Perito Moreno glacier thrives despite global warming

[Mark]

Climate change appears to be helping Argentina's mighty Perito Moreno glacier, which is thriving in defiance of the global warming that is shrinking its peers.While most of the world's glaciers are melting away because of warmer temperatures, scientists say the ice field, known as "The White Giant", is gaining as much as three metres a day in some parts, pushed forward by heavy snowfalls in the Patagonia region.

"Glaciers don't respond solely to temperature changes," says Martin Stuefer, a Patagonian expert from the University of Alaska Fairbanks. He says the area's heavy precipitation has apparently increased, combining with strong, cold Patagonian winds to reinforce the glacier.

"Climate change is not the same everywhere," says Stuefer. The creaking Perito Moreno is one of the largest glaciers in South America located 3000 kilometres southwest of Buenos Aires. Visitors crowd onto boats and viewing platforms to see the 30 kilometre long glacier noisily hurl huge blocks of blue-tinged ice into Lake Argentino.

Melting the norm

Scientists say nearly 90% of the glaciers in Antarctica and Patagonia - at the southern tip of South America - are melting quickly. he same is happening in the Arctic, the Andes, the Alps, the Himalayas and elsewhere in response to climate change linked to human activity.

The average melting rate of the world's mountain glaciers has doubled since the year 2000, say the Environment Programme and the World Glacier Monitoring Service in a recent report. Melting glaciers threaten to cause rising sea levels and dry up steady sources of fresh water that people now depend on for farming, drinking and hydropower.

But glaciers are also affected by other factors such as snowfalls, winds, altitude and shade, and the Perito Moreno is among the few resisting the broad trend.

"A small percentage seems to be doing strange things," says David Vaughan, a British Antarctic Survey glaciologist and member of the United Nations climate panel. "The odd 13% are either stable or advancing a little."

There are limits to the Perito Moreno's aggressive advance. It periodically reaches as far forward as it can toward the Magallanes Peninsula and then sheds a large section of its front in a spectacular phenomena known as "la ruptura" - the rupture.


Source: ABC Science