A new study, Four billion people facing severe water scarcity, finds that freshwater scarcity constitutes "a global systemic risk," and that previous studies seriously underestimated water scarcity. The report's conclusion is worth reprinting here.
Meeting humanity’s increasing demand for freshwater and protecting ecosystems at the same time, thus maintaining blue water footprints within maximum sustainable levels per catchment, will be one of the most difficult and important challenges of this century...Proper water scarcity assessment, at the necessary detail, will facilitate governments, companies, and investors to develop adequate response strategies. Water productivities in crop production will need to be increased by increasing yields and reducing nonproductive evaporation...An important part of a strategy to reduce the pressure on limited blue water resources will be to raise productivity in rain-fed agriculture...It will be important that governments and companies formulate water footprint benchmarks based on best available technology and practice...Assessing the sustainability of the water footprint along the supply chain of products and disclosing relevant information will become increasingly important for investors...
That last point in particular indirectly drives home the urgency of switching from fossil fuels to a clean energy economy. As we noted recently, fossil fuel power plants use large volumes of increasingly scarce water resources, while clean energy sources like solar PV and wind use minimal amounts or none at all. As the Union of Concerned Scientists explains, “[a] typical coal plant with a once-through cooling system withdraws between 70 and 180 billion gallons of water per year and consumes 0.36 to 1.1 billion gallons of that water.” Also see the 2011 report, “Freshwater Use by U.S. Power Plants: Electricity’s Thirst for a Precious Resource,”which found that power plants in the U.S. use nearly three times as much water every minute as flows over Niagara Falls.
It's not just power plants, either; as Scientific American reported last July, citing a study by the U.S. Geological Survey, "Oil and natural gas fracking, on average, uses more than 28 times the water it did 15 years ago, gulping up to 9.6 million gallons of water per well and putting farming and drinking sources at risk in arid states, especially during drought." Also consider that oil refining is a water-intensive process: "Refineries use about 1 to 2.5 gallons of water for every gallon of product, meaning that the United States, which refines nearly 800 million gallons of petroleum products per day, consumes about 1 to 2 billion gallons of water each day to produce fuel." Finally, fossil fuel operations frequently contaminate - or threaten to contaminate - freshwater sources. For instance, fracking poses a serious potential risk to aquifers, as do the oil pipelines such as Keystone XL.
Again, all of these problems essentially disappear, simply by switching from fossil fuels to a clean energy economy. The good news is that making this switch makes sense from a purely economic perspective, in addition to solving numerous environmental problems, including the world's severe water scarcity crisis. That's a "win-win" situation no matter how you look at it.