More Than 500 Million People Might Face Increasing Water Scarcity
09 October, 2013
Scarcity and contamination of water is taking a toll on people, especially the poor around the world. The regions at risk under unabated global warming include the grasslands of Eastern India and the shrublands of the Tibetan Plateau.
Both freshwater availability for many millions of people and the stability of ecosystems such as the Siberian tundra or Indian grasslands are put at risk by climate change while contaminated water breeds low-weight babies, sometimes born prematurely. 
A number of studies have found:
Even if global warming is limited to two degrees above pre-industrial levels, 500 million people could be subject to increased water scarcity -- while this number would grow by a further 50 percent if GHG emissions are not cut soon. At five degrees global warming almost all ice-free land might be affected by ecosystem change.
"We managed to quantify a number of crucial impacts of climate change on the global land area," says Dieter Gerten, lead-author of one of the studies.
"The increase in water scarcity that we found will impact on the livelihoods of a huge number of people, with the global poor being the most vulnerable," says Hans Joachim Schellnhuber, one of the co-authors and director of PIK. This might get buffered to some extent through adaptation measures such as expanding of irrigated cropland. However, such an expansion would further increase the pressure on Earth's ecosystems and water resources. "Now this is not a question of ducks and daisies, but of our unique natural heritage, the very basis of life. Therefore, greenhouse-gas emissions have to be reduced substantially, and soon."
Mean global warming of 2 degrees, the target set by the international community, is projected to expose an additional 8 percent of humankind to new or increased water scarcity. 3.5 degrees -- likely to occur if national emissions reductions remain at currently pledged levels -- would affect 11 percent of the world population. 5 degrees could rise this even further to 13 percent.
"If population growth continues, by the end of our century under a business-as-usual scenario these figures would equate to well over one billion lives touched," Gerten points out. "And this is on top of the more than one billion people already living in water-scarce regions today." Parts of Asia and North Africa, the Mediterranean and the Middle East are particularly vulnerable.
Greater changes ahead
For the green cover of our planet, even greater changes are in store.
"The area at risk of ecosystem transformation is expected to double between global warming of about 3 and 4 degrees," says Lila Warszawski, lead author of another study that systematically compared different impact models -- and the associated uncertainties -- in order to gain a fuller picture of the possible consequences of climate change for natural ecosystems. This is part of the international Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP).
A warming of 5 degrees, likely to happen in the next century if climate change goes on unabated, would put nearly all terrestrial natural ecosystems at risk of severe change. "So despite the uncertainties, the findings clearly demonstrate that there is a large difference in the risk of global ecosystem change under a scenario of no climate change mitigation compared to one of ambitious mitigation," says Sebastian Ostberg, lead author of the third study.
The regions at risk under unabated global warming include the grasslands of Eastern India, shrublands of the Tibetan Plateau, the forests of Northern Canada, the savannas of Ethiopia and Somalia, and the Amazonian rainforest. Many of these are regions of rich and unique biodiversity.
The combined changes to both water availability and ecosystems turn out to be nonlinear. "Our findings support the assertion that we are fundamentally destabilizing our natural systems -- we are leaving the world as we know it," says Wolfgang Lucht, one of the authors and co-chair of PIK's Research Domain of Earth System Analysis.
This is about the very basis of life
The studies use a novel methodological approach, introducing new measures of risk based on changes of vegetation structure and flows and stores of carbon and water. To this end, biosphere simulation models were used to compare hundreds of climate change scenarios and highlight which regions may first face critical impacts of climate change.
Pregnant women living in areas with contaminated drinking water may be more likely to have babies that are premature or with low birth weights (considered less than 5.5 pounds), finds a study based at Princeton University's Woodrow Wilson School of Public and International Affairs.
Featured in the Canadian Journal of Economics, the study finds the effects of contaminated water, which include numerous cognitive and developmental impairments, are particularly significant for babies born to less-educated mothers. These mothers also are less likely to uproot from areas with contaminated water, which, the researchers note, suggests a need for serious improvement in terms of communicating with people living in such environs.
