Drinking the oceans will not solve world's water problems

Posted: 19 June 2007

Making drinking water out of sea water is a growing trend but apotentially insidious threat to the environment that could alsoexacerbate climate change, says a review of desalination plants worldwide.

The review shows that some of the driest and thirstiest places are turning to desalination. These include Australia, the Middle-East, Spain, the UK and US with India and China following suit. These are all regions where water problems affect large, populous areas.

Schoolgirl drinking from rainwater tank, Nairobi
Schoolgirl drinking from rainwater tank, Nairobi
A schoolgirl in Nairobi, Kenya, drinking from a water tank that collects rain from the schoolhouse roof. Water is a threatened resource and with population growth and expanding urbanization the pressure can only increase. Photo © WWF-Canon/Martin Harvey
"Desalinating the sea is an expensive, energy-intensive and greenhouse gas emitting way to get water," says Jamie Pittock, Director of WWF's Global Freshwater Programme which carried out the review. "It may have a place in the world's future fresh water supplies but regions still have cheaper, better and complementary ways to supply water that are less risky to the environment." It is estimated that around 60 per cent of freshwater needs in the Arabian Gulf are met through desalination and Perth, Australia may be looking to source one-third of its freshwater the same way. Spain is devoting an astonishing proportion of its desalinated water to agriculture - at 22 per cent the highest level in the world - as well as to holiday resorts in arid areas.

Impacts of desalination include brine build-up, increased greenhouse gas emissions, destruction of prized coastal areas and reduced emphasis on conservation of rivers and wetlands. Many of the areas of most intensive desalination activity also have a history of damaging natural water resources, particularly groundwater.

Managing water demand and assessing impacts of any large-scale engineering solution are needed early in order to avert irreversible damage to nature and the cost overruns often paid by citizens over the long haul. Sustainable sources of water start with protecting natural assets such as rivers, floodplains, and wetlands. These natural systems purify and provide water as well as protect against extreme or catastrophic events.

Salt pans, Camargue
Salt pans, Camargue
Old salt pans on the coast of Mediterranean, Camargue, France. Photo: © WWF-Canon/Michel Gunther
"Large desalination plants might rapidly become 'the new dams' and obscure the importance of real conservation of rivers and wetlands," adds Pittock. "As with any relatively new engineering such as large dams that grew up in the 50's, the negatives become known when it is too late or too expensive to fix. What we need most is a new attitude to water not unchecked expansion of water engineering,"

To download the full report 'Making water: Desalination - option or distraction for a thirsty world?' go to wwf.org.uk