Thursday, 27 April 2017

Global Warming

Global Warming - Heatwave Hits Chile’s Glaciers

High, high up in the Andes mountains above Chile’s capital, at the foot of the glaciers that date from the last ice age, the temperatures were almost balmy this summer. That threatens long-term water supplies to the city of seven million spread out on the plain below.

At the Olivares Alfa glacier, 4,420 meters above sea level, temperatures rose above 10 Celsius on several days in January and rarely fell below zero, said Andres Rivera, a glaciologist at the Center of Scientific Studies in Valdivia.

"It is not rare to have above-zero temperatures during summer, but high temperatures day and night, for several days in a row, that was unprecedented," Rivera said.

The glaciers that supply much of Santiago’s water over the hot, dry summer months shrunk by a quarter to 380 square kilometers in the 30 years to 2013/14, according to a study by the Universidad de Chile. The melt will accelerate if the South American nation sees more record breaking heatwaves as global warming increases. Eventually, the shrinking glaciers may force the citizens of Santiago to follow their counterparts in southern California and give up their green lawns and swimming pools.

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The Echaurren Norte glacier above the Laguna Negra reservoir has shrunk in height by the equivalent of 20 meters of water over the past 40 years, according to the government’s Water Directorate. That standard measure for glaciers means that the height of the ice has been reduced by about 25 meters since 1976.

That was before this year’s heat wave, with the glacier probably shrinking further in the past 12 months.

The worst wildfires the country has seen in generations burned 614,000 hectares of woodland and crops, dumping ash on the glaciers thousands of meters up in the Andes mountains. That meant the ice absorbed more heat, instead of reflecting it back.

Chile’s giant copper industry probably isn’t helping the glaciers either.

State-owned Codelco’s Andina copper mine and Anglo American Plc.’s Los Bronces both sit right next to the Olivares glacier system. Their operations are impacting the glaciers and the planned expansion of Andina could have an even larger effect, Ferrando said.

"The mine pit has often been drilled on both ice glaciers and rock glaciers," Ferrando said. "Trucks also lift dust that strong winds move to the glaciers and this changes the way solar radiation lands on the ice and increases the effect of heat."

The situation may be even more critical in neighboring Bolivia where glaciers have shrunk by 43 percent in 20 years, according to research by Manchester Metropolitan University. The study said new lakes have appeared as a consequence of the melting and at least 25 of them are at risk of causing floods or mudslides.

At some point soon, Latin America needs to prepare for life without glaciers.

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