A new study has revealed that the world’s oceans are heating up more than four times faster than in the 1980s, driven by rising greenhouse gas emissions and a growing energy imbalance in the Earth’s climate system.
The research, published on 28 January 2025 in Environmental Research Letters, found that ocean temperatures, which were increasing at a rate of 0.06°C per decade in the late 1980s, are now warming at 0.27°C per decade. Scientists warn that this trend could accelerate further in the coming years, leading to more extreme weather events and disruptions to marine ecosystems.
According to the study, Earth’s energy imbalance —where more heat is being absorbed than is radiated back into space—has nearly doubled since 2010. This imbalance is primarily caused by increasing greenhouse gas concentrations and a decline in the planet’s ability to reflect solar radiation.
Lead author Professor Chris Merchant from the University of Reading compared the phenomenon to a filling bathtub. “In the 1980s, the hot tap was running slowly, increasing ocean temperatures gradually. Now, it is running much faster, accelerating warming at an alarming rate. The only way to slow this down is by cutting carbon emissions and moving towards net zero,” he said.
The findings come after global ocean temperatures remained at record highs for 450 consecutive days in 2023 and early 2024. While part of this warming was influenced by El Niño, a natural climate pattern, researchers found that 44% of the record-breaking heat was due to the accelerating rate of ocean warming over the past decade.
A comparison with the 2015-16 El Niño event suggests that background warming has intensified significantly, pushing ocean temperatures to unprecedented levels.
Scientists caution that the current pace of ocean warming could increase further in the coming decades. The study warns that the rise in ocean temperatures seen over the past 40 years could be matched or even exceeded within the next 20 years, significantly impacting global climate patterns.
Given that oceans regulate global temperatures and influence weather systems, experts stress that reducing fossil fuel emissions is critical to slowing down further warming. Without immediate action, the consequences of rising ocean temperatures—such as stronger storms, rising sea levels, and ecosystem disruptions—are expected to intensify.
The study adds to a growing body of research highlighting the urgent need for climate mitigation measures to stabilise global temperatures and reduce the long-term impacts of ocean heating.
