Monday, March 30, 2009

World is water-stressed, lecturer says

By Katie Alvord

HOUGHTON -- A crowd of nearly 700 students and community members heard water policy expert Sandra Postel deliver Michigan Tech's second annual World Water Day lecture on Monday night, March 23, in the Rozsa Center.

Water policy expert Sandra Postel delivers a World Water Day lecture Mar. 23 in MTU's Rozsa Center. The photo in her slide, projected here, shows a treadle pump in Bangladesh. Postel, who took this photo, said the pump, costs only $35 and helps poor farmers irrigate crops to feed their families. Click on photo for larger version. (Photo © 2009 Michele Bourdieu)

Postel's speech, titled "Dividing the Waters: Strategies for a Warming, Water-Stressed World," was introduced by Civil and Environmental Engineering Professor Alex Mayer, who directs the Michigan Tech Center for Water and Society.

Postel told the audience that world water problems have increased since she began working on these issues more than 25 years ago. Formerly employed by the Worldwatch Institute, she now heads the Global Water Policy Project, based in New Mexico.

Showing a world map with broad swaths of territory marked as water-stressed, Postel cited numerous statistics demonstrating over-use of water.*

"We are using tomorrow's water to meet demands today," she said.

Extensive diversions from several major world river systems -- including the Yellow, Indus, Ganges, Colorado, Rio Grande and Australia's Murray-Darling -- now keep their waters from reaching the sea, Postel said. She added that overpumping of groundwater has caused water tables to drop in many countries, including China, India and the western United States.

Water is renewable but finite, Postel stated, pointing out that it has no substitutes. Thus, she noted, endless growth in water demand is incompatible with maintaining both aquatic ecosystems and human economic growth.

"This is the inconvenient truth about water," Postel said.

Climate change will further complicate the global water picture by altering the hydrologic cycle, bringing more intense storms and increasing drought in some areas while intensifying floods in others, she noted. Already the effects of climate change appear to be unfolding faster than expected.

"Australia is now Ground Zero for what we can expect to see with drought," Postel said, referring to the recent deadly firestorms that swept through large parts of that country, particularly the Murray-Darling river basin, after eight years of scant rainfall.

Climate change is also reducing the amount of snow and ice that provides runoff for lowland farming, Postel explained. The snowpack in California's Sierra Nevada mountain range is down, and mountain glaciers are retreating faster than expected around the world. This portends problems with food production and the potential for a significant ecological refugee problem.

Despite a current water situation that she described as "gloomy," Postel asserted that water-stress problems can be successfully addressed.

A key strategy for solving water problems, she said, is to draw a "sustainability boundary" around the amount of water needed to sustain aquatic ecosystems.

This benefits human communities as well as other species, she pointed out, since natural waters hold benefits that are critical to human survival. These benefits include water purification, groundwater recharge, flood and drought mitigation, nutrient cycling and other services provided naturally by intact aquatic ecosystems.

For instance, Postel cited one study showing that maintaining more forest cover in watersheds actually controls water treatment costs. When forest cover in the studied watershed dropped from 60 percent down to 10 percent, the area's water treatment costs tripled.

Using a sustainability boundary is not an approach that has been used in the past, Postel remarked. But, she said, quoting Albert Einstein, "'You can't solve a problem in the mindset that created the problem.'"

The sustainability boundary concept is explored more fully in the book Rivers for Life: Managing Water for People and Nature, which Postel co-authored with Brian Richter of The Nature Conservancy.

The concept is also consistent with what Postel called her water ethic: "Provide all living things with enough water before some get more than enough."

"If we have reverence for all life, it's hard to argue with this," she said.

Postel also advocated strategies that get more utility from a given amount of water, a conservation approach she called "water productivity." She cited several examples of farms, cities and industry using this approach, including the giant Unilever Corporation.

Unilever has reduced its water use by 63 percent since 1995, Postel said, and now has some zero discharge facilities which reclaim and recycle water for industrial use. The company also helps its suppliers improve their water productivity.

She noted as well that cities sometimes seek to build additional reservoirs or other water projects when they might gain just as much supply from simply plugging leaks in pipelines. One city in Japan dropped leakage from water pipelines to around 5 percent, compared to the 20 to 30 percent most municipalities lose through leakage. Such measures can save cities money by eliminating the need for new water projects.

Postel also pointed out ways that personal lifestyle choices can save water. A portion of beans takes much less water to produce than an equivalent portion of beef, for instance, suggesting significant water savings if more people eat less meat. Because animal agriculture uses so much water, a pair of leather shoes can take 8,000 liters of water to produce. Growing plant foods uses much less. One tomato, for instance, can be produced with 13 liters of water, according to Postel's statistics.

Hancock resident Gustavo Bourdieu attended Postel's lecture and seemed particularly struck by this comparison.

"My conclusion is eat tomatoes and go barefoot," Bourdieu said.

* Click here for a map showing water stress around the world.

Editor's Note: Guest author Katie Alvord is a freelance writer and author of Divorce Your Car! Ending the Love Affair with the Automobile. She was the winner of the 2007 Science Journalism Award for Online Reporting from the American Association for the Advancement of Science for her series of articles about the Great Lakes, published on Keweenaw Now.

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