Climate science - Sept 5
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Ice-free Arctic could be here in 23 years
David Adam, Guardian
The Arctic ice cap has collapsed at an unprecedented rate this summer and levels of sea ice in the region now stand at a record low, scientists said last night. Experts said they were "stunned" by the loss of ice, with an area almost twice as big as Britain disappearing in the last week alone. So much ice has melted this summer that the north-west passage across the top of Canada is fully navigable, and observers say the north-east passage along Russia's Arctic coast could open later this month. If the increased rate of melting continues, the summertime Arctic could be totally free of ice by 2030.
Mark Serreze, an Arctic specialist at the US National Snow and Ice Data Centre at Colorado University in Denver which released the figures, said: "It's amazing. It's simply fallen off a cliff and we're still losing ice." The Arctic has now lost about a third of its ice since satellite measurements began 30 years ago, and the rate of loss has accelerated sharply since 2002.
Dr Serreze said: "If you asked me a couple of years ago when the Arctic could lose all of its ice, then I would have said 2100, or 2070 maybe. But now I think that 2030 is a reasonable estimate. It seems that the Arctic is going to be a very different place within our lifetimes, and certainly within our children's lifetimes."
(5 September 2007)
Contributor Sean Byrne writes:
This seems to prove that Nasa's James Hansen may be right in his argument (based geological records) that polar ice does not melt in a gradual and linear fashion, but flips suddenly from one state to another.
New Times Atlas displays effects of climate change
Creators of the Times Atlas have had to make significant changes to their latest edition because of changes to the world's landscapes caused by climate change, their chief said Sunday.
Cartographers have had to redraw coastlines and reclassify types of land to reflect changes to geographical features like Lake Chad in Africa, which is now 95 percent smaller than it was in 1963.
The last edition of "The Times Comprehensive Atlas Of The World" was published in 2003.
"We can literally see environmental disasters unfolding before our eyes," said Mick Ashworth, the editor-in-chief of the atlas.
"We have a real fear that in the near future, famous geographical features will disappear forever."
(3 September 2007)
Dams 'contributing to global warming'
AAP, The Age (Australia)
The world's dams are contributing millions of tonnes of harmful greenhouse gases and spurring on global warming, according to a US environmental agency.
International Rivers Network executive director Patrick McCully told Brisbane's Riversymposium rotting vegetation and fish found in dams produced surprising amounts of methane - 25 times stronger than carbon dioxide.
"Often it's accepted that hydropower is a climate friendly technology but in fact probably all reservoirs around the world emit greenhouse gases and some of them, especially some of the ones in the tropics, emit very high quantities of greenhouse gases even comparable to, in some cases even much worse than, fossil fuels like coal and gas," Mr McCully said.
He said when water flow was stopped, vegetation and soil in the flooded area and from upstream was left to rot, as well as fish and other animals which died in the dam.
They then released carbon dioxide, methane and nitrous oxide into the air.
"Basically they're factories for converting carbon into methane and methane is a very powerful greenhouse gas - it's less known than carbon dioxide but it's actually about 25 times stronger than carbon dioxide in terms of trapping heat in the atmosphere." Mr McCully said global estimates blamed dams for about a third of all methane emissions worldwide.
(4 September 2007)
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