zondag 3 november 2013

Global Water Crisis

  • Global water crisis: too little, too much, or lack of a plan?

The global water crisis – caused by drought, flood, and climate change – is less about supply than it is about recognizing water's true value, using it efficiently, and planning for a different future, say experts.

By William WheelerContributor / December 2, 2012
Global water crisis: This article is part of the cover story package for the Dec. 3 issue of The Christian Science Monitor Weekly magazine. A girl looks at water from the Nile flowing from a pump in the Manshiyet Nasser shantytown in eastern Cairo in this file photo.
Amr Abdallah Dalsh/Reuters/File
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For most of history, thirsty humans made do with what moisture fell from above: The sun warmed the salty seaspure water evaporated into the air and then cooled and fell to the earth as precipitation. There it clung to glaciers, froze and thawed in lakes, was absorbed by plant roots, coursed through fractured bedrock, and seeped slowly through soil, into aquifers. Most of it returned to sea and sky all over again. There is as much of that water on the planet today as when the first amphibian flopped ashore; as much as when the ancient Greeks divined the future in the babble of brooks.
So why do experts in science, economics, and development warn that a "global water crisis" threatens the stability of nations and the health of billions?
From space, the idea of a global water crisis may seem perplexing: 75 percent of the planet's surface is blue. But usable fresh water is a tiny fraction of what we see – only 2.5 percent of the water on Earth. And two-thirds of that fresh water is locked away in glaciers, icecaps, and permanent snow. Of the stock of accessible fresh water, 99 percent is in underground aquifers – some are nonrenewable; and in some that are replenishable, ground water is slurped up faster by a growing population than it can be replaced.
But even so, say experts, the problem is perhaps more an issue of recognizing water's true value, using it efficiently and planning for the lean times, than it is a lack of overall supply.
The ongoing historic American drought, with its cascade effect on food and utility prices at home and food costs abroad, is an example of scarcity's effect.
But superstorm Sandy's deluge and flooding, says Geoff Dabelko, an environmental expert at Ohio University in Athens, is an example of how the term "global water crisis" can be misleading. It tends to imply that there's just one kind of crisis – a water shortage.
"The kind of dead-cow-carcass-in-the-desert image that global 'water crisis' evokes is very real for some people," Professor Dabelko says. "But there are so many dimensions." Too much water – whether from flooding, sea level rise, or more extreme storms – can be just as deadly as too little.
While the balance between water supplies and the demands of a burgeoning population are further complicated by the effect of climate change on delicate hydrological margins, there are those who say there is enough water, if nations learn to plan for a different future – one in which past abundance is no guide.
The growing thirst for water
Water is a part of everything we do: It feeds crops, powers cities, cools computer servers, and is key to the manufacturing of everything from clothes to cars. The billion more people expected on the planet by 2025 will increase water demand for all of those functions. And just to feed those people, water withdrawals for agriculture are expected to increase by about half.
But it's not only about the additional mouths to feed; it's also the growth of new appetites. Much of the growth in demand will emerge from the swelling sprawl of bustling, slum-pocked metropolises across the developing world. For the first time in history, the share of the global population living in cities recently surpassed 50 percent – on its way to 75 percent expected by 2050.

2 opmerkingen:

Anoniem zei

Warming report sees violent, sicker, poorer future
http://www.newsdaily.com/article/9cb5e68c0c9589c5b1e2cde79cc13dbe/warming-report-sees-violent-sicker-poorer-future
Wo the f**k needs artificial intelligence...
http://www.newsdaily.com/article/12f7db661ff208fa1e84ebdef809cd7a/computer-cracks-captchas-in-step-toward-artificial-intelligence

Anoniem zei

Water kruipt waar het niet gaan kan. Gehandicapte allochtoon in brand gestoken in Engeland.
"A modern British murder: Vigilante neighbours face jail after convictions over murder of disabled man Bijan Ebrahimi wrongly accused of paedophilia " http://www.independent.co.uk/news/uk/crime/a-modern-british-murder-vigilante-neighbours-face-jail-after-convictions-over-murder-of-disabled-man-bijan-ebrahimi-wrongly-accused-of-paedophilia-8909228.html

Peter Flik en Chuck Berry-Promised Land

mijn unieke collega Peter Flik, die de vrijzinnig protestantse radio omroep de VPRO maakte is niet meer. ik koester duizenden herinneringen ...