Snowpack, the frozen reservoir of sorts that flows from mountain ranges into waterways during warmer months as snowmelt, is a lifeline. Without it, entire rivers can cease to exist, farmland can grow arid, and aquifers can run dangerously low. In the United States alone, snowmelt supplies 75 percent of the American West’s entire water supply. Within the next century, however, snowpacks around the world could become but a distant memory.
According to a new study from Columbia University’s Earth Institute, snow-dependent drainage basins that supply much of the world with water are steadily declining. Regions throughout the western U.S., southern Europe, the Middle East, and Central Asia, could experience a 67 percent risk of decreased snow supply within the next 100 years.
Of the nearly 400 drainage basins examined in the study, researchers pinpointed 32 from which some 1.45 billion people depend on snowmelt, including the Colorado and Rio Grande Rivers, and the Shatt al Arab basin, which supplies parts of Iraq, Syria, eastern Turkey, Saudi Arabia, and Iran with water. Some of the most vulnerable areas to warming temperatures include parts of the Mediterranean and the Iberian Peninsula, which have a 100 percent risk of losing their snowpack as a pivotal water source, according to the study.
In all likelihood, snowpack declines within the next 100 years could be much more severe than predicted, as the study does not take population growth—and therefore increased water demand—into account. For survival, regions with less snowmelt will face serious infrastructure adjustments, like water recycling or pumping groundwater. In California, which is currently facing its lowest snowpack in 500 years, the state’s ongoing and stringent water rations are a testament to its reliance on a steady, robust snowpack each year. And as California’s sinking landscape—a result of over-pumping groundwater supplies—illustrates, these compromises do not come without inherent challenges of their own.
“Our estimate of snow resource potential provides a meaningful baseline for quantifying the risk that different regions face from changes in climate,” the authors write. “These basins are particularly critical, as emerging increases in unmet demand must be supplied by alternative sources, in many cases within the context of decreasing snow resource potential.”
And a sobering baseline at that.
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