The end for small glaciers

Richard A. Lovett in Nature News: In the most comprehensive study of mountain glaciers and small ice caps to date, a team of US and Canadian scientists has projected that most of the world's smaller glaciers will be gone by 2100. The finding confirms that the Intergovernmental Panel on Climate Change (IPCC) — the scientific group assessing climate risk — was correct in estimating that by that date, complete or partial melting of smaller glaciers will contribute about the same amount to sea-level rise as meltwater from the giant ice sheets of Antarctica and Greenland. The study also confirms that the IPCC was wrong in stating that Himalayan glaciers would disappear by 2035.

The study, in Nature Geoscience, found that half of the world's smallest glaciers, with a surface area less than 5 square kilometres, will disappear entirely, with possible implications for communities dependent on them for water supplies. Overall, the melting of small glaciers and ice caps alone will contribute about 12 centimetres of sea level rise by 2100, based on an average of ten global climate models.

"While the IPCC review process clearly failed in the Himalayan instance," says IPCC member and forest ecologist Steve Running of the University of Montana in Missoula, "the estimate of overall mountain-glacier contribution to sea-level rise was about right." Earlier studies used by the IPCC had found approximately the same result, but were forced to extrapolate from a relatively small number of glaciers. The new study was based on a total of 120,229 mountain glaciers and 2,638 ice caps…

Franz-Josef Glacier in New Zealand, shot by Alexander Klink, Wikimedia Commons, under the Creative Commons Attribution 3.0 Unported license