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Growth of Global Greenhouse Gas Emissions Accelerating - CSIRO
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|by CSIRO - Friday, 1 December 2006
The scientists say this trend, based on data collected over the past 30 years, indicates that recent efforts to cut back on emissions have had little impact on emissions growth.
Marine and atmospheric scientist Dr. Mike Raupach co-chairs the Global Carbon Project at the Commonwealth Scientific and Industrial Research Organization, CSIRO.
He told a meeting of scientists in Tasmania last week that 7.9 billion metric tons of carbon were emitted into the atmosphere as carbon dioxide in 2005 and the rate of increase is quickening.
"From 2000 to 2005, the growth rate of carbon dioxide emissions was more than 2.5 percent per year, whereas in the 1990s it was less than one percent per year," he said.
Emitted by burning coal, oil and gas, and by industrial processes, greenhouse gases blanket the Earth, trapping the heat of the Sun close to the planet. The warming effect is responsible for sea level rise, melting glaciers, extreme weather events, drought, heat waves, and changes in the migratory patterns of birds and animals.
Dr. Paul Fraser, also with CSIRO Marine and Atmospheric Research, says that atmospheric concentrations of carbon dioxide grew by two parts per million in 2005, the fourth year in a row of above average growth.
"To have four years in a row of above average carbon dioxide growth is unprecedented," says Dr. Fraser, who is program manager for the CSIRO Measurement, Processes & Remote Sensing Program.
Dr. Fraser says the 30 year record of air collected at the Australian Bureau of Meteorology’s observation station at Tasmania's Cape Grim, showed growth rates of just over one part per million in the early 1980s, but in recent years carbon dioxide has increased at almost twice this rate.
"The trend over recent years suggests the growth rate is accelerating, signifying that fossil fuels are having an impact on greenhouse gas concentrations in a way we haven’t seen in the past," he said.
"Recent emissions seem to be near the high end of the fossil fuel use scenarios used by the Intergovernmental Panel on Climate Change," Raupach said. "On our current path, it will be difficult to rein in carbon emissions enough to stabilize the atmospheric carbon dioxide concentration at 450 ppm."
While China demonstrates the highest current growth rate in emissions, its emissions per person are still below the global average, Dr. Raupach’s figures show.
China's accumulated contribution since the start of the industrial revolution around the year 1800 is only five percent of the global total.
By comparison, the United States and Europe have each contributed more than 25 percent of accumulated global emissions.
Arid lands of central Australia. Climate changes are expected to have profound impacts on natural ecosystems and their component species. (Photo by Peter Canty courtesy CSIRO)
Dr. Raupach says that on average, nearly half of all emissions from fossil fuel use and land use changes remain in the atmosphere, with the rest being absorbed by the land and oceans.
"When natural variability is smoothed out, 45 percent of emissions have remained in the atmosphere each year over the past 50 years," he says.
He worries that the land and oceans might take up less carbon dioxide in the future than they have in the past, which he says would increase the rate of climate change caused by emissions.
Raupach and Fraser presented their findings last week during the Annual Science Meeting at Tasmania’s Cape Grim Baseline Air Pollution Station, which is managed by the Australian Bureau of Meteorology to monitor and study global atmospheric composition in a program led by CSIRO and the Bureau.
Dr. Paul Fraser's research is directed at understanding the causes of ozone depletion and climate change. (Photo courtesy CSIRO)
Dr. Mike Raupach studies the effects of climate and human land use on the terrestrial cycles of water, energy, carbon and nutrients. (Photo courtesy CSIRO)
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