… although you might have heard otherwise. Over the past decade, scientists have been puzzling over an apparent “pause” in the warming of the Earth’s surface. Instead of going up quickly, as climate models predicted, temperatures appeared to have slowed.
We now know that most of that missing heat is going into the oceans, which are warming up, driven by faster winds at the sea’s surface. Scientists have found that the Pacific Ocean trade winds that blow along the equator from east to west have been speeding up since the early 1990s. They don’t just push heat into the ocean depths, they’re also increasing sea level rise in the western Pacific, and cooling waters in the east, which is partly responsible for California’s dire drought situation.
But what’s causing the winds to speed up?
Research published in Nature Climate Change today points the finger at the Atlantic Ocean. There, the sea’s surface is warming up – and fast. That warming causes the air above to rise. It then cools and descends over the Pacific Ocean, and when it does it drives the trade winds faster.
Dr Shayne Macgregor at the ARC Centre of Excellence for Climate System Science at the University of New South Wales said the study “highlights how changes in the climate in one part of the world can have extensive impacts around the globe.”
But don’t expect the reprieve to last, warn the scientists. The cooling trend is likely to end, perhaps triggered by a serious El Nino, and when it does we can expect warming to return with a vengeance.
Bill Condie is a science journalist based in Adelaide, Australia.
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