Global Glacier Volume Change (1960–1998)

The line with closed circles shows that glaciers worldwide have shrunk over the last 30 years.

The line with open circles represents worldwide changes in glacier volume from year to year. To interpret this line, consult the scale on the left side of the graph, which shows the annual change in glacier volume in cubic kilometers. Only four years have points above the 0 line—meaning that glaciers gained in volume only four years out of 28.

Glaciers and ice sheets currently cover 10% of the land area on earth and contain about 75% of its freshwater. Because of their greater size and thickness, glaciers respond more slowly than snow and sea ice to short-term changes in weather and climate. Scientists can therefore keep track of fluctuations in glacial volume worldwide as one indicator of long-term climate trends.

The data on this graph comes primarily from aerial and satellite photography. Some scientists have also studied eighteenth century paintings of the Swiss Alps and compared them with present-day photographs to track how glaciers have responded to climate change over the last two centuries.

The data on this graph come from field measurements on glaciers around the world, which are used to estimate the change in the unmeasured glaciers. Aerial and satellite photography also support the field evidence of glacier shrinkage.