By Andrew Maddocks, Betsy Otto, & Tianyi Luo
When it comes to water, there is often too little or too much. Climate change and growing demand will likely magnify those extremes.
While there is no way to predict exactly what the world’s water resources will look like in the future, the World Resources Institute has mapped future water-risk scenarios based on the International Panel on Climate Change’s projections for climate change and socioeconomic development. This glimpse of the future is designed to help governments, businesses, financial institutions, and other international organizations take steps to mitigate risk.
Water stress — the measure of demand relative to supply in a given place — will likely increase rapidly across the globe in the next few decades, as more people compete for ever more limited surface-water supplies.
When people think about water stress, they often think of major changes in supplies — years-long droughts, or dry monsoon seasons. Such events will play a significant part, and their consequences will be severe. What we’ve found, though, is that rapidly growing demand for water actually drives the greatest increases in water stress.
Major climate-driven shortages in water supply, where they do occur, will be concentrated around mid-latitude regions. These lie between the equator and the 30-degree north and south latitude lines, and extend to North Africa, southern Texas, and China in the Northern Hemisphere, and northern Chile, Argentina, and South Africa in the Southern Hemisphere.
Many variables affect precipitation patterns, and decision-makers must plan for a wide range of possible outcomes. Both a 30 percent increase and a 30 percent decrease in surface-water supply within the next three decades, for example, are in the realm of possibility in areas including Southern California, according to climate models. The only sure thing is more extremes, and more unpredictability.
Picture: Liam M. Higgins [Copyrighted free use], via Wikimedia Commons