Climate Change Is Moving Mountains - The Atlantic

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On geological 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.<br>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.<br>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.<br>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.<br>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 geological record.<br>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.<br>“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.”<br>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.<br>“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.<br>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 kinds of debris flows and mudslides now threaten more communities. In North Carolina, Hurricane Helene...