According to a study by the British University of Reading published in the journal Environmental Research Letters, ocean surface warming has quadrupled in the last four decades. In the late 1980s, ocean temperatures were rising at a rate of 0.06 degrees Celsius per decade, while currently, it is increasing at 0.27 degrees every ten years. This increase explains the unprecedented high ocean temperatures recorded in 2023 and early 2024.
In the words of Chris Merchant, ocean and climate change researcher at the University of Reading, "if the oceans were a bathtub of water, we could say that in the 1980s, the hot tap was opening slowly, warming the water by only a fraction of a degree each decade. Now the tap is opening much faster, and the warming is accelerating." Experts indicate that the only way to curb this warming is by reducing global carbon dioxide emissions and moving towards net zero emissions.
The accelerated rise in ocean temperatures is due to the growing energy imbalance of the Earth, which absorbs more energy from the Sun than it emits into space. This imbalance has doubled since 2010, primarily due to the increase in greenhouse gases in the atmosphere and the reduced reflection of sunlight by the planet. Global ocean temperatures reached historic highs for 450 consecutive days in 2023 and early 2024.
Scientists compared this phenomenon to the El Niño period in the Pacific in 2015-2016 and found that the record heat during the 2023-2024 period is due to the faster warming of the sea surface in the last decade. They warn about the possibility that the increase in ocean temperature over the last 40 years could be surpassed in just 20 years, indicating the urgency to reduce fossil fuel burning to prevent even faster temperature increases in the future and to stabilize the climate.