Arctic Glacier Mass Balance
1. This indicator shows the cumulative change in mass balance, or the net gain or loss of snow and ice (accumulation vs. melting and sublimation), since 1945 of eight routinely-measured glaciers located north of the Arctic Circle. The measurements are in meters of water equivalent, which is equivalent to the mass loss of the glacier, and representative of changes in the average thickness of a glacier. Cumulative change is determined from the base year of 1970, the first year in which all eight glaciers had annual mass balance data.
2. Since 1945, the eight Arctic glaciers have experienced a decline in mass balance overall. One exception to this pattern is Engabreen, near the subpolar zone along the coast of Norway, which gained mass over the period of record. This trend is anomalous and does not reflect the significant global loss of land ice as measured and catalogued from numerous glaciers elsewhere in the Arctic and around the world in the 20th century. Engabreen is more strongly influenced by precipitation than glaciers elsewhere in the Arctic.
3. The loss of land-based ice in the Arctic has accelerated in recent decades, contributing to sea level rise. Glaciers are important as an indicator of climate change as they provide visible, enduring, evidence of changes in temperature and precipitation.
Rapid changes are occurring across the Arctic where air temperatures are warming twice as fast as the global average temperature. The loss of land-based ice in the Arctic has accelerated in recent decades and since at least 1972, the Arctic has been the dominant source of global sea-level rise. After Greenland, the largest contributor to global sea-level rise from Arctic land ice, are the Arctic’s glaciers. If increases in greenhouse gas concentrations continue at current rates, it is expected that many of the smallest glaciers across the Arctic would disappear entirely by mid-century. Glaciers are important as an indicator of climate change and provide visible evidence of changes in temperature and precipitation.