Economist : Water shortages a growing problem

From the Economist via LN Publisher – April 9, 2009

Water shortages are a growing problem, but not for the reasons most people think

THE overthrow of Madagascar’s president in mid-March was partly caused by water problems—in South Korea. Worried by the difficulties of increasing food supplies in its water-stressed homeland, Daewoo, a South Korean conglomerate, signed a deal to lease no less than half Madagascar’s arable land to grow grain for South Koreans. Widespread anger at the terms of the deal (the island’s people would have received practically nothing) contributed to the president’s unpopularity. One of the new leader’s first acts was to scrap the agreement.

Three weeks before that, on the other side of the world, Governor Arnold Schwarzenegger of California declared a state of emergency. Not for the first time, he threatened water rationing in the state. “It is clear,” says a recent report by the United Nations World Water Assessment Programme, “that urgent action is needed if we are to avoid a global water crisis.”

Local water shortages are multiplying. Australia has suffered a decade-long drought. Brazil and South Africa, which depend on hydroelectric power, have suffered repeated brownouts because there is not enough water to drive the turbines properly. So much has been pumped out of the rivers that feed the Aral Sea in Central Asia that it collapsed in the 1980s and has barely begun to recover.

Two global trends have added to the pressure on water. Both are likely to accelerate over coming decades.

The first is demography. Over the past 50 years, as the world’s population rose from 3 billion to 6.5 billion, water use roughly trebled. On current estimates, the population is likely to rise by a further 2 billion by 2025 and by 3 billion by 2050. Demand for water will rise accordingly.

Or rather, by more. Possibly a lot more. It is not the absolute number of people that makes the biggest difference to water use but changing habits and diet. Diet matters more than any single factor because agriculture is the modern Agasthya, the mythical Indian giant who drank the seas dry. Farmers use about three-quarters of the world’s water; industry uses less than a fifth and domestic or municipal use accounts for a mere tenth.

The other long-term trend affecting water is climate change. There is growing evidence that global warming is speeding up the hydrologic cycle–that is, the rate at which water evaporates and falls again as rain or snow. This higher rate seems to make wet regions more sodden, and arid ones drier. It brings longer droughts between more intense periods of rain.

Climate change has three big implications for water use. First, it changes the way plants grow. Trees, for example, react to downpours with a spurt of growth. During the longer droughts that follow, the extra biomass then dries up so that if lightning strikes, forests burn more spectacularly. Similarly crops grow too fast, then wilt.

Second, climate change increases problems of water management. Larger floods overwhelm existing controls. Reservoirs do not store enough to get people or plants through longer droughts. In addition, global warming melts glaciers and causes snow to fall as rain. Since snow and ice are natural regulators, storing water in winter and releasing it in summer, countries are swinging more violently between flood and drought. That is one big reason why dams, once a dirty word in development, have been making a comeback, especially in African countries with plenty of water but no storage capacity. The number of large dams (more than 15 metres high) has been increasing and the order books of dam builders are bulging.

Third, climate change has persuaded western governments to subsidise biofuels, which could prove as big a disaster for water as they already have been for food. At the moment, about 2% of irrigated water is used to grow crops for energy, or 44km3. But if all the national plans and policies to increase biofuels were to be implemented, reckons the UN, they would require an extra 180km3 of water. Though small compared with the increase required to feed the additional 2 billion people, the biofuels’ premium is still substantial.

The world might also be better off, at least in terms of water, if trade patterns more closely reflected the amount of water embedded in traded goods (a concept called “virtual water” invented by Tony Allan of King’s College London). Some benign effects happen already: Mexico imports cereals from America which use 7 billion cubic metres (m{+3}) of water. If it grew these cereals itself, it would use 16 billion m{+3}, so trade “saves” 9 billion m{+3} of water. But such beneficial exchanges occur more by chance than design. Because most water use is not measured, let alone priced, trade rarely reflects water scarcities.

Water is rarely priced in ways that reflect supply and demand. Usually, water pricing simply means that city dwellers pay for the cost of the pipes that transport it and the sewerage plants that clean it.

Basic information about who uses how much water is lacking. Rainwater and river flows can be measured with some accuracy. But the amount pumped out of lakes is a matter of guesswork and information on how much is taken from underground aquifers is almost completely lacking.

As is often the way, business is ahead of governments in getting to grips with waste. Big drinks companies such as Coca Cola have set themselves targets to reduce the amount of water they use in making their products (in Coke’s case, by 20% by 2012). The Nature Conservancy, an ecologically-minded NGO, is working on a certification plan which aims to give companies and businesses seals of approval (a bit like the Fairtrade symbol) according to how efficiently they use water. The plan is supposed to get going in 2010. That sort of thing is a good start, but just one step in a long process that has barely begun.

… Read the entire article

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