Zurich/Nairobi, 30 January 2007 – Mountain glaciers around
the world continue to melt, with new, still tentative figures
for 2005 indicating a further average thickness reduction
for a set of reference glaciers of 0.6 metre water equivalent
(w.e.). On average, one metre water equivalent corresponds
to 1.1 metre ice thickness.
The new data confirms the trend in accelerated ice loss
during the past two and a half decades and brings the average
thickness loss since 1980 of the 30 reference glaciers of
nine mountain ranges at about 9.6 metre w.e. These results
come from glacier mass balance measurements collected by
scientists all over the world and published by the World
Glacier Monitoring Service (WGMS) in Zurich, Switzerland.
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. 30 of these
glaciers have continuous mass balance measurement series
since 1980. Their average annual ice loss since the year
2000 was about 0.6 metre w.e., which is 1.6 times more than
the average of the 11000s and three times the loss rate
of the 1980s. Comprehensive data for the year 2006 are not
yet available, but as it was one of the warmest years in
many parts of the world, it is expected that the downward
trend will continue.
Achim Steiner, UN Under-Secretary General and UNEP Executive
Director, said: “This is the most authorative, 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. Glaciers across the globe
are important sources of water for many important rivers—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
Michael Zemp, a glaciologist and research associate at
the WGMS said: “Today, the glacier surface is much smaller
than in the 1980s, this means that the climatic forcing
has continued since then. The recent increase in rates of
ice loss over reducing glacier surface areas leaves no doubt
about the accelerated change in climatic conditions”, he
says.
The WGMS collects and publishes standardised 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 and one of the headline indicators
presented in the GEO Yearbook series.
The new preliminary findings also underlines the important
of this year’s 5 June World Environment Day theme Melting
Ice- A Hot Topic?. The main international celebrations,
which also coincide with International Polar Year, will
be held in Norway.
Links
World Glacier Monitoring Service: http://www.wgms.ch
United Nations Environment Programme, Global Environment
Outlook: http://www.unep.org/geo/ United Nations Environment
Programme, GEO Data Portal: http://geodata.grid.unep.ch
Supplementary figures
Fig. 1: Mean annual net balance (thickness change) of 30
glaciers* (27 in 2005) and nine mountain ranges.
Fig. 2: Cumulative mean annual net balance (thickness change)
of 30 glaciers* (27 in 2005) and nine mountain ranges.
* Place and Urumqihe S. No. 1 (Canada); South Cascade,
Gulkana and Wolverine (USA); Austre Broeggerbreen, Midre
Lovenbreen, Engabreen, Alfotbreen, Nigardsbreen,, Grasubreen,,
Storbreen, Hellstugubreen, and Hardangerjoekulen (Norway);
Echaurren Norte (Chili); Storglaciaeren (Sweden); Saint
Sorlin and Sarennes (France); Silvretta and Gries (Switzerland);
Sonnblickkees, Vernagtferner, Kesselwandferner, and Hintereisferner
(Austria); Careser (Italy), Maliy Aktru, Leviy Aktru , No.
125 and Djankuat (Russia), Ts. Tuyuksuyskiy (Kazachstan),
Fig. 3-5: Vernagtferner, Austria. Annual mass balance measurements
were initiated on this Alpine glacier in 1964. Since then,
the ice loss cumulated to almost 12 metre w.e., with a thickness
loss of about 0.5 metre w.e. during 2005. The photos, taken
by O. Gruber (1912), H. Rentsch (1968) and M. Siebers (2003),
are kindly provided by the Commission for Glaciology of
the Bavarian Academy of Sciences and Humanities.
