On geologic timescales, the Earth is a dynamic place. Tectonic plates shift. Continents move. Mountains rise and fall. But during humanity’s tenure on Earth, the ground beneath our feet has largely stayed put.

That stable period may now be at an end. Climate change began in the atmosphere, where greenhouse gases accumulate, trapping heat from the sun. The planet’s waters reacted—precipitation patterns shifted, glaciers and ice caps began melting, the ocean generously sponged up heat and carbon dioxide.

When the Earth’s waters shift, so does solid ground. Now warming is destabilizing land across the planet, and geology is becoming a real-time science. In more and more places, the floor is giving way.

In Alaska, Norway, Greenland, Chile, and New Zealand, as well as across the European Alps, mountains are crumbling. As glaciers retreat, some at unprecedented rates, they leave behind unstable cliffs that were once supported by ice. In 2023, one collapsed into a fjord in Greenland and generated a 660-foot wave that sent ripples through the Earth detected on monitoring stations worldwide for nine days. In Alaska last year, a landslide-generated tsunami struck in a fjord frequented by cruise ships. In Switzerland the same year, part of a mountain glacier detached entirely, burying the village of Blatten in a cataclysmic landslide. In the past decade or so, scientists have collected enough dramatic examples of this phenomenon to suggest that they’re clearly not isolated incidents, but part of a pattern linking the loss of glaciers with landslide risk.

And those landslides could get larger. When the glaciers melted after the last glacial maximum, about 20,000 years ago, the landslides that followed were orders of magnitude larger than any we’ve seen in recorded history. But because some of today’s glaciers have persisted in the landscape longer than those of that glacial period did, they’ve had time to carve steep, unstable cliffs. This means that “we haven’t seen the upper bounds of landslides yet,” Kristian Svennevig, a geologist at the Geological Survey of Denmark and Greenland, told me. In Arctic regions in the near future, the magnitude of landslides could exceed any scientists know of in the geologic record.

Along with glaciers, permafrost holds mountains together at high altitudes and latitudes worldwide. It, too, is in retreat, as scientists predicted in the 1980s and as has now become apparent across the Arctic reaches. In the Brooks Range, home of the Trans-Alaska Pipeline, long-frozen mountains have started to spontaneously deform and collapse within the past few decades or so, as their permafrost glue gives way. “We’re pushing these mountains into a state of disequilibrium, where they need to adjust their slopes in order to match the climate of today,” the independent Alaskan geologist Bretwood Higman told me. They’re essentially too steep for this warmer temperature regime.

“As a geologist, I’ve found it shocking how widespread the sudden increase in landslide activity is,” Higman said. When you’re used to thinking on scales that span tens of thousands of years, to see these changes play out over human lifetimes—“it’s very dramatic.”

The thawing of permafrost in mountainous regions already threatens infrastructure. Denali National Park is close to finishing a $100 million bridge that will span a moving permafrost landslide. In the Brooks Range, engineers are pumping refrigerant underground to refreeze permafrost and stabilize pipelines. And mountains aren’t the only land giving way. Cement-solid Arctic ground is turning into bogs. Communities across Alaska have had to relocate as their homes, fuel tanks, sewage lagoons, and garbage dumps tip, spill, or sink. Elsewhere, as massive underground chunks of ancient ice melt, the surrounding earth collapses into the voids left behind, buckling roads and swallowing buildings. In Siberia, once-trapped methane explodes from under permafrost to cause 100-foot craters.

“When permafrost thaws, it changes everything,” Sue Natali, an Arctic-climate scientist at the Woodwell Climate Research Center, told me. Natali and her colleagues are seeing the thaw speed up too. “That is not a maybe thing, and it is not a local thing. It is a pan-Arctic thing,” she said.

Climate is also shifting the land at lower latitudes. A warmer atmosphere holds more moisture, which means more frequent and extreme rainfall events. In recent years, scientists have begun modeling how this kind of rain will increase landslide risk, and linking individual events to storms made more dramatic by climate change.  “Harder, more intense, longer-duration rainfall has a greater possibility to generate landslides,” Jonathan Godt, who leads the United States Geological Survey’s landslide-hazards program, told me. These kind of debris flows and mudslides now threaten more communities. In North Carolina, Hurricane Helene triggered more than 2,000 landslides in a week. In California, slopes wiped clean by logging and drought-fueled wildfires slough away after heavy rain—one mudslide in Montecito destroyed 100 homes and killed 23 people in 2018. Landslides already cause $20 billion in damage globally, and that cost will only climb with climate change.

Already, scientists have been able to catalog the effects of melting glaciers, thawing permafrost, and extreme rain. Other dramatic consequences of shifting precipitation patterns—volcanic eruptions and earthquakes—are only just coming into focus.

More than a decade ago, in his book Waking the Giant, the University College London volcanologist Bill McGuire compiled decades of paleoclimate research to predict that climate change could lead to more volcanic eruptions and earthquakes. An increase in volcanic and tectonic activity would be a natural response to the end of a glacial period. For thousands of years now, the Earth’s crust, which was weighted down by ice, has been slowly bouncing back. That process releases pressure from long-subdued faults and volcanoes, such as those in Iceland. Human-caused climate change is only accelerating these processes. And water, whether from extreme rainfall or glacial melt, can percolate in cracks underground to increase pressure on rock and reduce friction along faults, triggering both earthquakes and volcanic eruptions.

Last year, researchers in Switzerland and France found some of the clearest evidence so far that glacial melt could indeed be affecting seismic hazards in high-altitude regions. After a period of intense glacial melt in 2015, a series of small quakes struck the Grandes Jorasses on Mont Blanc Massif, on the border of France and Italy; the probability of a 3.0-magnitude earthquake rose by 10 times, Toni Kraft, a seismologist at the Swiss Seismological Service at ETH Zurich and one of the authors of a related paper, told me. These quakes are still small, but they could trigger rockfall events that are already on the rise across the Alps.

Falk Amelung, a geoscientist at the University of Miami, has also argued—somewhat controversially—that climate-driven extreme rainfall might have led to the dramatic 2018 eruption of Hawaii’s Kīlauea volcano. Scientists have not been able to find an obvious triggering mechanism for the eruption, and Amelung hypothesized that rainfall had infiltrated the volcano’s edifice and increased pore pressure in the rock, kilometers down, to the highest rates in almost 50 years. USGS volcanologists were unconvinced: A link between heavy precipitation and some types of volcanic activity is widely accepted, but some scientists still reject the theory that an eruption such as Kīlauea’s could be caused by water reaching the magma below. If Amelung and others in his camp are right, though, as many as 700 volcanoes could be at risk of dome explosions and flank collapse over the next 80 years, he calculated.

“The system must be heavily stressed in a way that it’s close to breaking anyway,” he told me. “And then this small stress change due to water brings it over the edge.”

During Earth’s long history, small perturbations have caused millennia-long swings between hothouse and icehouse conditions. The amount of carbon dioxide that we have pumped into the atmosphere, at a higher rate than ever before in Earth’s geologic history, is a pretty significant perturbation, which then causes its own significant perturbations. “The crust is not isolated. It’s always connected. The climate, the fluid layers, the solid layer—you cannot separate them,” Benedikt Soja, a geoscientist at ETH Zurich, told me. The atmosphere, ocean, and land are interacting systems, and their fragile equilibrium is reacting together to the stress we’ve put on them.