Tropical Pacific Trade Winds Impact the Global Climate by Causing a Warming Slowdown

The trade winds are a huge part of our world's climate. Now, scientists have found shifts in Pacific trade winds actually played a key role in twentieth century climate variation, and could also influence global temperatures.

Although the amount of greenhouse gases is increasing, global surface temperatures haven't risen significantly since 2001. This seeming halt in global warming has long puzzled climate scientists. Now, though, they may have another explanation of a contributing factor.

The researchers used climate models and observations. In the end, they found evidence that the heat in global warming is going into the subsurface ocean, perhaps as a result of changes in atmospheric regulation. In fact, an earlier study pointed to unusually strong trade winds along the equator in the Pacific Ocean that are driving heat into the ocean while bringing cooler water to the surface. This, in turn, leaves less heat in the air and temporarily offsets warming from increasing greenhouse gases.

"Strong winds in the tropical Pacific are playing a role in the slowdown of warming over the past 15 years," said Diane Thompson, lead author of the new study, in a news release. "When the winds inevitably change to a weaker state, warming will start to accelerate again."

That's not to say that the winds are the only cause for this slowdown. Another reason that temperatures have leveled off could be due to increased industrialization and emissions or particles that block sunlight and exert a cooling influence. Later in the century, increased emissions of greenhouse gases played a dominant role.

"This research shows that the influence of winds on climate is not anything new. These mechanisms have been at work earlier," said Thompson. "We believe this is a significant contribution to understanding the role of natural processes in modulating global temperature change."

The findings are published in the journal Nature Geoscience.

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