Melting of Mountain Glaciers Accelerating

Mountain glaciers around the world melted from 2000 to 2005 at 1.6 times the average loss rate of the 1990s and three times that of the 1980s, with much of the accelerated change attributable to human-induced climate change, according to tentative figures in a new United Nations-backed report released today.

“This is the most authoritative, comprehensive and up-to-date information on glaciers world-wide and as such underlines the rapid changes occurring on the planet as a result of climate change,” UN Environment Programme (UNEP) Executive Director Achim Steiner said, noting their importance as sources for many rivers upon which people depend for drinking water, agriculture and industrial purposes.

“The findings confirm the science of human-induced climate change, confirmation that will be further underlined when the Intergovernmental Panel on Climate Change unveil their next report on 2 February. These findings should strengthen the resolve of governments to act now to reduce greenhouse gas emissions and put in place the medium to longer term strategies necessary to avert dangerous climate change,” he added.

According to the figures, the 2000-2005 period saw an average thickness loss for a set of reference glaciers of 0.6 metre water equivalent, confirming the trend in accelerated ice loss during the past two and a half decades and bringing the average reduction since 1980 of the 30 reference glaciers of nine mountain ranges to about 9.6-metres water equivalent. On average, one metre water equivalent corresponds to 1.1 metre ice thickness. The results come from glacier mass balance measurements collected by scientists all over the world and published by the World Glacier Monitoring Service (www.wgms.ch/about.html ) in Zurich, Switzerland.

The WGMS collects standardized glacier data which are considered to be among the best natural indicators of climate change. Scientific measurements relate to the so-called ‘net mass balance’ of glaciers, which can be seen as their overall ice thickness change. The long-term monitoring of glacier mass balance produces one of the most essential variables required for the regular assessment reports on global climate monitoring. As such, the glacier mass balance data are an important contribution to UNEP’s Global Environment Outlook (GEO) report.

The preliminary data on glacier change for the year 2005 from 80 glaciers was reported to the WGMS from the majority of the glaciated mountain ranges of the world. Of these, 30 glaciers have continuous mass balance measurement series since 1980. Comprehensive data for the year 2006 are not yet available, but as it was one of the warmest years in many years in many parts of the world, it is expected that the downward trend will continue. “Today, the glacier surface is much smaller than in the 1980s, this means that the climatic forcing has continued since then,” Michael Zemp, a glaciologist and research associate at the WGMS said. “The recent increase in rates of ice loss over reducing glacier surface areas leaves no doubt about the accelerated change in climatic conditions.”