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Methane now bubbling from Beaufort Sea
CK Paull, W Ussler, SR Dallimore, SM Blasco, TD Lorenson, H Melling, BE Medioli, FM Nixon, FA McLaughlin, American Geophysical Union
The Arctic shelf is currently undergoing dramatic thermal changes caused by the continued warming associated with Holocene sea level rise.
During this transgression, comparatively warm waters have flooded over cold permafrost areas of the Arctic Shelf. A thermal pulse of more than 10°C is still propagating down into the submerged sediment and may be decomposing gas hydrate as well as permafrost.
A search for gas venting on the Arctic seafloor focused on pingo-like-features (PLFs) on the Beaufort Sea Shelf because they may be a direct consequence of gas hydrate decomposition at depth. Vibracores collected from eight PLFs had systematically elevated methane concentrations. ROV observations revealed streams of methane-rich gas bubbles coming from the crests of PLFs. We offer a scenario of how PLFs may be growing offshore as a result of gas pressure associated with gas hydrate decomposition.
(5 Jan 2007)
The AGU paper above costs $9, but there is this 8min Canadian Broadcasting Commission interview with co-author Scott Dallimore (4MB mp3).
Ice island the size of London threatens rigs
Jonathan Owen, The Independent
An enormous iceberg the size of central London is causing alarm among scientists, who predict that it could be on the move in a matter of months, posing a potential threat to shipping and oil rigs in Arctic waters.
The two-million-ton, 25-square-mile block of ice is part of the Ayles ice shelf. Its existence only recently came to light thanks to satellite images from Nasa. Lying 30 miles off Canada’s Ellesmere Island, it will be on the move in the summer, as temperatures rise and break up the surrounding pack ice.
“The potential issue here is that the ice island could go into the oil rigs in the Beaufort Sea,” said Dr Luke Copland, a specialist in ice masses based at the University of Ottawa. “This hasn’t happened in the past, but it could happen.”
The ice could move several hundred miles over the summer, taking it closer to busy shipping routes for oil and gas. “If it ever came on a collision course with an oil rig, it is unlikely that we would be able to do much to stop it,” said Dr Copland. “Maybe you would have to consider aerial bombardment to break it up, or use lots of tugs to try and move it, but it would be a lot of ice to move.”
(31 Jan 2007)
Race against the clock
W Frew & S Peatling, Sydney Morning Herald
Last year a series of lakes formed on the vast body of ice that covers most of Greenland. Acting like a lubricant, the water quickly made its way to the base of the ice sheet, forcing giant slabs of ice to rise, then slide into the ocean. The speed at which the ice broke off shocked many scientists.
“We used to think that it would take 10,000 years for melting at the surface of an ice sheet to penetrate down to the bottom. Now we know it doesn’t take 10,000 years; it takes 10 seconds,” says Richard Alley, a professor of geosciences at Pennsylvania State University.
In a newspaper interview a few months ago, Alley expressed the fear shared by others that the scientific community had underestimated the role melting ice could have on rising sea levels and weather patterns. ..
“This report will ring alarm bells,” says the director of the Australia Institute, Dr Clive Hamilton, “but it won’t ring them loudly enough.” Hamilton, who has tracked the science and politics of the climate change debate for more than a decade, says some of the research upon which the report is based is already out of date, and some research has not been included because it is too controversial.
“The science has changed a lot in the past 12 months and it is all very scary and it does not seem to be reflected in the report,” Hamilton says. “Sceptics claim the science is an exaggeration but in fact it is the opposite. The science is very conservative.”
The Paris report was expected to predict sea level rises of between 19 and 58 centimetres by 2100, compared with a much wider range of nine to 88 centimetres in the 2001 report. The range was narrowed because of improvements to the modelling used in past reports. However, it does not take into account the new research and evidence about ice melting at the poles. One of the world’s leading climate researchers, the Australian Dr Barrie Pittock, says the panel’s report represents a “snapshot” or summary of the science literature as of early last year.
However, the former head of CSIRO’s climate impact group and author of Climate Change: Turning Up the Heat, says the conservative nature of the scientific profession, the requirement for the panel’s many scientists to reach consensus on all of the material in the report, plus a cut-off date early last year for research papers considered by the panel, means the report may not reflect the balance of evidence that seems to be swinging toward a more extreme outcome for the climate. ..
(3 Feb 2007)
Article also discusses past studies by CSIRO correctly forecasting worsening drought and bushfires in Australia, and government inaction. See also Temperature predictions conservative: Flannery. Mr Flannery’s recent honour of being named Australian of the Year still has me puzzled, he doesn’t even play cricket (cricket being the only science Prime Miniature Howard recognises).-LJ
