Glacier Changes in Western North America: Effects on Sea Level and Climatic Implications

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ABSTRACTEchelemeyerOPP-0327067Over the past decade the elevation profiles of about 100 glaciers in northwestern North America have been measured, many of them more than once. Used along with old maps, these permit changes in surface elevation and volume to be calculated for different time intervals. This is a twoyear follow-up study to complete data processing and archiving, and to perform several interpretative tasks. The first of these tasks will be to improve techniques for extrapolating the changes on measured glaciers to obtain the volume changes of unmeasured ones. This will require the compilation of a regional map of late summer snowlines to help define climate regions. The second interpretative task involves removing the effects of glacier flow from the data, so that the changes can be related to climate alone. The final task is to interpret these corrected changes interms of local and regional climate, and to predict what will happen to the glaciers in the future under specified climate scenarios.Broader Impacts: The research will be carried out from a scientific perspective, but there are several applications. The most obvious is the refined determination of how much the glaciers of Alaska have contributed to the rise in sea level, and what future contributions are likely to be under various climate scenarios. The recent contribution has been much larger than originally predicted, and may exceed that from the major ice sheets. A recent paper describing these results attracted worldwide press attention. The other application relates to engineering: the effect of glaciers and glacier thinning on water supply. One example in Alaska recently re-surfaced when a congressmanurged the revival of a proposal for a huge hydro-power development project in the Susitna basin of the Alaska Range.