Due to human-induced climate change, scientists have found that the westerly wind drift is accelerating near Antarctica.

The west wind drift is a sea current that runs eastwards around Antarctica. It is one of the world’s strongest movements. Thanks to ingenious technology, scientists are now able to map the ins and outs of this powerful ocean current. And that leads to a surprising discovery.

West wind drift

The westerly wind drift completely surrounds Antarctica, separating cold water to the south from warmer subtropical water just to the north. This warmer part of the Southern Ocean absorbs much of the heat pumped into the Earth’s atmosphere by human activities. For this reason, scientists consider it vital to understand the dynamics of ocean currents. Because what happens here can affect the climate elsewhere.

The west wind drift. Image: NASA

ocean floats

In a new study, researchers used satellite measurements and data from Argo, a fleet of nearly 4,000 automated floating buoys scattered across all oceans, to gauge west wind drift. These ‘ocean floats’ have been measuring ocean temperature, salinity, currents and, increasingly, chemical and biological components since the beginning of the new millennium. Thanks to the extensive Argo network, the researchers were able to analyze more than a decade of data to find out whether the westerly wind drift has changed in the meantime.

More about Argo
The Argo network is a particularly big step forward. Before 2000, researchers were dependent on instruments that were much less precise. As a result, the data, and the studies based on it, were also uncertain. However, Argo was created in 2000. 4,000 bobbing robots now dive every few days to measure temperature, pH and salinity, among other things. This provides scientists with consistent and comprehensive data on the state of our ocean. This shows, for example, that the seas are warming quickly.

Researchers unleash an Argo float in the Southern Ocean. Image: Isa Rosso/SOCCOM

And that indeed turns out to be the case. The researchers find that one of the most powerful ocean currents on Earth suddenly appears to be in much more of a hurry: the westerly wind drift is flowing much faster today than it was a decade ago. “This acceleration facilitates the exchange of heat or carbon between ocean basins,” said study researcher Jia-Rui Shi.


The fact that the west wind drift is flowing faster today is mainly due to ourselves. The researchers argue that climate change is to blame. That’s because ocean currents capture most of the man-made heat. And when the difference between hot and cold water increases, the currents between those two masses speed up. “Both observations and models show that ocean heat change causes the significant acceleration of ocean currents,” said Shi. And that is quite a surprising discovery. The west wind drift is usually driven by wind. “But we show that surprisingly, changes in speed are mainly due to changes in the heat gradient,” said study researcher Lynne Talley.

It means that, thanks to decades of observations, the research team has uncovered a crucial trend that had been hidden from scientists until now. It may not even stop there. The researchers suspect that the speed of the westerly wind drift will increase further as the Southern Ocean continues to absorb more of the heat emitted by humans.