Monday, April 30, 2007

Coping with Climate Change: Australia

The Economist's description of the drought in the Murray-Darling basin (Australia's largest) provides a harbinger of how global warming will force painful accomodations:

The Murray-Darling's troubles are likely to worsen. As Australia's population continues to grow so does demand for water in the cities and for the crops that grow in the river basin. Meanwhile, global warming appears to be heating the basin up and drying it out. Although few scientists are confident that they can ascribe any individual event—including today's drought—to global warming, most agree that droughts like the present one will become more common.

Many of the world's rivers, including the Colorado in America, China's Yellow river and the Tagus, which flows through Spain and Portugal, are suffering a similar plight. As the world warms up, hundreds of millions of people will face the same ecological crisis as the residents of the Murray-Darling basin. As water levels dwindle, rows about how supplies should be used are turning farmers against city-dwellers and pitching environmentalists against politicians. Australia has a strong economy, a well-funded bureaucracy and robust political institutions. If it is struggling to respond to this crisis, imagine how drought will tear apart other, less prepared parts of the world.

Droughts have long plagued the Murray-Darling. The region is afflicted by a periodic weather pattern known as El Niño. At irregular intervals of two to seven years, the waters of the central Pacific warm up, heralding inclement weather throughout the southern hemisphere. Torrential rains flood the coast of Peru, while south-eastern Australia wilts in drought. The duration of these episodes is as unpredictable as their arrival. They can range from a few months to several years. As a result, the flow of the Darling, the longest tributary of the Murray, varies wildly, from as little as 0.04% of the long-term average to as much as 911%. Although the most recent El Niño ended earlier this year, it has left the soils in the basin so dry and the groundwater so depleted that the Murray-Darling's flow continues to fall, despite normal levels of rainfall over the past few months.

Read the whole thing to see how Australia is renegotiating all the last two centuries' social compromises about water--something that will need to happen everywhere as climate changes.

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