notes on imminent doom (cont.)
[cue to James Heartfield to tell us not to worry…]
http://news.bbc.co.uk/2/hi/science/nature/6310869.stm
Melting of glaciers ’speeds up’ By Richard Black Environment correspondent, BBC News website
Mountain glaciers are shrinking three times faster than they were in
the 1980s, scientists have announced.
The World Glacier Monitoring Service, which continuously studies a
sample of 30 glaciers around the world, says the acceleration is down
to climate change.
Its announcement came as climate scientists convened in Paris to
decide the final wording of a major report.
There is reported to be some disagreement over what forecasts they
will make for sea level rise.
But whatever form of words they agree on, the Intergovernmental Panel
on Climate Change (IPCC) will declare that human-induced climate
change is happening and needs to be tackled.
“[The report] embodies substantial new research, it addresses gaps
that existed in our knowledge earlier, it has reduced existing
uncertainties,” IPCC chairman Rajendra Pachauri told reporters at a
news briefing in Paris.
“I hope policies and actions will be formed to address the problem.”
The report, due out on Friday, forms the first part of the IPCC’s
Fourth Assessment Report, and will be the latest definitive
assessment of climate science.
Melting away
Of all the various features that make up the surface of the Earth,
glaciers are perhaps showing the starkest signs of rising temperatures.
The World Glacier Monitoring Service (WGMS), based in Switzerland,
continuously studies a set of 30 mountain glaciers in different parts
of the world. It is not quite a representative sample of all mountain
glaciers, but does give a reliable indication of global trends.
MOUNTAIN GLACIERS DECLINE
Data comes from sample of 30 mountain glaciers
Glaciers have different densities, so thinning is expressed in metres
of water equivalent (mwe)
One mwe is roughly equivalent to 1.1m of ice
The latest survey, just released, shows accelerating decline. During
2005, this sample of 30 glaciers became, on average, 60-70cm thinner.
This figure is 1.6 times more than the average annual loss during the
1990s, and three times faster than in the 1980s.
With mountain glaciers typically only tens of metres thick, this
meant, said WGMS director Wilfried Haeberli, that many would
disappear on a timescale of decades if the trend continued.
“We can say there were times during the warmer periods of the last
10,000 years when glaciers have been comparable to what they are
now,” he told the BBC News website.
“But it is not the past that worries us, it is the future. With the
scenarios predicted, we will enter conditions which we have not seen
in the past 10,000 years, and perhaps conditions which mankind has
never experienced.”
Last year, WGMS scientists forecast that the Alps would lose up to
three-quarters of their glaciers during the coming century.
The WGMS is closely allied to the United Nations Environment
Programme, whose executive director Achim Steiner commented:
“Glaciers are important sources of water for many important rivers
upon which people depend for drinking water, agriculture and
industrial purposes.
“The findings… should strengthen the resolve of governments to act
now to reduce greenhouse gas emissions.”
Rough seas
The IPCC report due out on Friday is likely to contain stronger
wording than its previous assessment, in 2001, on the likelihood that
human activities are principally responsible for the climatic changes
observed around the world.
The 2001 report forecast that by the end of this century,
temperatures would have risen by between 1.4C and 5.8C.
The new report is likely to reduce the range of uncertainty, though
not rule out the possibility entirely of increases in the order of 5.8C.
But there is reported to be disagreement over the wording on expected
sea level rise.
A bigger network of tide gauges and other instruments has enabled
researchers to conclude that the sea level is on average rising by
about 2mm per year, or 20cm per century.
This is one of the factors which led to earlier drafts of this report
projecting rises by the end of the century which were a lot less than
the maximum figure of 88cm contained in the 2001 version.
But some scientists are arguing that recent observations of the
Greenland and West Antarctic ice sheets suggest a major melt may be
commencing. This, they say, should be reflected in the eventual IPCC
projections.