News / Science & Technology

Climate Change Affecting Water Resources

The sun is seen behind smoke billowing from a chimney of a heating plant in Taiyuan, Shanxi province December 9, 2013.
The sun is seen behind smoke billowing from a chimney of a heating plant in Taiyuan, Shanxi province December 9, 2013.


Joe DeCapua
Scientists say climate change will not affect all regions of the world equally – especially when it comes to fresh water. The latest computer models indicate some places will get a lot less, while others get a lot more.

Dr. Jacob Schewe and his colleagues say that “water scarcity is a major threat for human development” if greenhouse gas emissions remain unchecked. They’ve published their findings in a special issue of the Proceedings of the National Academy of Sciences.

“The reason we’re concerned is that it’s a very important issue for a lot of people. We all depend on water for so many different purposes," he said. "And water scarcity, where it exists, really impairs many things that people do and that people live on.”

Schewe works at the Potsdam Institute for Climate Impact Research. He said the “steepest increase of global water scarcity” could happen if global warming rises two to three degrees Celsius above pre-industrial levels. That could happen, he said, in the next few decades.

“Under climate change, patterns of precipitation, patterns of temperature, of evaporation, and all these variables are going to change. And that means changes will occur in the hydrological cycles and the water cycle of the planet," he said.  "And it will of course affect the availability of water around the world. So the question is in which way it will affect the water availability and will it make water even more scare in a given region, in a given place or will it lead to more water being available?”

Schewe gives some examples of where he believes the computer models are accurate.

“One example,” he said, “is the Mediterranean region. Most of the models really project a strong drying. So much less water being available. That’s mainly southern Europe, northern Africa. So these places will be affected most probably by a reduction in water availability. Another strong signal in the opposite direction is in the high northern latitudes, so, Siberia, northern Canada. These places will probably get more water.”

He said countries such as Israel, Turkey, Spain and Morocco could see as much as a 50-percent reduction from what they have now.

Findings given a medium to high confidence rating indicate that the southern United States will become drier. But there are many areas where the models disagree. And it can be difficult to develop a model that fits a particular region. One such region is West Africa’s Niger Delta.

Nevertheless, Schewe said he hopes policymakers take notice of the findings so far.

“One thing that we hope will happen is that not only national policymakers will consider them, but actually also the people who are busy with the policy negotiations about climate change mitigation. The best way to cope with it is simply not to let it happen, right? And you can still avoid a lot of these changes by simply mitigating climate change,” he said.

Agriculture is the biggest consumer of freshwater.

He said, “if you have a country that depends a lot on agriculture, where you’ve got a lot of agriculture, and you see that the water resources will go down in the future, then maybe now you still have some time to find the resources, find the funding, develop the technologies or buy the technologies and to use the water more efficiently. And also, to put regulations in place to avoid overuse of the resources -- and to distribute it evenly across the different users.”

Schewe is calling on more researchers to develop climate change models.

Co-author, Dr. Pavel Kabat – of the International Institute for Applied Systems Analysis – said if human-made climate change continues the very basis of life for millions of people will be put at risk – even under the more optimistic scenarios and models.

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Comment Sorting
by: Scott Eastman from: Utah, USA
January 07, 2014 2:01 PM
Just like the "hole in the ozone" scare! You hardly hear of it anymore. According to the experts it takes 25-30 years for the chlorine/fluorine molecules to get from the source on the ground to the area where it damages the ozone. Beginning in 1994 when recovery was mandated and then certain refrigerants outlawed, it would suggest that the ozone should be at it's most depleted stage. Yet we haven't seen the affects predicted by the models. The only thing to come of all that hype is the huge profits of Dupont and other chemical giants. R-22 could be purchased for less than $1.00 per lb and now sells for more than $18.00 per lb. If this wasn't the most costly screw job to the public, I would like to know what was!

by: dreamcat from: USA
December 23, 2013 4:56 PM
This is not all human made. It is caused by the sun. Read this book Forgotten civilization : the role of solar outbursts in our past and future / Robert M. Schoch, Ph.D. to see that as short a time ago as 12,000 BCE, the sun caused this type of problem on earth. The green fairy tale put out is just to get money out of us. The science is not definite and not there in many cases.
In Response

by: Cameron L. Spitzer
December 26, 2013 3:28 PM
Variation in solar output (the "solar constant") contributed less than 5% of the global warming over the last century. Sunspots, flares, and CMEs contributed essentially zero. There's no controversy in science about any of that. If Dreamcat knew any scientists, or had ever worked in the hard sciences, he'd know that old lie "scientists lie to get grants" is a preposterous conspiracy theory. Scientists compete to discover each other's mistakes. False science goes far on the Limbaugh show, but it goes nowhere in real life.

by: Stan EV from: NV, USA
December 23, 2013 12:55 PM
It would be good if people would actually take mass action after reading articles like this....unlikely.

Get out of your car, walk, bike, ebike, transit or EV about.

Most likely, new property for sale in Alaska, Canada and Siberia.

by: Kitagawa Keikoh from: Daikanyama, TKO
December 20, 2013 7:19 PM
I think it's very understandable that the water availability will change in the future because of the planet scale climate change. That's why we have desert area and water rich area now, and of course these area will be shifted in the far future by the global climate change.

That change will occur in the very long time, so we human can adopt it gradually and there is no need to use any technologies to adopt it.

Poor scientists always scare us using the phrase "climate change" or "global warming", but it means nothing.
In Response

by: Annabel Sanchez from: Argao, Cebu, Philippines
December 22, 2013 6:12 PM
I've kept track on Limate Change issue at VOA like Global warming in the pacific and those discussed in Poland. I find it very alarming! Glad to say that I've planted a hundred pots of Mahogany which are at 2 years now that will soon generate oxygen.

Annabel C. sanchez
Lapay, Argao, Cebu, Philippines

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