An international team led by the University of Portsmouth has cataloged more than 3,100 surging glaciers worldwide that can suddenly accelerate, triggering floods, avalanches and other hazards. These glaciers, concentrated in regions like the Arctic and Karakoram Mountains, affect nearly one-fifth of global glacier area despite comprising just 1 percent of all glaciers. Climate change is altering their behavior, increasing unpredictability.
Glaciers typically shrink amid rising temperatures, but surging glaciers behave differently. They periodically speed up dramatically, pushing large volumes of ice forward over years-long cycles. A study published in Nature Reviews Earth and Environment analyzed data on these 3,100 glaciers, finding clusters in the Arctic, High Mountain Asia and the Andes. Dr. Harold Lovell, a glaciologist at the University of Portsmouth, described them as saving ice like a bank account before spending it rapidly, potentially causing catastrophic disasters for thousands of people near them. The research identified six key hazards: glacier advances over infrastructure, river blockages forming unstable lakes, meltwater outbursts, ice and rock avalanches, dangerous crevasses and ocean iceberg releases endangering shipping. Among them, 81 glaciers pose the greatest threats, particularly in the Karakoram Mountains where communities and infrastructure lie downstream. Warming temperatures exacerbate risks by triggering surges through extreme rain or heat, with patterns shifting regionally—more frequent in some Arctic areas, less so in Iceland. Co-author Professor Gwenn Flowers of Simon Fraser University noted that climate change is rewriting surge mechanisms just as understanding improves, complicating community protection. The scientists call for enhanced satellite monitoring, field observations and modeling to forecast surges amid ongoing warming.