every year, we are witnessing an increase in global temperatures—setting new records has become a recurring theme," said Prof. John Abraham from the University of St. Thomas, who co-authored the study. "Global warming equates to ocean warming. To understand how much the Earth has warmed or how quickly we may warm in the future, we must look to the oceans
"Ocean warming continues to have significant repercussions on the Earth's systems," the researchers stated. The North Atlantic and Mediterranean Sea are experiencing warming alongside increased salinity, acidity, and decreased oxygen levels, leading to profound shifts in marine conditions that make ecosystems increasingly vulnerable.
"As long as the Earth's heat continues to rise, ocean heat content will keep increasing, and records will keep being broken," Abraham said. "The greatest uncertainty in climate change lies in human choices. Together, we can lower emissions and work towards a future where humans can prosper in a stable climate".
The findings underscore the urgent need to reduce greenhouse gas emissions to slow ocean warming and prevent further climate disruption.
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