Over the past 150 years, global warming has heated the Earth’s oceans as if an atomic bomb explodes every second, according to a new study. More than 90% of the heat trapped by greenhouse gases emitted by humans is absorbed by the ocean, and only a few percent is heating the air, land, and glaciers. This huge amount of energy affects sea level rise and intensifies hurricanes.
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Most of the heat has been stored in the depths of the ocean, but the measurement of their temperature only began in recent decades. Existing estimates of the heat absorbed by the oceans stretch back only to about 1950. The new work extended that back to 1871. Scientists say that knowing about changes in ocean temperature in the past is important for climate forecasting.
The average ocean heating level over a 150-year period was equivalent to the explosion of 1.5 Hiroshima-size atomic bombs per second. But the heating has accelerated in recent decades and is now equivalent to 3 to 6 atomic bombs per second. The total amount of heat absorbed by the oceans over the past 150 years is 1,000 times the annual energy use of the entire population of the Earth.
The study was published in the Proceedings of the National Academy of Sciences journal and combined measurements of the ocean surface temperature since 1871 with computer models of ocean circulation.
The new work will help researchers make more accurate forecasts of sea level rise for different regions in the future.