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Wheat crops in India  (Source: NY Times)
Populations around the Himalayas at risk

recent study in the journal Science shows that the shrinkage of glaciers will cause a lack in water sources for crops, ultimately leading to food shortages for approximately 60 million people living near the Himalayas. This study is one of the first to observe the effect melting glaciers have on the Himalayan river basins, and could possibly further provoke the existing debate that climate change will destroy river basins located mostly in Pakistan, Bangladesh, India, Nepal, China and Bhutan.

Dutch scientists Marc Bierkens, Walter Immerzee and Ludovicus Van Beek – who conducted the study and wrote in the journal -- concluded that basins around the Himalayas such as the Indus, Ganges and Brahamaputra depend on the melting glaciers to water their crops, and could see a 19.6 percent decline in their water supply by 2050. 

"We estimate that the food security of 4.5 percent of the total population will be threatened as a result of reduced water availability," the researchers wrote. "The strong need for prioritizing adaptation options and further increasing water productivity is therefore eminent."

This new study largely contrasts the U.N. report in 2007, where the U.N. Intergovernmental Panel on Climate Change estimated that hundreds of millions of people were in danger from the receding glaciers. According to the scientists, the reason for the "discrepancy" is that only some basins in this area depend on the glaciers. Others, such as China's Yellow River basin, obtain their water from rainfall and are expected to see a 9.5 percent increase in water supply due to the changing climate altering the pattern of monsoons. 

"We show that it's only certain areas that will be affected," said Bierkens. "The amount of people affected is still large. Every person is one too many but it's much less than was first anticipated."

In addition, the U.N. report included other errors such as the Himalayas disappearing by 2035, when actual data indicates that this will happen by 2350. Client change skeptics attacked this inaccuracy, which in fact, was just a mistake in transposing the numbers. 

Most scientists agree that "glaciers are melting at an accelerated rate as temperatures increase," and that the reason is related to the higher "atmospheric concentrations of greenhouse gases such as carbon dioxide." Evidence for this appears in the considerable losses seen in glaciers across the Andes, Alaska, the Alps and several other ranges. According to researchers in the United States and Europe, "more than 90 percent of glaciers worldwide are in retreat."

Researchers who did not take part in the study, such as Zhongqin Li, director of the Tianshan Glaciological Station in China, noted that the scientists performing the study disregarded many other basins in central Asia and northwest China which will be affected by the glacial losses. Other glacial experts and scientists warned that "uncertainties and lack of data for the region makes it difficult to say what will happen in the next few decades to the water supply." While many researchers are skeptical of exact numbers in the study, they do agree that there should be a concern for those living in the glacial-dependent basins due to climate change. In addition, problems like pollution, overpopulation and poverty are added stress to the situation.

"The paper teaches us that there's a lot of uncertainty in the future water supply of Asia and within the realm of plausibility are scenarios that may give us concern," said Casey Brown, an assistant professor of civil and environmental engineering at the University of Massachusetts. 

"At present, we know that water concerns are already a certainty - the large and growing populations and high dependence on irrigated agriculture which makes the region vulnerable to present climate variability. 

"This paper is additional motivation to address these present concerns through wise investments in better management of water resources in the region, which for me means forecasts, incentives, efficiency."



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RE: But...
By drycrust3 on 6/11/2010 4:25:50 PM , Rating: 2
Here is a different link to what looks like the same report.
http://www.newscientist.com/article/dn19029-himala...

I think this is a load of nonsense.

quote:
The model shows that the Indus and the Brahmaputra rely most on glaciers: meltwater accounts for 60 per cent of water carried by the Indus and 20 per cent of that in the Brahmaputra, but less than 10 per cent of the Ganges, Yangtze and Yellow rivers comes from melted ice. Rainfall makes up the rest.


quote:
These results would suggest that the Indus and Brahmaputra will be hardest hit by climate change – but taking into account changes in rainfall patterns with climate change causes a different pattern to emerge, says Immerzeel.
To make up for this, he fed temperature, rainfall and snow projections into his model. He found that by 2050, the upstream flow of the Brahmaputra and Indus could shrink by 19.6 per cent and 8.4 per cent respectively, despite 25 per cent more rain.


So on the one hand we have less snow, but on the other hand we have more rain? And when they say "rain" do they mean the annual monsoon season is the same length but has 25% more downfall, or do they mean the 25% is outside of the annual monsoon season?
My guess on all this is the 25% more rain will fall on the arable land which means the farmers will be better off, not worse off.


RE: But...
By ninus3d on 6/11/2010 4:48:07 PM , Rating: 2
I think this is due to the fact that no glacies means no STEADY access to freshwater you currently have from freshwater glacierlakes etc. And while it may still rain, and on a yearly basis you may end up having even a bigger volume of water spewed over your lands, you dont necessarily have wateraccess when you actually need it.


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