Climate change today will effect the water supply for hundreds—possibly thousands—of years. Humans exist on a short leash. A person can only last around three days without drinking water. Put that way, human life is absurdly fragile; plenty of other organisms can go far longer. Just think of your houseplant. To make matters more precarious, that essential substance is growing harder to come by. You’ve heard about this: climate change and population growth is a devastating twofer.
But water scarcity doesn’t just apply to the water you can see. It isn’t just bathtub rings in Lake Mead. Of the seven and a half billion people currently residing on our fair planet, two billion rely on groundwater—water that’s seeped through the layers of soil and rock to become stored in underground deposits called aquifers. Some of this water is exceptionally old. Some of it did all its seeping when dinosaurs lumbered around. Filling some of these aquifers can take an extraordinarily long time, so on a timescale relevant to any human lifetime, much of it is not a renewable resource.
Some aquifers are closer to the surface, and can recharge more quickly. These respond fast to rainfall, for example; a good soak will replenish them. But being closer to the surface isn’t without its drawbacks. They’re more accessible to humans, so they’re already likely to be withdrawn faster than they can be filled up. And their proximity to the surface makes them more vulnerable to drought and contamination—two things on the rise amid climate change and population growth.
In a paper published this week in Nature Climate Change, scientists from the UK, Australia, Canada, Germany, France and the US used modeling and hydrological data sets to find how […]