Water, Hold the Salt

Climate change doesn’t impact all areas of the world in the same way. But, water plays a key role in many of the effects of climate change, whether through its severe absence or its overabundance. As South Korea was hit this week with its worst typhoon in ten years and Hurricane Isaac struck New Orleans, much of the United States is still facing its worst drought in 50 years.

Extreme weather events like the above are interlinked with climate change, according to the U.N. Framework Convention for Climate Change (UNFCCC). While specific events may not be caused by climate change, per se, climate change does affect the frequency and intensity of such events by disrupting the Earth’s climate system.

As a result of certain severe weather events, water shortages around the world are becoming more pronounced. In the U.S. alone, the drought has caused lower crop yields and, subsequently, higher food prices and lower ethanol production. We depend upon water for drinking, food production, household use, and now fracking (which requires millions of gallons of water to release natural gas from veins deep underground). So, what are we to do when our water supply comes up short?

More frequently, we are now turning to desalination (the process of removing salt from water to produce freshwater) as a solution. While the process itself dates back to ancient times, desalination was not performed on an industrial scale in the U.S. until after World War II. It is now growing rapidly; according to Global Water Intelligence, the desalination industry is expected to nearly double from $8.9 billion today to $17 billion in 2016.

Cost has always been one of the major limitations to large-scale desalination, as it is an energy-intensive process. Today, the reverse osmosis desalination method used (where salt water is run through a series of semi-permeable membranes to separate out the salt) costs ten times more than traditional water sources per cubic meter, even though this cost has been halved since the method was introduced. However, a forward osmosis method (a process combining membrane and thermal/evaporative purification) is being developed that should require less heat and energy and could cost 30% less.

Water demand is only expected to rise as global population increases. Because the availability of freshwater is so limited, I think that desalination of ocean water will become essential. Industrial desalination will be particularly important because it allows for the achievement of economies of scale. If desalination systems could be linked with municipal water distribution systems, regional fresh water supplies could be supplemented with ocean water in coastal areas. Surplus supplies could also be shipped to areas experiencing drought and water shortages. Even though desalination is costly now, costs will almost certainly decrease as research and development resources are focused upon the industry. Considering our current water woes, desalination technology is an investment we can’t afford to pass up.

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