16 February 2006The Daily YomiuriMakoto Mitsui Yomiuri Shimbun Staff Writer
The level of carbon dioxide in the Earth's atmosphere is likely to grow more than expected as soil bacteria, in response to rising temperatures, break down more organic material and produce more CO2, according to results by an international research team.
The phenomenon will in turn accelerate global warming, and the team's findings serve as a renewed warning to the international community about the need to further reduce CO2 emissions.
It is estimated by environmental scientists that the average global temperature in 2100 will be 1.4 C to 5.8 C higher than in 1990. According to the research team, however, the temperature in 2100 will be even higher, by up to 1.5 C more than current estimates.
The team of researchers from seven countries, including Japan, Britain and the United States, will publish the report in a U.S. scientific journal. The result also will be included in the fourth assessment report of the Intergovernmental Panel for Climate Change scheduled to come out next year.
Current estimates on global temperature rise have been based on the amount of CO2 discharged by industrial activity. Changes caused by rising temperatures in plant photosynthesis or the activity of bacteria will also increase CO2 density, which had not been previously factored in.
The new report was formed after piecing together the results of 11 research teams, including the Frontier Research Center for Global Change and is the first international validation of the ecological effect of bacteria on climate change.
The team found that discharged CO2 from organic material such as leaves and animal bodies broken down by bacteria is larger than the absorbed CO2 from plant photosynthesis. In addition, less CO2 will be absorbed by the ocean due to rises in water temperature.
The team concluded that global warming will progress faster than expected, saying the average global temperature in 2100 will be 0.1 C to 1.5 C higher than current estimates.
The result shows no time should be wasted in preventing progress in global warming, according to specialists.
Of CO2 discharged into the atmosphere by the use of fossil fuels, half is absorbed by plant life in the oceans and by forests. The other half remains in the atmosphere, contributing to the greenhouse effect.
The estimated figure for global temperature in 2100 was calculated by factoring in the present amount of CO2 absorbed. The new report is the first to reveal that there can be a negative chain reaction, as global warming will reduce the CO2 absorbing ability of forests and oceans, and then as a result enhance rising temperatures. All 11 participating teams obtained similar results.
To stop global warming before it seriously influences ecology and human activities, it is necessary to reduce CO2 emissions to a certain extent within this century, according to scientists. If the CO2 absorbing ability of forests and oceans deteriorates drastically, it will be difficult to maintain stable CO2 levels in the air, given that it is impossible to eliminate the CO2 emissions resulting from human activities. The report highlights the necessity to develop effective CO2 reduction measures as soon as possible.
