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Methane gushes from sea floor: Ominous eruptions
He and his colleagues at the Geological Survey of Canada have been sizing them up from ships. They have sent down remotely operated vehicles for a closer look. And they have been peering into holes in the sea ice created as the gas bubbles to the surface. "They are fantastic things," Mr. Dallimore says of the "pingo-like features," or mud volcanoes, that are one of the wilder cards in the global warming equation. Along with the methane bubbling out of the metres-high mounds on the sea floor, Mr. Dallimore says the gas is seeping out of permafrost in some areas. Scientists do not know how much gas is being released, if the rate of release is increasing or what the impact will be on the atmosphere. "It is a huge gap in our scientific understanding," says Mr. Dallimore, echoing international reports that point to escaping methane as one of the ominous unknowns associated with the profound change underway at the top of the planet. While there may still be debate about the cause of the change, there is little doubt the Arctic is being radically redefined. And leading researchers say it is time to get serious about not only reducing pollution linked to the warming, but to filling in the important blanks in knowledge and figuring out how to adapt to the change. Polar ice has been shrinking at a rate of about 74,000 square kilometres annually for the last 30 years, according to David Barber, an ice specialist at the University of Manitoba. That means enough ice to cover Lake Superior vanishes each year. Mr. Barber predicts the fabled Northwest Passage could be open for summer shipping within decades. The Arctic ice is withdrawing so fast, he and some of his colleagues predict that by 2050 it may be non-existent in summer. "It could be as early as 2020, or it could be 2050," Mr. Barber says. "This is not an insignificant thing, this is a very major change in how the Arctic system functions. We're talking about a change over 50 years, 80 years at the outside, which we haven't seen on the planet Earth for at least a million years. This is very rapid." Greenland's ice sheet is also on the move, sliding into the sea at about 12 kilometres a year, dumping icebergs and meltwater at twice the rate it did a decade ago. "In the next 10 years, it wouldn't surprise me if the rate doubled again," Eric Rignot of NASA's Jet Propulsion Laboratory said after publishing the findings in the journal Science last month. Low-lying coastal communities are already feeling the impact of increased wave action and erosion that comes with more open water and some may have to relocate to more solid ground. Building foundations and airport runways are buckling as permafrost melts, prompting civil engineers in Nunavut and Northern Quebec to start drawing up remediation plans. But there is little anyone can do for the animals and other life forms that will be stranded as temperatures climb and the Arctic's icy cloak lifts. "If you live on the sea ice like the polar bear, you are in big trouble -- your habitat is disappearing," says biologist John Smol of Queen's University, who is documenting the transformation underway in freshwater lakes in Nunavut. He, like many Arctic researchers, stresses the need for the public and politicians to wake up to the profound nature of the change. "People have still not caught on to how serious it is," says Mr. Smol, the current holder of the country's top science prize: the Herzberg gold medal. "I believe climactic warming is by far the most serious issue we should be thinking about, over terrorism and over all the other things that make headlines." Some see benefits to the receding ice, such as summer shipping and easier access to Arctic riches of oil, gas, minerals and diamonds. But Mr. Smol and Mr. Barber caution that any opportunities -- "and I hesitate to call them opportunities," says Mr. Smol -- will be offset by challenges. Salmon showing up in the Arctic waters might lead to new fisheries, but other species will be displaced. Increased shipping is sure to be associated with accidents. And while permafrost is expected to give way to more forest and agriculture, the big melt could create havoc for pipelines, runways and roads designed to sit on, or in, frozen ground. Then there is the vast store of carbon and frozen methane gas, known as gas hydrates, that have been locked in permafrost and Arctic seabeds for millennia. Energy companies and scientists like Mr. Dallimore are exploring the possibility of exploiting the frozen gas hydrates as a new source of energy. But there is concern hydrates may escape as temperatures rise and permafrost melts. Methane is 20 times more efficient as a greenhouse gas than the carbon dioxide that is produced by burning fossil fuels and associated with global warming. No one knows how much of the Arctic gas will escape as temperatures rise. Mr. Dallimore and his colleagues hope to get a better read on the potential threat as part of a project -- planned for the International Polar Year in 2007-8 -- to assess the methane bubbling out of the sea and ground in Canada's North. "Whether the gas is from degrading permafrost or whether it is from deep gas hydrates, we don't know at this point," Mr. Dallimore says. "But we need to find out."
Posted by: lotp 2006-03-08 |
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