Picture waking up in a city that’s sinking silently, almost imperceptibly, into the ground beneath your feet. It may sound like the script for a disaster film, but for over 34 million Americans nationwide, it’s just another day. Land subsidence in cities—the gradual, continuous sinking of the earth—is no longer an ocean problem. It’s occurring in cities inland as well. The earth under our feet is moving, and most of us don’t know it.
Recent satellite imagery tells a sobering tale: all 28 of the nation’s largest cities are experiencing some degree of land subsidence. In the majority of them, more than two-thirds of the surface is subsiding. Leonard Ohenhen, postdoctoral researcher at Columbia Climate School, puts it bluntly: “With time, this subsidence will create stresses on infrastructure that will exceed their safety threshold.” Houston takes the top spot, with more than 40% of its territory subsiding over 5 millimeters annually. Certain areas are falling five centimeters per year. Dallas, Fort Worth, New York, Las Vegas, San Diego—they’re among those places quietly falling.
So what’s pushing our cities down slowly? The largest culprit is groundwater pumping. As cities expand and water demand grows, we extract more and more from underground aquifers quicker than nature can recharge them. That creates empty voids in the ground that cave in under pressure, dragging the surface down with them. Scientists estimate that roughly 80% of this subsidence results from groundwater pumping. In Texas, the issue is worsened by drilling for oil and gas, which puts still more stress on the land.
But it’s not only what we’re bringing out of the ground—it’s also what we’re adding on top. The mass of millions of buildings, particularly in urban areas such as New York, is pushing the ground down. Natural processes play a role, too. Some regions are still recovering from the melting of gigantic ice sheets in the last Ice Age, and that slow-motion rebound is reshaping the ground beneath our feet.
Why does this issue matter? Because subsidence isn’t just sinking the ground—it is weakening the very foundations of our existence. Roads break. Bridges collapse. Buildings tilt. You might not even notice anything until something fails or floods. Sinking land, added to rising sea levels, increases the potential for flooding hugely. Eight major American cities have had more than 90 major floods since 2000, likely exacerbated by sinking land.
And it’s not uniformly distributed. Certain areas of a city settle more quickly than others, and that causes what experts term “differential motion.” That can result in buildings tilting, pipes cracking, and roads curving unevenly. In San Antonio alone, for example, one in every 45 buildings is in danger from uneven settling. The situation is usually worse in city centers, where thousands of residents and workers live and work over unstable ground.
This is not solely America’s problem. Cities all over the world—Jakarta, Venice, Manila—are contending with the same issue, sinking even more rapidly in many instances. Several nations are even contemplating relocating their capital cities to higher ground.
What can we do, then? The silver lining is that subsidence occurs slowly. That provides us some time to react if we take action immediately. Step one is more monitoring. Satellite imagery and land-based sensors can be used to monitor sinking in real time. Smarter water management is needed—refilling aquifers, recycling water, and alternatives to groundwater use, for example. Urban areas can also resort to green solutions, such as artificial wetlands, to assist in absorbing floodwaters and elevating land levels.
All of this requires collaboration. Public-private partnerships among governments, businesses, and neighborhoods are crucial to implementing solutions. Education is equally essential. The majority of citizens don’t know their city is sinking until it’s too late. Educating the public and encouraging sustainable water practices can make a difference.