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NASA Says Northern Ozone Pollution Spurs Arctic Warming    [

    Level of Climate Change Gases Hits Record High
    By Fiona Harvey
    The Financial Times

    Wednesday 15 March 2006

    London - The atmosphere's level of greenhouse gases associated with climate change is hitting record highs, two prominent scientific organisations said yesterday.

    A bulletin on greenhouse gas levels by the World Meteorological Organisation (WMO) said there were 377 parts per million of carbon dioxide in the atmosphere in 2004, up from around 280ppm before the industrial revolution.

    One of the highest year-on-year rises ever in the level of carbon dioxide was recorded at 1.8ppm.

    But the US National Oceanic and Atmospheric Administration, using a slightly different methodology, said last year's rise was even greater at 2.6ppm, and overall carbon dioxide levels were at 381ppm.

    Carbon dioxide - produced by burning fossil fuels - is the most abundant greenhouse gas in the atmosphere, and is the gas that most concerns climate scientists, because of its warming effect on the earth.

    But levels of methane and nitrous oxide, both of which have a much greater effect on the climate but are present in the air in much smaller quantities, have also risen.

    Nitrous oxide is a potent greenhouse gas, the concentration of which has been rising by about 0.8 parts per billion per year since 1988.

    At least a third of the amount of the gas in the atmosphere is the result of human activities such as fuel combustion, biomass burning, fertiliser use and some industrial processes.

    But the levels of methane - produced by human activity such as oil and gas production and agriculture, as well as some natural processes - were showing signs of reaching a plateau, the WMO said.

    Tony Juniper, director of the campaigning group Friends of the Earth, said urgent action was needed to curb emissions: "If we take action now we can still avoid the worst impacts of climate change by investing in clean renewable technology and energy efficiency.

    "The attempts by government and business to reduce emissions have lacked ambition and there hasn't been the effort put in that is needed."

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    NASA Says Northern Ozone Pollution Spurs Arctic Warming
    By Deborah Zabarenko
    Reuters

    Wednesday 15 March 2006

    Washington - Ozone pollution in the Northern Hemisphere, churned out by factories and vehicles that burn fossil fuels, is a major factor in the dramatic warming of the Arctic zone, NASA climate scientists reported Tuesday.

    This finding is surprising, since ozone has been considered a minor player in the study of global climate change, according to Drew Shindell, a research scientist at NASA's Goddard Institute for Space Studies in New York City.

    Carbon dioxide has long been considered a key cause of overall global warming, because it remains in the atmosphere for a long time, Shindell said in a telephone interview.

    But ozone - the damaging, heat-trapping tropospheric ozone encountered at lower levels of the atmosphere, as opposed to the protective ozone observed at higher altitude - was seen as fairly perishable and therefore less of a factor, he said.

    Globally, ozone accounts for perhaps one-seventh of the global warming and climate change that carbon dioxide does, Shindell said. However, a new study of climate change over the past 100 years indicates that ozone may be responsible for as much as 50 percent of the warming in the Arctic zone.

    This is because many of the world's most highly industrialized nations are in the Northern Hemisphere, and at relatively high latitudes. For most of the year, that means the ozone produced in these countries is blown by prevailing winds north and east, toward the Arctic Circle.

    "Instead of being this tiny player, (ozone) can be more like 30 or 40 or even 50 percent of the cause of warming that we're seeing in the Arctic now," Shindell said. "It's very dramatic."

    In computer models using climate data going back to 1880, environmental scientists found Arctic temperatures remained normal until about 1950. After that, the model shows higher temperatures, widely spread around the Arctic region.

    This rise in temperatures is linked to the rise in tropospheric ozone at northern latitudes, Shindell said.

    "Global warming has really taken off since the 1970s," he said. "The warming in the past several decades has been more than it was the whole previous record, which is about 100 years before that."

    Arctic warming has been more extreme than global warming overall, he said, because as snow and ice melt they uncover darker-colored ground or water that absorb heat, accelerating warming.