June 5, 2007

environment day


june 5

environment day

The futures of hundreds of millions of people across the world will be affected by declines in snow cover, sea ice, glaciers, permafrost and lake ice a new and unique report launched to mark World Environment Day (WED) says.
Impacts are likely to include significant changes in the availability of water supplies for drinking and agriculture, rising sea levels affecting low lying coasts and islands and an increase in hazards such as subsidence of currently frozen land.
An estimated 40 per cent of the world's population could be affected by loss of snow and glaciers on the mountains of Asia says the UN Environment Programme (UNEP) in the Global Outlook for Ice and Snow.
Similar challenges are facing countries, communities, farmers and power generators in the Alps to the Andes and the Pyrenees, says the report.
Melting ice and snow are also likely to increase hazards including avalanches and floods from the build up of potentially unstable glacial lakes. These can burst their ice and soil dams sending walls of water down valleys at speeds close to that of a modern anti-tank missile.
Rising temperatures and the thawing of frozen land or 'permafrost' is triggering the expansion of existing- and the emergence of new- water bodies in places like Siberia.
These are bubbling methane into the atmosphere with emissions so forceful they can keep holes open on the lakes' icy surfaces even during sub zero winter months.
Methane is a powerful global warming gas and new estimates indicate that the quantities emerging from these so called thermokast lakes is up to five times higher than had previously been supposed.
Meanwhile less snow and sea ice are leading to more of the sun's heat being absorbed by the land and the polar oceans which in turn may speed up global climate change.
These are among the 'feedbacks' which some experts fear could trigger even faster or more abrupt climatic changes with even wider-ranging impacts on people, economies and wildlife.


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