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CO2 Being Pushed Deep Into the Oceans    [

    Green Light for Greenhouse Gas Burial at Sea
    By Alister Doyle
    Reuters

    Monday 12 February 2007

UN OKs CO2 injection into ocean floor; activists have concerns, however.

    Oslo, Norway - International rules allowing burial of greenhouse gases beneath the seabed entered into force on Saturday in what will be a step toward fighting global warming - if storage costs are cut and leaks can be averted.

    The new rules will permit industrialists to capture heat-trapping gases from big emitters such as coal-fired power plants or steel mills and entomb them offshore - slowing warming while allowing continued use of fossil fuels.

    "Storage of carbon dioxide under the seabed will be allowed from Feb. 10, 2007 under amendments to an international agreement governing the dumping of wastes at sea," the U.N.'s International Maritime Organization said in a statement.

    The new rules, agreed upon in November, amend the U.N.'s London Convention on dumping at sea. Its text had been unclear about whether carbon dioxide, the main greenhouse gas emitted mainly by burning fossil fuels, counted as a pollutant.

    Oil Company Likes Rules

    The changes apply to oceans worldwide and could clear the way to more investment in future subsea carbon storage by governments and companies, despite criticism by environmentalists that there are few safeguards against leaks.

    "This removes a lack of clarity and doubt for investors," said Tore Torp, carbon dioxide storage adviser at Norwegian oil group Statoil, which opened the world's first commercial storage of carbon dioxide in the North Sea in 1996.

    A 2005 U.N. report, however, warned that such storage would only be widely applied if the penalty for emitting carbon dioxide to the atmosphere was $25-$30 a ton - far above current prices in a European Union market that trades emission credits.

    It said carbon burial could be one of the top contributors to slowing warming this century. And in Paris last week, top climate scientists warned that global warming could bring rising seas, more floods, storms and heatwaves by 2100.

    Statoil's view has been that previous rules on ocean storage already allowed carbon burial. On land, national laws generally govern burial of carbon dioxide.

    Who'd Be Responsible for Leaks?

    Greenpeace, which has branded subsea storage as illegal dumping in the past, said the revisions were too hasty.

    "We think the London Convention has not taken objections seriously - such as who will be responsible for leaks, who will oversee the storage, who will clean up," he said.

    Carbon dioxide is not toxic but can lead to acidification of sea water, making it hard for creatures from shrimp to oysters to build shells. In heavy concentrations above ground it can displace air and so asphyxiate animals and plants.

    The amendments pave the way for carbon storage in "sub-seabed geological formations" and say gases injected must consist "overwhelmingly" of carbon dioxide with no added waste.

    Torp said there was uncertainty about what "overwhelmingly" meant - emissions from a coal-fired power plant, for instance, might include some toxic sulfur dioxide.

    Statoil has injected about nine million tons of carbon dioxide in rocks far below its Sleipner gas field in the past decade, with no signs of leaks, Torp said. Following Sleipner, two other big carbon storage sites are in operation in Canada and Algeria and more are planned.

 

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    CO2 Being Pushed Deep Into the Oceans
    By Catherine Brahic
    New Scientist

    Monday 12 February 2007

    Atmospheric carbon dioxide is being pushed deeper into the oceans than previously thought, according to researchers.

    The findings mean the oceans may continue to absorb human emissions of the greenhouse gas more rapidly and for longer, they say, reducing their impact on global warming. But the research is bad news for the marine organisms that are already suffering from ocean acidification.

    Higher levels of CO2 in the atmosphere, caused largely by industrial activities, push the greenhouse gas into ocean waters. Although this process is fairly well understood, scientists have only estimates of the depth at which CO2 from human activities is stored in the oceans.

    "Previous estimates, based on educated assumptions about what the pre-industrial oceans looked like, suggested that in the high latitudes of the North Atlantic, anthropogenic CO2 was not found below 2500 metres," says Douglas Wallace of the University of Kiel, Germany.

    Wallace and colleagues have now published the first measurements showing the location of CO2 from human activities in the North Atlantic. They used data collected during a research cruise in 1981 as a baseline, and then returned to exactly the same sampling locations in 2004.

    "This revealed quite large changes in the CO2 in very deep water, between 3000 metres and 5000 metres," Wallace told New Scientist.

    Dissolving Depth

    If their findings are replicated in the much bigger southern oceans, it could mean that the oceans' capacity to take up CO2 is greater than previously thought.

    While this may soak up some of the CO2 that would otherwise warm the atmosphere, the flipside is that the new findings give further evidence that human activities are rapidly changing the chemistry of the deep oceans.

    "There is a depth in the ocean above which calcium carbonate shells don't dissolve, and below which they do," says Wallace. The findings suggest that the CO2 pumped into the oceans has pushed up this boundary by 400 metres, compared to its level before the industrial age. And the researchers predict that it will be 700 metres shallower by 2050 if CO2 emissions continue their fast growth.

    Wallace says that whether the findings are replicated in the southern oceans remains to be seen, and he is encouraging colleagues to replicate his study there. There may be differences. For example, much of the southern ocean's water sinks to the bottom off the coast of Antarctica. There, sea ice may prevent CO2 entering the water from the atmosphere to the same extent as in the north.

    The scientist who first coined the phrase "ocean acidification," Ken Caldeira, at the Carnegie Institution, California, US, says the extent to which the rising boundary will affect deep-sea corals and shelled organisms remains uncertain. "But when human activities start impacting remote parts of planet, it's a wake-up call that we are interfering in our planet's functioning on a very large scale," he says.

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    Journal reference: Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.0606574104).