AS California’s economy skyrocketed during the 20th century, its land headed in the opposite direction. A booming agricultural industry in the state’s San Joaquin Valley, combined with punishing droughts, led to the over-extraction of water from aquifers. Like huge, empty water bottles, the aquifers crumpled, a phenomenon geologists call subsidence. By 1970, the land had sunk as much as 28 feet in the valley, with less-than-ideal consequences for the humans and infrastructure above the aquifers.
The San Joaquin Valley was geologically primed for collapse, but its plight is not unique. All over the world—from the Netherlands to Indonesia to Mexico City—geology is conspiring with climate change to sink the ground under humanity’s feet. More punishing droughts mean the increased draining of aquifers, and rising seas make sinking land all the more vulnerable to flooding. According to a recent study published in the journal Science, in the next two decades, 1.6 billion people could be affected by subsidence, with potential loses in the trillions of dollars.
“Subsidence has been neglected in a lot of ways because it is slow moving. You don’t recognize it until you start seeing damage,” says Michelle Sneed, a land subsidence specialist at the U.S. Geological Survey and coauthor on the paper. “The land sinking itself is not a problem. But if you’re on the coast, it’s a big problem. If you have infrastructure that crosses long areas, it’s a big problem. If you have deep wells, they’re collapsing because of subsidence. That’s a problem.”
The over exploitation of groundwater is not only very obviously unsustainable, it’s causing the land under some of the worlds biggest to sink lower and lower as the empty aquifers collapse. This is becoming a very big problem. https://t.co/wX23as1IQ7 via @wired
— Ben Goldsmith (@BenGoldsmith) January 20, 2021