The world’s oceans absorbed more heat in 2025 than at any time in recorded history. New research shows that the upper 2,000 meters of the ocean took in an estimated 23 zetta joules of energy more than in 2024. This level of heat gain is about 37 times the amount of energy the entire world used in 2023.
According to scientists from the U.S. National Oceanic and Atmospheric Administration (NOAA), the Chinese Academy of Sciences, and the Copernicus Marine Service, this heat absorption broke the previous records and set a new benchmark for ocean warming.
Moreover, average sea surface temperatures in 2025 were about 0.5°C (0.9°F) above the long-term average measured between 1981 and 2010. This marked one of the highest surface temperature years on record.
The oceans act as the planet’s biggest heat reservoir. They absorb about 90% of excess heat caused by greenhouse gas increases in the atmosphere. Therefore, ocean temperature trends are one of the most reliable indicators of global warming
However, hotter oceans are not just a climate statistic. They drive sea-level rise, disrupt marine ecosystems, and make extreme weather events more severe. Warm water feeds stronger storms and creates conditions that stress coral reefs and fisheries.
Scientists also point out that the rate of ocean warming has accelerated drastically over recent decades. Studies show that present warming rates are more than four times faster than they were in the late 1980s.
Despite natural climate cycles like El Niño and La Niña influencing surface temperatures, the long-term trend of increased ocean heat is driven primarily by human-caused greenhouse gas emissions.
Scientists warn that without rapid and sustained action to cut emissions, ocean temperatures will continue rising, intensifying climate risks for coastal communities and global ecosystems.
Reference- Scientific American, Phy.org, TIME, NOAA website, National Geographic