File:Glacier Mass Balance Map.png
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Description
The effective rate of change in glacier thickness, also known as the glaciological mass balance, is a measure of the average change in a glacier's thickness after correcting for density variations associated with the compaction of snow and conversion to ice. The map shows the average annual rate of thinning since 1970 for the 173 glaciers that have been measured at least 5 times between 1970 and 2004 (Dyurgerov and Meier 2005). Larger changes are plotted as larger circles and towards the back.
All survey regions except Scandinavia show a net thinning. This widespread glacier retreat is generally regarded as a sign of global warming.
During this period, 83% of surveyed glaciers showed thinning with an average loss across all glaciers of 0.31 m/yr. The most rapidly growing glacier in the sample is Engabreen glacier in Norway with a thickening of 0.64 m/yr. The most rapidly shrinking was Ivory glacier in New Zealand which was thinning at 2.4 m/yr. Ivory glacier had totally disintegrated by circa 1988 [1].
Copyright
This figure was originally prepared by Robert A. Rohde from published data.
This image is an original work created for Global Warming Art by Robert A. Rohde.
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Notes
This sample of mountain glaciers excludes the primary ice sheets of Greenland and Antarctica.
It should be acknowledged that glacier sampling is heavily biased towards North America and Europe. Substantial unsampled mountain glaciers exist in South America, Asia and the margins of Antarctica. However, the glacier distriution is also not uniform. Africa has only a handful of glaciers and continental Australia has none. Despite their relative importance, none of the marginal Antarctic glaciers have had their mass balance sampled at least 5 times since 1970.
These estimates of ice sheet thinning do not include glacier mass lost due to iceberg calving. Such calving is not significant for most mountain glaciers since only a small proportion of these glaciers terminate in large bodies of water.
Reference
- [abstract] [full text] Dyurgerov, Mark B. and Mark F. Meier (2005). Glaciers and the Changing Earth System: A 2004 Snapshot. Institute of Arctic and Alpine Research. Occasional Paper 58.
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 03:57, 5 March 2006 | 650×477 (108 KB) | Robert A. Rohde (Talk | contribs) |



