Most glaciers around the world are shrinking as temperatures rise. But a smaller group behaves in a very different way, and their actions can be far more dangerous. An international team of scientists led by the University of Portsmouth has completed a large global study of these so-called surging glaciers. The research looks at the risks they pose and how climate change is reshaping when and where these sudden events occur. What Causes Glacier Surges A glacier surge happens when ice that normally moves slowly suddenly speeds up. During these periods, large amounts of ice are pushed quickly toward the glacier's front, often causing it to advance. These surges can last for several years, and many glaciers go through repeated cycles, with long quiet periods in between. The study, published in Nature Reviews Earth and Environment , brought together data on more than 3,100 glaciers that have experienced surges.…