The amount of global warming-causing greenhouse gases in the atmosphere rose to a new high in 2010, and the rate of increase has accelerated, the UN weather agency said on Monday. Levels of carbon dioxide — a greenhouse gas and major contributor to climate change — rose by 2.3 parts per million between 2009 and 2010, higher than the average for the past decade of 2.0 parts per million, a new report by the World Meteorological Organisation found. “The atmospheric burden of greenhouse gases due to human activities has yet again reached record levels since pre-industrial time,” said WMO Secretary-General Michel Jarraud. Greenhouse gases trap radiation within the earth’s atmosphere, causing it to warm. The last two decades have seen a 29 percent increase in radiative forcing — the warming effect — from greenhouse gases, the report said. Scientists attributed the continuing rise in levels of carbon dioxide, which contributes about 64 percent to climate warming, to fossil fuel burning, deforestation and changes in land use. Methane, produced by cattle-rearing and landfills, is the second most important greenhouse gas after carbon dioxide, followed by nitrous oxide. The WMO’s annual Greenhouse Gas Bulletin said methane levels rose 5 parts per billion or 0.28 percent in 2009-2010 after a period of relative stabilisation from 1999 to 2006, possibly due to the thawing of the Northern permafrost and increased emissions from tropical wetlands. Nitrous oxide, emitted into the atmosphere from natural and man-made sources, including biomass burning and fertiliser use, rose 0.8 parts per billion to 323.2 in 2010 — 20 percent higher than in the pre-industrial era, defined as the period before 1750. Its impact on the climate over a 100-year period was said to be 298 times greater than equal emissions of carbon dioxide.
