Freshwater flow dominated by monsoon rains rather than glacier run-off.
Reposted from naturenews (nature.com)
Richard A. Lovett
Although global warming is expected to shrink glaciers in the Himalayas and other high mountains in Central Asia, the declining ice will have less overall impact on the region’s water supplies than previously believed, a study concludes.
It’s an important finding, says Richard Armstrong, a climatologist at the US National Snow and Ice Data Center in Boulder, Colorado, who notes that the Intergovernmental Panel on Climate Change had previously predicted dire restrictions on water supplies in Asia. “There clearly were some misunderstandings,” he says.
The researchers behind the latest study began by calculating the importance of meltwater in the overall hydrology of five rivers: the Indus, the Ganges and the Brahmaputra in India, Pakistan and Bangladesh, and the Yellow River and the Yangtze in China1. The authors found that meltwater is most important to the Indus, with a contribution roughly 1.5 times that from lowland rains. In the Brahmaputra, meltwater flow is equivalent to only one-quarter of the volume supplied by lowland rainfall, and, in the other rivers, it forms no more than one-tenth of the input.
Furthermore, the study found that in the Indus and Ganges basins, glacial ice contributes only about 40% of the total meltwater, with the rest coming from seasonal snows. In the other three rivers its contribution is even lower.
High and dry?
That’s important, says Walter Immerzeel, a hydrologist at FutureWater in Wageningen, The Netherlands, and lead author of the study1, because Asian rivers are fed by three sources: rain, snow melt and melting glaciers.
The first two are driven by current weather patterns, because rains fall either as water or as snow that will later melt. The last is a carry-over from the build-up of glaciers in prior centuries. As the glaciers shrink, their contribution will also decline until the glaciers have either melted entirely, or stabilized at smaller sizes.
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Should be AGW, of course – the problem with editing a sentence…
Steve from Rockwood says: June 11, 2010 at 9:32 am
“My understanding on India is the increasing dependence by peasants on government constructed infrastructure to draw water, rather than relying on their own means as in the past.”
Nope, exactly the opposite. The people dig their own wells and deploy ‘pony pumps’ in an uncontrolled and uncoordiated maner. This causes local and in some cases regional water supply issues and a lot of water waste. The government is trying to stop this practice so that they can have a more manageable and predicable system.
OT thought you might find this interesting.
[not unless posted in appropriate location] ~ ctm
When white water rafting in Alaska, the waters are very grey. The glaciers cut the stone and it goes downstream. In some areas I see a glacial river join a melt river and the colors take a while before they blend. Good article. Looks like if you add drama and bad consequences, it helps to get the stories printed. China is now building more dams to harness hydro energy.
RockyRoad says:
June 11, 2010 at 9:15 am
Have the climate hysterics been right about anything yet? I can’t think of a single thing. Anybody have an example where they’ve been right? I’d like to know.
“Climate change is happening”. They were right about that one. They can’t seem to get the cause, or even the direction right, but you can’t have everything.
Nature published this?
Wow…..
LarryC says:June 11, 2010 at 9:13 am
So if glaciers were in a growth phase the flow of the Indus could reduce by over 50% ?
No. My mathematical analysis: m=meltwater, s=from snow, g=glacial melting.
Indus: m= s + g where m=(60%) , g = .4(m), s= m-g.
60% X .4 = 24%
Glacial contributes only 24%
Ganges m= <10% X 40% = < 4%
All the rest are lower.
Overblown is a very moderate description of the hype.
In a similar vein I pointed this out to the alarmists over at RC sometime back. I said that melting of glaciers should at least be beneficial to animals, people and plant life down stream and that if they their melting and advanced it would not be so good for life.
Since Climategate I ‘ve been noticing a steady backtracking by alarmist scientists who seem to be employing the scientific method and applying a little more scepticism but always sprinkling the end of their reports with “climate change in the future may mean [insert alarm].”
correction:
“they reduced their melting and advanced it would not be so good for life.”
What’s a stabilized glacier? They essentially don’t grow or shrink during 10 000 years, or a 100 000 years?
I’ve always thought that glaciers are a fact due to localized weather and geographical details, and so a glacier is stabile when it grows when there’s precipitation at below zero c and shrinks even when there’s precipitation when it’s above zero centigrade.
From the full article at nature.com:
Population growth in India over the next 40 years is be expected to increase the population by about 30%, China somewhat less.
Every one of those people will be beyond the 60 million the the region can currently support… suggesting a problem that will actually affect one third of a billion people.
From the full article at nature.com:
Population growth in India over the next 40 years is be expected to increase the population by about 30%, China somewhat less.
Every one of those people will be beyond the 60 million the the region can currently support… suggesting a problem that will actually affect one third of a billion people.
Correction to the above comment:
should read
Rick says:
Right Rick! Those people who always cry wolf try to win in either case. How can people be so naive to believe the doomsayers, and give them money and grants?
NoAstronomer says:
June 11, 2010 at 8:42 am
“I don’t think glaciers really ‘stabilize’, do they? They either grow or shrink.”
I’m not a glaciologist, but I would think if a glacier is growing or shrinking very slowly it would be considered “stable”. If it was growing a little one decade and then shrinking a little the next, I’d think that would be “stable”.
90% of Himalayan Glacier Melting Caused by Aerosols & Black Carbon
Cleaning up real pollution, particularly black carbon, or soot would go a long way towards slowing the Himalayan glacial melt problem, if indeed there is one, and have the added benefit of cleaner, healthier air to breathe. It would be a win-win!
But, they don’t want to do that, because it’s completely innocent C02 they’re after.
I’m just discovering your blog and am confused…I thought you were against Nature as a publication. Why are you using it as evidence for your opinion now?
Are they redeemed when the science they present fits your expectation?
Talking about shrinkages, what if the emptying oil ridge provokes the ocean floor to collapse?
[not unless posted in appropriate location] ~ ctm
Could you identify an appropiate location for me please?
Reply: Look at the menu bar at the top of the page. Click on tips and notes. ~ ctm
Anon, why are you under the impression that this Nature article is being used as “evidence for an opinion”? I totally agree, you are confused.
Enneagram says: June 11, 2010 at 1:11 pm
“Talking about shrinkages, what if the emptying oil ridge provokes the ocean floor to collapse?”
Or worse, tip over!
Sam says:
June 11, 2010 at 8:10 am
Seems like this would be good news for policymakers, right? Less worry about how people will get freshwater. But look at this quote…
I’m not sure how a projected 40% reduction in water flow would be good for me if I were one of the policy makers in the region… Better than 100% reduction, I suppose – but that’s like telling people who “only” lost 40% of their 401(k) last year that they should be happy!
The following fact may come as a shock to global warming alarmists. Being near the very end of the present 10,500 year interglacial warmup period, glaciers continue to melt. Well, that is what glaciers are supposed do during interglacial periods. If they weren’t melting this should be of deep concern. And guess what? There are numerous glaciers around the world doing just that: growing. I would be much more worried about any growing glaciers, rather than those reaching their expected demise. Can the next 90,000+/- year ice age be at our doorstep?
Andrew30 says:
June 11, 2010 at 2:17 pm
Or worse, tip over!
Anything can happend when in bad luck! ☺
I thought I was kidding but it is not.
Gulf Oil Spill Sea Floor Collapse and Seabed Leaks May Prevent BP From Capping Well.
http://blog.alexanderhiggins.com/2010/06/09/gulf-oil-spill-sea-floor-collapse-seabed-leaks-prevent-bp-capping-2/