Fifty-Year Record Shows Fast Shrinking Glaciers
10.08.2009 - Ice & Snow, Other, Arctic
The United States Geological Survey (USGS) has been keeping track of data on glacier change for fifty years. Using three benchmark glaciers in the United States situated in three different climatic regions, researchers found that the glaciers had dramatically shrunk over time.
The three glaciers studied were:
- South Cascade Glacier (Cascade Mountains, Washington State)
- Wolverine Glacier (Kenai Peninsula, Alaska)
- Gulkana Glacier (interior Alaska)
For all glaciers:
- the cumulative net balances (= total loss or gain of glacier mass since the beginning of the study period) are a rapid and sustained mass loss. Researchers suspect this to be due to recent climate changes.
- summer balance record (= used to reveal whether variations in temperature or precipitation are primary factors for observed changes) results in consistently more ablation during the period 1987-2004. When coupled with a reduction in accumulation, glaciers show very negative net balances.
The USGS study is the first to offer such definite evidence of this shrinkage. Worldwide, most glaciers are losing mass and some are disappearing. USGC scientists point out that a drop in runoff has a dramatic impact on the water temperature and the downstream ecosystem. It also means less available drinking water.
Because the three glaciers are situated in such different climatic regions and at varying elevations, the results of this study will be extrapolated to thousands of other North American glaciers.
