Friday, July 13, 2007

"Glacially slow" has a new meaning

Peter Hillary and Jamling Tenzing have warned that the mountain first climbed by their fathers in 1953 - Mount Everest - has been so ravaged by climate change that those men would not recognize it, The Independent (UK) reports.
The base camp where Sir Edmund Hillary] and [Tenzing] Norgay began their ascent is 40 metres lower [about 130 feet] than it was in 1953. The glacier on which it stands, and those around it, are melting at such a rate that scientists believe the mountain, whose Nepalese name, Qomolangma, means Mother of the World, could be barren rock by 2050.
And the mountain's appearance is hardly the only issue.
The rapid increase in the rate of glaciers melting - from 42 metres [138 feet] a year in the 40 years to 2001 to 74 metres [243 feet] a year in 2006 - has resulted in the formation of huge lakes in the space of a few years.

A United Nations study of the 9,000 glacial lakes in the Himalayas found that more than 200 are at risk of "outburst floods", unleashing thousands of cubic metres of water per second into an area where 40,000 people live. In 1985, Lake Dig Tsho in the Everest region released 10 million cubic metres [over 21/2 billion gallons] of water in three hours. It caused a 10-metre-high [33 foot-high] wall of water which swept away a power station, bridges, farmland, houses, livestock and people up to 55 miles downstream. Scientists estimate that the most dangerous lakes today are up to 20 times bigger. One of those, Imja Tsho, did not exist 50 years ago and lies directly above the homes of 10,000 people.
And even if that disaster is avoided, there is another:
In the longer term, scientists believe the depletion of the glaciers will drastically reduce the flow of water into the nine major rivers fed by the Himalayan glaciers.
That flow accounts for 40 per cent of the world's fresh water.

What's more, it's not just the Himalayas, it's all over the world, as a new report out of China reminds us. On Thursday, Agencie France Press said that
[m]assive glaciers in northwest China have melted at an alarming rate over the past 40 years, with global warming believed to be the culprit, scientists said in comments published Friday.

China's remote Xinjiang region is home to nearly half of the nation's glaciers that supply the rest of the country and other parts of Asia with water.

However they have shrunk by 20 percent and snow lines there have receded by about 60 metres (200 feet) since 1964, the Chinese Academy of Sciences said in a report, according to the official Xinhua news agency.
Glaciers in other regions of China and Tibet have already been reported to be shrinking dramatically - threatening floods and landslides in the short term and persistent drought in the longer term.
One of China's top glaciologists, Yao Tangdong, warned last year of an "ecological catastrophe" in Tibet because of global warming.

He said most glaciers in the region could melt away by 2100 if no efficient measures were taken.
Footnote: An odd side effect of global warming is that mountain ranges could rise more quickly without the thousands of tons of ice in glaciers pressing them down. For that and some other less-noticed effects of climate change, try this link.

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