Shrinking glaciers won't affect South Asia water availability: study

Aug 05, 2013
The Khumbu Glacier at Everest-Khumbu region on May 11, 2009, one of the longest glaciers in the world. Glacier systems that feed two key rivers in South Asia will badly retreat this century, but demands for water are still likely to be met, a study predicted on Sunday.

Glacier systems that feed two key rivers in South Asia will badly retreat this century, but demands for water are still likely to be met, a study predicted on Sunday.

The health of in the Himalayas is a closely-watched issue, as they supply vital to a region facing surging population growth and rising demands for food.

Scientists agree that the onward march of the will shrink the glaciers, but there is little consensus on the volume and rate of ice loss and the impact on water availability.

In a fresh attempt at clarity, Dutch scientists led by Walter Immerzeel at Utrecht University carried out a high-tech computer simulation of what could happen to two glacial watersheds—the Baltoro, which drains into the Indus, and the Langtang, which feeds the Ganges—in the light of two scenarios for global warming, comprising a modest and a strong rise in temperatures.

The two glaciers will shrink badly: by 2100, they will lose roughly half their volume under the higher warming scenario.

But, at least as far as this century is concerned, water users will not experience scarcity, in part because the extra meltwater will help meet rising needs.

An Indian youth jumps from the from Shashtri bridge into the River Ganges in Allahabad on August 1, 2013. Glacier systems that feed two key rivers in South Asia will badly retreat this century, but demands for water are still likely to be met, a study predicted on Sunday.

"In both cases, glaciers will retreat but net runoff is on a rising limb at least until 2050," according to the paper in Nature Geoscience.

"In combination with a positive change in precipitation, this century is not likely to decline. We conclude that that depend on monsoon rains and glacier melt will continue to sustain the increasing water demands expected in this area."

Other studies have suggested a reduction in future runoff in the Indus and Ganges basins, but these have looked at the region on a large scale.

The new study is a more useful prediction because it deals with regional hydrology in much finer detail, say its authors.

They note that 70 percent of the rainfall that feeds the Ganges and Brahmaputra occurs during the monsoon season, which coincides with the main period for glacier melt and and a wet downstream climate. This means a surge of water is available for capture in reservoirs, and can be released to meet later demand downstream, the paper says.

Explore further: NASA balloons begin flying in Antarctica for 2014 campaign

More information: Nature Geoscience DOI: 10.1038/ngeo1896

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alfie_null
4 / 5 (4) Aug 05, 2013
When you try to project so far into the future, one wildcard is any sort of advance in technology. 2100 is almost 90 years away. If we (in the United States) tried to live off the land today as we did 90 years ago, it would not be possible. Extrapolating the water use and food production practices of that era would not have produced useful results (for today).
NikFromNYC
2.1 / 5 (10) Aug 05, 2013
IPCC Glaciergate: loss by 2035 was reported instead of 2305, based on a non-peer reviewed magazine article.
IPCC Himalayagate: prediction of ice loss were basically made up in a WWF pamphlet.
IPCC Greenpeacegate: a Greenpeace official was a lead author on the renewable energy chapter, one who cited his own non-peer reviewed work published with a green energy lobby foundation.
IPCC Amazongate: up to 40 per cent loss of the Amazon rainforest due to AGW was based on a WWF pamphlet about the effects of logging.
IPCC Seagate: claimed that 55% of the Netherlands is below sea level, versus the real value of 26%.
IPCC Africagate: claim that yields from agriculture could be reduced by up to 50 percent by 2020 were based on a pamphlet a by a Canadian advocacy group, written by an obscure Moroccan academic who specialises in carbon trading.
IPCC Pachaurigate: the IPCC chairman was found to be deeply involved in carbon trading schemes, as a chairman of the board of many green energy companies.
NikFromNYC
2.4 / 5 (8) Aug 05, 2013
Background info, namely a map of world ice masses that shows the Himalayas are but 1% of continental ice:

http://oi52.tinyp...6cup.jpg

"In some cases, soot – the fine, black carbon silt that is released from stoves, cars and manufacturing plants – can pack more of a climatic punch than greenhouse gases, according to a paper published in the journal Atmospheric Chemistry and Physics."
NikFromNYC
2.1 / 5 (7) Aug 05, 2013
Sorry, Phys.org deletes multiple links and nearby paragraphs if you edit a post. Their edit box can't be resized on my iPhone browser, either.

Soot link about the complexities of polluted Asian and Indian air that causes glacier melting:

http://esciencene....climate
antialias_physorg
2.3 / 5 (3) Aug 05, 2013
Extrapolating the water use and food production practices of that era would not have produced useful results

Since we don't know how many people will be dependent on this water source it's hard to estimate whether it will meet demands.

On the other hand one can't really force glaciers to melt any faster - so the water that is there from that source (and is projected to be there) won't fluctuate much.

Then again: climate change affects also other sources of water (rain, and to a lesser extent groundwater levels) - so whether the total amount of water available will be sufficient is an unanswerable question.

Once the glaciers run dry, then we can pretty much guarantee that there will be problems (to put it mildly. 'Water wars' more likely). So it's no good pretending that "all will be fine for the next 100 years". The earlier we start to take action the less costly (and invasive) it will be.
NikFromNYC
2 / 5 (8) Aug 05, 2013
"So it's no good pretending that "all will be fine for the next 100 years". The earlier we start to take action the less costly (and invasive) it will be."

Said by the same bleeding heart type of activist who shot George Jetson and family out of the sky by scuttling the ultra low emissions Atomic Age. Since soot is the root cause of Himalayan glacier melting and the best replacement for lost water is nuclear powered desalination plants, massive focus on junk science policy represents a loss of ability to do good instead of further harm. When the near trillion dollars already funneled away from basic science R&D into Enron schemes and Solyandra scams suddenly presents itself as a severe lack of new antibiotics, billions will suffer. Thousands of hard science graduates are now unemployed, as Global Warming money continues its gold rush tulip craze.
antialias_physorg
3.7 / 5 (3) Aug 05, 2013
Since soot is the root cause of Himalayan glacier melting and the best replacement for lost water is nuclear powered desalination plants

Sort of bizarre how some people still think: if we don't do nuclear - we have to do coal.

Hello? Have you been awake during any part of the, oh, last fifty years? There's plenty of alternatives around that don't have the drawbacks of either.

When the near trillion dollars already funneled away from basic science R&D into Enron schemes and Solyandra scams suddenly presents itself as a severe lack of new antibiotics, billions will suffer

Hyperbole much? Check your numbers. They're laughably inaccurate (so far as that i would claim that you just made them up 5 minutes ago). Science site, remeber? That type of ad-hoc-fabrication will just eran you ridicule.
Thousands of hard science graduates are now unemployed

BS. If you're a hard science graduate (and good at what you do) then you have no problem finding a job.

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