The research reveals why ocean temperatures reached unprecedented levels in 2023 and early 2024.
According to a new study, the pace of ocean warming has increased more than four times in the last forty years.
In the late 1980s, ocean temperatures were increasing by roughly 0.06 degrees Celsius each decade, but that rate has now surged to 0.27 degrees Celsius per decade.
The findings, released today (Tuesday, January 28, 2025) in Environmental Research Letters, clarify the reasons behind the exceptional ocean temperatures experienced recently.
Professor Chris Merchant, the study’s lead author from the University of Reading, explained: “If we think of the oceans like a bathtub, in the 1980s the hot faucet was barely dripping, heating the water slowly. Now, however, the hot faucet is running strongly, accelerating the warming. To reduce this warming, we need to start turning off the hot faucet by lowering global carbon emissions and aiming for net-zero.”
Energy imbalance
The rapid warming of the oceans is linked to the increasing energy imbalance on Earth, where more energy from the Sun is being absorbed than is released back into space. Since 2010, this imbalance has approximately doubled, partly due to rising greenhouse gas levels and the Earth reflecting less sunlight back to space.
Global ocean temperatures reached record heights for 450 consecutive days in 2023 and early 2024. While some of the heat can be attributed to El Niño, a natural warming event in the Pacific, researchers discovered that the additional record heat is largely due to the faster warming of the ocean surface in the past decade compared to previous decades. 44% of this record warmth has been linked to the oceans absorbing heat at an increasing pace.
Expect more warming
The study indicates that the rate of global ocean warming observed in recent decades may not be a reliable indicator of future trends. It is possible that the increase in ocean temperatures seen over the last 40 years could be surpassed within the next 20 years. Since surface ocean temperatures significantly influence global warming, this is critical for overall climate trends. The accelerating rate of warming highlights the urgent need to reduce fossil fuel consumption to prevent even steeper temperature rises in the future and to start stabilizing the climate.
