Climate Change May Lead to Critical Water Shortages for South America
As global temperatures continue to rise, Chile and Argentina may face critical water storage issues as rain-bearing westerly winds over South America's Patagonian Ice-Field move south, a new study by University of New South Wales researchers found.
In reconstructing past changes in the North and Central Patagonian Ice-Field, which plays a vital role in the hydrology of the region, the scientists found that the ice field suddenly contracted around 15,000 years ago after a southerly migration of westerly winds -- a migration that is once again occurring and expected to worsen under a warming climate, scientists warn.
As this happens, the study explains, further ice declines in the area affecting seasonal water storage are likely to occur.
"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," Chris Fogwill from the school's Climate Change Research Center said in a press release, adding that their research shows that "this ice-field significantly reduced in size when those winds moved southwards."
Meanwhile, Fogwill stressed, the North Patagonian Ice-Field is vital in maintaining seasonal water storage capacity for Argentina and Chile.
"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," Fogwill said.
The team used rare isotopes to uncover changes in the ice-sheet thickness since the last major glaciation period in order to demonstrate the importance of the winds on the ice-sheets and consequent water supply. In doing so, they revealed the decline in the ice-sheet between 15,000 to 19,000 years ago.
Then, using a separate collection of ocean cores, they were then able to determine that this decline coincided with the southward movement of the westerlies.
In the end, the team of researchers determined 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 scientists were surprised to find, however, that the southern part of the ice-field did not appear to be impacted by the movement of these winds; rather, the evidence points to ocean currents and temperatures as having played a more important role in maintaining the ice in this region.
Ultimately, Fogwill concluded, the "ice-field in the Northern and Central region of the Patagonian ice-field are highly sensitive to precipitation and need this to remain healthy."