June 11, 2010

As Himalayan Glaciers Melt, Food Shortages Expected

A study released Thursday reports that about 60 million people living throughout the Himalayas would suffer food shortages in the coming decades as glaciers shrink and the water sources for crops dry up.

However, Dutch scientists said the impact would be much less than previously estimated a few years ago by the UN Intergovernmental Panel on Climate Change.  The UN report in 2007 warned that hundreds of millions of people were at risk from disappearing glaciers.

Scientists said the reason for the discrepancy is that some basins surrounding the Himalayas depend more on rainfall than melting glaciers for their water sources.

Countries like the Indus, Ganges and Brahamaputra basins in South Asia that depend heavily on glaciers could see their water supplies decline by as much as 19.6 percent by 2050.  China's Yellow River basin, in contrast, would see a 9.5 percent increase precipitation as monsoon patterns coould change due to the changing climate.

"We show that it's only a certain areas that will be affected," said Utrecht University Hydrology Prof. Marc Bierkens, who along with Walter Immerzee and Ludovicus van Beek conducted the study. "The amount of people affected is still large. Every person is one too many but its much less than was first anticipated."

The study is one of the first to examine the impact of shrinking glaciers on the Himalayan river basins.  It will likely further add to the increasing burden that climate change will devastate the river basins that are mostly located in India, Pakistan, Nepal, Bangladesh, Bhutan and China.

For the most part, scientists agree glaciers are melting at an accelerated rate as temperatures increase.  Most say that warming is directly linked to higher atmospheric concentrations of greenhouse gases like carbon dioxide.

Glaciers like the ones in the Himalayas could hold out for centuries in a warmer world.  However, according to researchers in the U.S. and Europe, over 90 percent of glaciers around the world are in retreat, with major losses already seen across much of Alaska, the Alps, the Andes and numbers of other ranges.

Some scientists have come under scrutiny after a 2007 UN report included several errors that suggested the Himalayas could disappear by 2035.  The mistake was that the year 2350 was transposed as 2035, which opened up a door of skepticism from climate change critics.

The findings by the Dutch teamn reported in the journal Science, were greeted with caution by glacial experts who did not take part in the research.  The team said that the 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.

Director of the Tianshan Glaciological Station in China, Zhongqin Li, told the Associated press (AP) that the study omitted several other key basins in central Asia and northwest China, which will be hit hard by the loss of water from melting glaciers.

Several of these outside researchers said the findings should reaffirm concerns that the region will suffer food shortages due to climate change, exacerbating already existing concerns like overpopulation, poverty, pollution and weakening monsoon rains in parts of South Asia.

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

"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," he said.

"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."

The researchers said governments around the area should adapt to the projected water shortages by shifting to crops that use less water, engaging in better irrigation practices and building more and larger facilities to store water for extended periods of time.

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


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