Global warming pushes southern hemisphere’s westerlies farther south, with profound implications for water storage and management in South America
By Summit Voice
FRISCO — Parts of Chile and Argentina may face significant water issues as global warming pushes a belt of westerly winds farther south. Those winds are critical to maintaining the central and northern Patagonia ice fields, which maintain seasonal water storage capacity for both countries.
“We found that precipitation brought to this region by Southern Hemisphere westerlies played an important role in the glaciation of the North Patagonian Ice-Fields,” said Dr, Chris Fogwill, with the Climate Change Research Centre at the University of New South Wales.
The new research paper relies in part on a reconstruction of past changes in the North and Central Patagonian Ice-field, showing the ice field suddenly contracted about 15,000 years ago after a southerly migration of westerly winds.
This migration of westerly winds towards the south pole has been observed again in modern times and is expected to continue under a warming climate, likely leading to further ice declines in this area affecting seasonal water storage.
“Worryingly, this study suggests the region may well be on a trajectory of irreversible change, which will have profound impacts on agriculture and the increasing dependency on hydroelectric power in Chile and Argentina,” Dr Fogwill said.
The study analyzed isotope analysis to uncover changes in the ice-sheet thickness since the last major glaciation. This revealed the decline in the ice-sheet between 15,000 to 19,000 years ago.
Using a separate collection of ocean cores they were then able to determine that this decline coincided with the movement southwards of the westerlies.
The researchers found that a lack of precipitation caused by this movement, coupled with additional warming caused by rapid ice loss saw a sharp decline in glaciers with no seasonal recovery.
The southern part of the ice-field did not appear to be impacted by the movement of these winds. Instead it appeared that ocean currents and temperatures played a more important role in maintaining the ice in this section.
- Climate: How stable is the East Antarctica ice sheet? (summitcountyvoice.com)
- Weather systems clash led to India floods (bbc.co.uk)
- Climate: How fast are the ice caps really melting? (summitcountyvoice.com)