"Fetuses are vulnerable to all types of pollution, including water contamination caused by chemicals and bacteria," said Janet Currie, the Henry Putnam Professor of Economics and Public Affairs at the Woodrow Wilson School of Public and International Affairs and director of the Center for Health and Wellbeing. "This contamination can lead to a host of problems, including low-birth-weight babies who can have lifelong cognitive struggles. It's a particular problem for less-educated women who also presumably have less options in terms of housing."
"We found that infants exposed to contamination in utero tend to have mothers who are younger, less educated and less likely to be married than other mothers. They are also more likely to be African-American or Hispanic," Currie said. "The results also suggest that mothers who are less educated are less likely than other mothers to move in response to contamination, while older mothers are more likely to drink bottled water or move."
While past studies have focused on the effects of air pollution on infant health, Currie's is one of the first to evaluate the effects of water pollution on infants.
Together with researchers from Columbia University and the University of California, San Diego, Currie examined ten years of New Jersey birth records and data on drinking-water quality collected from 1997 to 2007.
Using data from the New Jersey Department of Environmental Protection (DEP), Currie and her team looked at violation records across 488 water districts in New Jersey and found that more than a quarter of districts had water contamination violations affecting more than 30,000 people. These violations included both chemical and bacterial contamination caused by such contaminants as dichloroethane -- a solvent often used for plastics or as degreasers -- as well as radon and coliform.
The researchers matched the birth records to the water systems that serve the infants' residences. Because weather can dictate the amount of water a person consumes, they also incorporated daily temperatures into their dataset.
Currie notes that when a water district is affected, the DEP is required to send a notice to all residences. However, for renters, there may be routing difficulties.
"If someone puts something in your mailbox, do you even see it? Does your landlord pick it up?" said Currie. "Notices are being sent that people don't receive. There's an undercurrent here that the way information is sent isn't adequate. We need to get this information to people directly."
Currie suggests that health-care workers include literature about water contamination risks and hazards in clinics and exam rooms to reach more pregnant women.
1. Story Source:
The story is based on materials provided by Potsdam Institute for Climate Impact Research (PIK).
1. 1 Dieter Gerten, Wolfgang Lucht, Sebastian Ostberg, Jens Heinke, Martin Kowarsch, Holger Kreft, Zbigniew W Kundzewicz, Johann Rastgooy, Rachel Warren, Hans Joachim Schellnhuber. Asynchronous exposure to global warming: freshwater resources and terrestrial ecosystems. Environmental Research Letters, 2013; 8 (3): 034032 DOI: 10.1088/1748-9326/8/3/034032
1.2 S. Ostberg, W. Lucht, S. Schaphoff, D. Gerten. Critical impacts of global warming on land ecosystems. Earth System Dynamics Discussions, 2013; 4 (1): 541 DOI: 10.5194/esdd-4-541-2013
Potsdam Institute for Climate Impact Research (PIK) (2013, October 8). More than 500 million people might face increasing water scarcity. ScienceDaily. Retrieved October 9, 2013, from http://www.sciencedaily.com /releases/2013/10/131008091718.htm
2. Story Source:
The story is based on materials provided by Princeton University, Woodrow Wilson School of Public and International Affairs, via EurekAlert!, a service of AAAS.
Janet Currie, Joshua Graff Zivin, Katherine Meckel, Matthew Neidell, Wolfram Schlenker. Something in the water: contaminated drinking water and infant health. Canadian Journal of Economics/Revue canadienne d'économique, 2013; 46 (3): 791 DOI: 10.1111/caje.12039
Princeton University, Woodrow Wilson School of Public and International Affairs (2013, October 8). Something in the (expecting mother's) water: Contaminated water breeds low-weight babies, sometimes born prematurely. ScienceDaily. Retrieved October 9, 2013, from http://www.sciencedaily.com /releases/2013/10/131008122906.htm
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