Millions of people living in and below the Himalayas are facing potential disaster, according to a report recently in Nature magazine. The magazine said there has been a tenfold increase in events such as the 1985 destruction of the village of Ghat in Nepal.
In that instance, a lake high in the mountains became swollen with glacier meltwater and burst its banks, sending a torrent of water plunging down the mountainside, destroying everything in its path.
Scientists say more and more Himalayan glacier lakes are filling up with increased melted ice, and at least 24 are poised to escape their banks in Bhutan, with a like number ready to burst out in Nepal.
Natures report said that is only the start. Future disasters in the Himalayas, it said, will include floods, droughts, land erosion, biodiversity loss and changes in rainfall and the monsoon.
Eventually, say scientists, the Himalayan glaciers will shrink to the point that their meltwaters will dry up. At the same time, rivers like the Indus, Yellow River and Mekong River will become mere trickles. Water for drinking, cooking, washing and irrigation will vanish. Hundreds of millions of people will be affected.
Dr. Phil Porter of the University of Hertfordshire in England said: There is a short-term danger of too much water coming out of the Himalayas and a greater long-term danger of there not being enough. Either way, it is easy to pinpoint the cause: global warming.
The magazine report said temperatures in the mountainous region have risen by more than 1 degree centigrade recently and will rise another 1.2 degrees by 2050, reaching 3 degrees Celsius by the end of the century.
A glacier lake catastrophe happened once in a decade 50 years ago, said John Reynolds, a British geologist whose firm advises Nepal. Five years ago, they were happening every three years. By 2010, a glacial lake catastrophe will happen every year.
These overflows can threaten more than villages. A similar lake which burst near Machu Picchu in Peru recently destroyed an entire hydro-electric plant. The same thing is waiting to happen in Nepal, Reynolds said.
But its not only Nepal and Bhutan that are under threat from melting glaciers. In 2003, a team of researchers reported that glaciers were melting so fast in parts of Kazakhstan in central Asia that the livelihoods of millions of people were likely to be affected. The scientists said the glaciers in the area lost nearly 2 cubic kilometers of ice yearly in the latter part of the 20th century.
There are 416 glaciers in the area, covering 197 square miles. Between 1974 and 1990, according to the BBC report, the glaciers lost 1.28 percent of their volume annually.
Last year, a team of scientists spent three months in the Antarctic and found a key glacier in the center of the Southern Ocean is melting far faster than anticipated. They also found Brown Glacier is melting faster than they expected. It had lost half-a-meter of ice yearly in the 50 years before 2000. Now, Australian Broadcasting Co. reported, the melt rate is four times that.
The story is very similar in Argentina and Chile, where glaciers are melting twice as fast as they were in 1975, according to Britains The Guardian.
Researchers, led by Eric Rignot of the Jet Propulsion Laboratory in Pasadena, Calif., said the Patagonian glaciers [at the tip of South America] accounted for 9 percent of glacial contribution to sea level increases, while those in Alaska were behind sea level rises of 30 percent. Still, in Patagonia the area covered by glaciers was five times smaller than that in Alaska.
Rignots team said Patagonias greater vulnerability to climate change was because of the glaciers higher turnover rates and a dominance of calving glaciers.
From the Nov. 23-29, 2005, issue