OCEAN DESALINATION - By mid-century, four billion of us will face severe fresh water shortages. Freshwater scarcity is already posing major problems for more than a billion people around the world. Desalination - a process whereby highly pressurized ocean water is pushed through tiny membrane filters and distilled into drinking water -- is being held forth by some as one of the most promising solutions to the problem. But critics point out it doesn't come without its economic and environmental costs. Ocean water is the most expensive form of fresh water out there. In the U.S., desalinated water costs at least five times as much to harvest as other sources of fresh water. Similar high costs are a big hurdle to desalination efforts in poor countries as well, where limited funds are already stretched too thin. Widespread desalination could take a heavy toll on ocean biodiversity. Ocean water is filled with living creatures, and most of them are lost in the process of desalination. Most are microbial, but intake pipes to desalination plants also take up the larvae of a cross-section of life in the sea, as well as some fairly large organisms. The very salty residue leftover from desalination must be disposed of properly, not just dumped back into the sea. Coastal areas already battered by urban and agricultural run-off can ill afford to absorb tons of concentrated saltwater sludge.

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Ocean Desalination

Can Ocean Desalination Solve the World's Water Shortage?

By Earth Talk

  

Freshwater scarcity is already posing major problems for more than a billion people around the world, mostly in arid developing countries.

The World Health Organization predicts that by mid-century, four billion of us -- nearly two-thirds of the world’s present population -- will face severe fresh water shortages.

Population Growth Drives Quest for Water by Desalination

With the human population expected to balloon another 50 percent by 2050, resource managers are increasingly looking to alternative scenarios for quenching the world's growing thirst. 

Desalination -- a process whereby highly pressurized ocean water is pushed through tiny membrane filters and distilled into drinking water -- is being held forth by some as one of the most promising solutions to the problem.

But critics point out it doesn't come without its economic and environmental costs.

Costs and Environmental Impact of Desalination

According to the non-profit Food & Water Watch, desalinated ocean water is the most expensive form of fresh water out there, given the infrastructure costs of collecting, distilling and distributing it.

The group reports that, in the U.S., desalinated water costs at least five times as much to harvest as other sources of fresh water.

Similar high costs are a big hurdle to desalination efforts in poor countries as well, where limited funds are already stretched too thin.

On the environmental front, widespread desalination could take a heavy toll on ocean biodiversity.

"Ocean water is filled with living creatures, and most of them are lost in the process of desalination," says Sylvia Earle, one of the world's foremost marine biologists and a National Geographic Explorer-in-Residence.

“Most are microbial, but intake pipes to desalination plants also take up the larvae of a cross-section of life in the sea, as well as some fairly large organisms… part of the hidden cost of doing business,” she says.

Earle also points out that the very salty residue leftover from desalination must be disposed of properly, not just dumped back into the sea.

Food & Water Watch concurs, warning that coastal areas already battered by urban and agricultural run-off can ill afford to absorb tons of concentrated saltwater sludge.

Is Desalination the Best Option?

Food & Water Watch advocates instead for better freshwater management practices.

"Ocean desalination hides the growing water supply problem instead of focusing on water management and lowering water usage," the group reports, citing a recent study which found that California can meet its water needs for the next 30 years by implementing cost-effective urban water conservation.

Desalination is "an expensive, speculative supply option that will drain resources away from more practical solutions," the group says.

Of course, the recent California drought sent everyone back to their drawing boards, and the appeal of desalination has revived.

A plant providing water for 110,000 customers opened in December 2015 in Carlsbad, north of San Diego, at a reported cost of $1 billion.

The practice of desalinating salt water is becoming more common worldwide.

Ted Levin of the Natural Resources Defense Council says that more than 12,000 desalination plants already supply fresh water in 120 nations, mostly in the Middle East and the Caribbean.

And analysts expect the worldwide market for desalinated water to grow significantly over the coming decades.

Environmental advocates may just have to settle for pushing to "green" the practice as much as possible in lieu of eliminating it altogether.

Edited by Frederic Beaudry.

Professor of Environmental Science

Education

Ph.D., Wildlife Ecology, University of Maine

M.A., Natural Resources, Humboldt State University

B.S., Biology, Université du Québec à Rimouski

Introduction

Associate professor of environmental science, Alfred University 

Academic publication credits include Biological Conservation and Journal of Applied Ecology 

Experience

Frederic Beaudry, Ph.D., is a former writer for ThoughtCo who contributed articles on pollution, global warming, and climate science for three years. He is an associate professor of environmental science at Alfred University in New York. 

Prior to teaching, Dr. Beaudry worked as a wildlife biologist, focusing on the ecology and conservation of birds and turtles. He has authored several scientific papers on land use and conservation and has conducted research examining land use changes and their effects on bird and amphibian communities. Dr. Beaudry's work can be found in peer-reviewed journals such as Biological Conservation, Journal of Applied Ecology, and the Journal of Wildlife Management. 

Education

Dr. Beaudry has a B.S. in biology from Université du Québec à Rimouski and an M.A. in natural resources from Humboldt State University. He earned a Ph.D. in wildlife ecology at the University of Maine. He also completed postdoctoral research at the University of Wisconsin-Madison.

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https://www.thoughtco.com/ocean-desalination-to-solve-the-water-shortage-1203579