A new study has shown that the rate of ocean warming has more than quadrupled over the past 40 years. The study, by researchers at the University of Reading in the UK, helps to explain why there have been unprecedented ocean temperatures in 2023 and 2024.
Global ocean temperatures hit record highs for 450 days straight in 2023 and early 2024. Some of this unusual warmth came from the El Niño that was taking place at the time, but the rest of the increased temperature came from the sea surface warming up more quickly over the past 10 years than in previous decades. In the late 1980s, ocean temperatures were rising at a rate of 0.06 degrees Celsius per decade. According to the recent research, they are now increasing at 0.27 degrees per decade.
The acceleration of ocean warming is driven by growth in the Earth’s energy imbalance, meaning that more energy from the sun is being absorbed by the Earth than is escaping back into space. This energy imbalance has roughly doubled since 2010 as a result of two factors: increasing greenhouse gas concentrations in the atmosphere and reductions in the Earth’s albedo.
Earth’s albedo, the measure of how much sunlight is reflected back into space, has been declining since the 1970s, primarily due to the decrease in snow and ice cover, especially in the Arctic.
The overall rate of ocean warming observed over recent decade is likely to only increase. This underscores the urgency of reducing fossil fuel burning to avoid even more rapid temperature increases in the future.
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Ocean-surface warming four times faster now than late-1980s
Photo, posted January 18, 2007, courtesy of Alexey Krasavin via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio
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