Alaska's top-heavy glaciers are approaching an irreversible tipping point

Alaska's Juneau Icefield, one of North America's largest icefields, is experiencing accelerated melting, potentially reaching an irreversible tipping point. Research indicates that rising temperatures are causing less snow to remain through the summer, leading to increased ice exposure to sunlight and higher temperatures, accelerating the melting process. The top-heavy glaciers in Alaska, including those in the Juneau Icefield, are particularly vulnerable as the end-of-summer snowline rises, exposing more ice to melting. Satellite data reveals a significant increase in glacier shrinkage since 1979, with glaciers melting five times faster between 2015 and 2019 compared to 1979-1990. The darkening of the icefield due to decreased snow reflects less solar energy, exacerbating the melting. This ongoing trend could lead to a self-perpetuating loss of snow and ice, even if global warming were to cease. Understanding these feedback mechanisms is crucial for predicting future glacier behavior and the implications for the region's stability.