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Scientists are raising urgent concerns about the rapid melting of the Thwaites Glacier-often called the “Doomsday Glacier”-warning that its potential collapse could have dire consequences for global sea levels.
Located on the West Antarctic Ice Sheet, the Thwaites Glacier covers an area larger than the state of Florida and is among the fastest retreating glaciers in Antarctica. Spanning roughly 80 miles wide, it is recognized as the world’s broadest glacier.
Researchers have dubbed it the “Doomsday Glacier” because of its alarming rate of deterioration, driven largely by warming ocean waters linked to climate change. If the glacier were to fully collapse, scientists warn it could raise sea levels by nearly 11 feet, putting many major coastal cities worldwide at significant risk.
Currently, the glacier contributes about 4% of the global sea-level rise, losing approximately 50 billion tons more ice each year than it gains through snowfall, according to the International Thwaites Glacier Collaboration.
A 2024 study from the University of California, Irvine, and the University of Waterloo used high-resolution satellite radar to identify areas where warm seawater is infiltrating beneath the glacier’s grounded ice, accelerating melt and increasing sea-level rise. Christine Dow, an associate professor of glaciology at the University of Waterloo and co-author of the study, highlighted the instability of Thwaites, noting it holds the equivalent of 60 centimeters of potential sea-level rise.
Dow emphasized the uncertainty surrounding how quickly these changes might become irreversible and stressed the need for improved models to better predict timelines-whether decades or centuries-and to aid in adaptation efforts while also underscoring the importance of reducing carbon emissions to avoid worst-case outcomes.
In contrast, another 2024 study published in Science Advances by researchers from Dartmouth College and the University of Edinburgh suggests the glacier may be less vulnerable to marine ice cliff instability than previously thought. Their simulations indicate that the glacier might not retreat further within this century, with thinning potentially reducing ice calving and helping to stabilize the ice cliffs. The authors call for a re-examination of existing model projections based on these findings.
The potential impact of rising sea levels is starkly illustrated by a National Oceanic and Atmospheric Administration (NOAA) map projecting a 10-foot sea-level increase. Such a rise would subject vast portions of the U.S. coastline to catastrophic flooding, submerging entire communities.
Florida would be among the hardest hit, with cities like Jacksonville, Fort Lauderdale, Tampa, St. Petersburg, and Panama City at serious risk. Coastal areas in Texas-including Galveston Bay, Freeport, and Surfside Beach-and parts of Louisiana near New Orleans would also face significant threats.
Other vulnerable cities include Charleston, South Carolina; Savannah, Georgia; Norfolk and Virginia Beach, Virginia; Wilmington, North Carolina; Baltimore, Maryland; New York City; and regions of New Jersey, Delaware, and Mississippi. California’s coastal areas such as San Francisco Bay, Oakland, San Mateo, San Diego, and Santa Barbara are also projected to experience substantial flooding.
The evolving science around Thwaites Glacier underscores the urgency of addressing climate change and preparing for the profound challenges that rising sea levels will pose to communities worldwide.