Most mountain glaciers outside of the polar regions are currently losing ice mass. However, glaciologists identified a significant exception in the Karakoram Range—a mountainous region spanning the borders of Pakistan, India, Afghanistan, Tajikistan, and China. Since the late 1990s, glaciers in this region have experienced modest gains rather than the retreats seen elsewhere in High Mountain Asia. This phenomenon, dubbed the "Karakoram Anomaly," has become a focal point for researchers studying how different geographical and meteorological factors influence glacial health.
One primary explanation for the anomaly involves the unique weather patterns of the region. Unlike much of the Indian subcontinent, which receives moisture from various sources, the Karakoram receives a significant portion of its precipitation as wintertime snowfall carried by westerly winds from the Mediterranean and Caspian Sea regions. A 2020 review paper concluded that these westerly winds likely increased snowfall, providing a buffer against the mass loss observed in neighboring regions. Furthermore, a 2022 study found that while the frequency of these weather events remained steady, the intensity of wintertime precipitation in the Karakoram rose by roughly 10 percent after the start of the 21st century.
This diagram explains the specific regional weather patterns and precipitation sources that contribute to the anomaly.
Despite these historical gains, the long-term stability of the Karakoram glaciers remains uncertain. Scientists are currently debating whether the anomaly is a permanent feature or a temporary reprieve from global warming. For instance, a 2023 study suggested that the increasing trend of glacier mass observed between 1990 and 2010 has begun to decrease since the 2010s, potentially indicating a weakening of the anomaly due to continuous warming. Researchers also point to examples like Norwegian glaciers, which showed gains in the 1990s before turning sharply negative in the 2000s, as a possible preview of what might happen in the Karakoram as temperatures continue to rise.
This chart illustrates the historical trend of Norwegian glaciers mentioned as a possible preview of future Karakoram trends.