The Risks of Turning Saltwater into Drinking Water

A growing demand to turn seawater into drinking water around the world could have serious and unintended consequences for the environment if not pursued responsibly, according to a new report from WWF.

In "Making Water: Desalination -- Option or Distraction for a Thirsty World?" WWF warns that the increasing number of desalination projects around the globe could threaten sensitive coastal areas, damage groundwater supplies, worsen global warming and reduce public interest in conserving rivers and wetlands.

"As with any relatively new engineering such as large dams that grew up in the '50s, the negatives become known when it is too late or too expensive to fix," said Jamie Pittock, director of WWF's Global Freshwater Programme. "What we need most is a new attitude to water not unchecked expansion of water engineering."

Countries in the Arabian Gulf already meet about 60 percent of their freshwater needs through desalination plants that remove salt from seawater. Many other countries around the world -- including Australia, the U.S., the U.K., Spain, India and China -- are increasingly looking to such technology to meet the needs of large cities in dry or drying climates. Faced with growing drought and depleting aquifers, for example, Perth in Australia is hoping to obtain one-third of its freshwater via desalination. And Spain is already using a large quantity of desalinated water for farming.

Such solutions, however, do not provide the benefits of natural water sources, WWF said. Rivers, floodplains and wetlands not only provide water but purify water and provide protection against extreme weather events.

Desalination, on the other hand, consumes large quantities of energy, which could aggravate the trends already causing global warming. Poorly designed plants also pose a risk to young fish and other small sea organisms that can be drawn up into inlet pipes, and can alter natural coastal systems with warm or brine-heavy outputs, according to WWF.

The report also raised questions about the ethics of generating desalinated water for well-off countries while many developed nations lack even the bare minimum access to clean drinking water or sanitation facilities. It points to the "virtual water" costs of products such as cotton T-shirts, which can require 4,100 liters of water to produce. Australia's premier Bob Carr once echoed such concerns by calling desalinated water "bottled electricity" that requires substantial amounts of coal-fired power to generate, resulting in ever more greenhouse gases.

While the number of desalination plants is growing, those statistics include many operations that have been built but never operated or been operated and then shut down, WWF said. Over half the plants considered "operational" in the U.S., for instance, are not currently on line. In one case in Tampa, a $110 million plant set to open in 2002 was later closed for $48 million in repairs in 2005 before reopening again this past April.

"To put it in context it should be noted that the energy intensity of water in most nations is both significant and increasing as water is sourced from deeper or further away," the report stated. "More marginal water in many areas has meant increases in water treatment costs ... Energy production is also a water intensive process ... (U)nanticipated water shortages around the world in recent years have reduced or threatened power generation from hydro, nuclear and coal powered generating facilities. Many jurisdictions are now anxious over the long term impacts on power generating capabilities of long-term changes in water availability from the degradation of water sources or climate change. In other words, energy and water issues need to be considered together."

WWF, "Desalination: Option or Distraction for a Thirsty World?" URL: (http://www.panda.org/news_facts/newsroom/index.cfm?uNewsID=106660)