Atlantic Warming Turbocharges the Pacific Trade Winds, Changing Weather Patterns

As our planet warms, it's changing the weather systems across the globe. Now, scientists have found that a rapid warming of the Atlantic Ocean has turbocharged the Pacific Equatorial trade winds.

The winds are currently at a level never before seen on observed records, which date back to the 1860s. Yet things aren't just windier; the strengthened winds have helped cause eastern tropical Pacific cooling and have amplified the Californian drought. In addition, the winds have accelerated sea level rise three times faster than global average in the Western Pacific.

"We were surprised to find the main cause of the Pacific climate trends of the past 20 years had its origin in the Atlantic Ocean," said Shayne McGregor, one of the researchers, in a news release. "It highlights how changes in the climate in one part of the world can have extensive impacts around the globe."

When scientists first noticed that the trade winds were intensifying, they thought it was a response to Pacific decadal variability. Yet the strength of the winds was far more powerful than expected due to changes in Pacific sea surface temperature. These changes can partly be blamed on global warming.

"The rapid warming of the Atlantic Ocean created high pressure zones in the upper atmosphere over that basin and lower pressure zones close to the surface of the ocean," said Axel Timmermann, one of the authors of the new study, in a news release. "The rising air parcels over the Atlantic eventually sink over the eastern tropical Pacific, thus creating higher surface pressure there. The enormous pressure see-saw with high pressure in the Pacific and low pressure in the Atlantic gave the Pacific trade winds an extra kick, amplifying their strength. It's like giving a playground roundabout an extra push as it spins past."

The findings are important for climate models, most of which seem to have underestimated the coupling between the two ocean basins. This could explain why models have struggled to produce the recent increase in trade wind trends.

Currently, scientists aren't sure when the Pacific cooling trend and its contribution to the global hiatus will come to an end, though the latest findings do show how much these trade winds contribute to this phenomenon.