Photograph courtesy Organization for Rehabilitation and Development of Amhara
Published September 7, 2010
This post is part of a special National Geographic news series on global water issues.
As we’ve seen with severe droughts in Pakistan followed just months later by debilitating floods, the climate change impacts scientists have warned us about for years may finally be here, making the weather harder to predict and prepare for, and traditional sources of irrigation water much less reliable.
These changes have dire consequences for feeding an ever-expanding global population, especially in areas of Africa and Asia where millions of farmers rely solely on rainwater for their crops, according to the Sri Lanka-based International Water Management Institute (IWMI), which issued the report.
In Asia, 66 percent of cropland is rain-fed, while 94 percent of farmland in sub-Saharan Africa relies on rain alone, according to IWMI. These are the regions where water storage infrastructure is least developed and where nearly 500 million people are at risk of dire food shortages, the report cautions.
In sub-Saharan Africa, existing water storage is equal to less than 26,400 gallons (100 cubic meters) per person, compared to 1.3 million gallons (5,000 cubic meters)—enough to fill two Olympic-size swimming pools—in the U.S., according to Colin Chartres, director general of IWMI.
“Climate change will hit these people [in Africa and Asia] hard, so we have to invest heavily and quickly in adaptation,” said Chartres in a statement. “We’ve missed the boat on climate change mitigation,” he told National Geographic News.
Diversify and Insure
How can these regions adapt? Fund a diversity of water storage projects—from small-scale rainwater tanks and larger-scale dams, to systems that artificially recharge groundwater aquifers, to improving the soil so it can hold more water.
The solution, at least a large part of it, is to “use stored water as insurance against climate change and climate variability,” according to Chartres. “If we can we capture some of these big events, like what is happening now in Pakistan, we can channel it back into wells, and old irrigation reservoirs and tanks.”
Stored water in times of drought can “make all the difference between chronic hunger and steady progress toward food security,” Matthew McCartney, the report’s lead author and a hydrologist at IWMI, said in a statement.
“Just as modern consumers diversify their financial holdings to reduce risk, smallholder farmers need a wide array of ‘water accounts’ to provide a buffer against climate change impacts,” he added.
Small-scale efforts have delivered some positive results, when well planned with the participation of both politicians and farmers, according to IWMI.
The nonprofit points to Zimbabwe, where small collection basins have boosted maize yields in times of rain or drought. In India’s Rajasthan State, 10,000 water harvesting structures that help to recharge groundwater now irrigate 34,600 acres (14,000 hectares) and feed 70,000 people.
Chartres adds that decision-makers in India, where there is expected to be a 50 percent gap between water demand and supply by 2030, are starting to fund storage projects, because they realize the long-term economic benefits of a secure supply.
While the early results seem positive, some experts argue that decision-makers have to diversify even beyond storage.
“Storing water is not an end in itself,” said Sandra Postel, director of the Global Water Policy Project and National Geographic’s freshwater fellow, via e-mail. “It is a means to meet food, energy, and drinking water needs. The key goal of climate adaptation should be to build resilient ways of meeting these needs in an equitable and environmentally sound fashion.” A more holistic approach includes conservation and efficiency improvements, Postel explained.
The need to feed and provide electricity for growing populations has brought about a resurgence in big dam building.
Despite controversy over these projects, which have been associated with significant environmental damage, the displacement of tens of millions of people, and the loss of an income for hundreds of millions of fishers and farmers downstream, Chartres says they are an inevitable part of the picture.
“We’re not going to stop dams with the demand for energy. It’s green energy. We should be asking how to make them more sustainable.”
IWMI recommends that dam builders more carefully weigh the social and environmental consequences against the economic benefits.
Postel agrees with IMWI that large dams are one of many viable solutions, but she cautions that when planning for larger-scale projects in the face of climate change, planners have to take a landscape or watershed approach to storing and managing water. “We are going into a period with greater uncertainty and variability—so you want to build in resilience. If you construct dams of any size, you want to invest in watershed protection, for example.”
A well-forested riverbank or thriving wetland can slow floodwaters, reduce erosion, and protect dams from becoming clogged with silt—a problem that reduces dam capacity and value.
(Read an interview with Chartres about his new book Out of Water: From Abundance to Scarcity and How to Solve the World's Water Problems and Postel’s 2010 essay about finding hope, even in the bleak landscape of the Aral Sea Basin.)
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