Black carbon pollution emerges as major player in global warmingMarch 24, 2008Black carbon, a form of particulate air pollution most often produced from biomass burning, cooking with solid fuels and diesel exhaust, has a warming effect in the atmosphere three to four times greater than prevailing estimates, according to scientists in an upcoming review article in the journal Nature Geoscience. Scripps Institution of Oceanography at UC San Diego atmospheric scientist V. Ramanathan and University of Iowa chemical engineer Greg Carmichael, said that soot and other forms of black carbon could have as much as 60 percent of the current global warming effect of carbon dioxide, more than that of any greenhouse gas besides CO2. The researchers also noted, however, that mitigation would have immediate societal benefits in addition to the long term effect of reducing greenhouse gas emissions. The article, "Global and regional climate changes due to black carbon," will be posted in the online version of Nature Geoscience on Sunday, March 23.
"Observationally based studies such as ours are converging on the same large magnitude of black carbon heating as modeling studies from Stanford, Caltech and NASA," said Ramanathan. "We now have to examine if black carbon is also having a large role in the retreat of arctic sea ice and Himalayan glaciers as suggested by recent studies." In the paper, Ramanathan and Carmichael integrated observed data from satellites, aircraft and surface instruments about the warming effect of black carbon and found that its forcing, or warming effect in the atmosphere, is about 0.9 watts per meter squared. That compares to estimates of between 0.2 watts per meter squared and 0.4 watts per meter squared that were agreed upon as a consensus estimate in a report released last year by the Intergovernmental Panel on Climate Change (IPCC), a U.N.-sponsored agency that periodically synthesizes the body of climate change research. Ramanathan and Carmichael said the conservative estimates are based on widely used computer model simulations that do not take into account the amplification of black carbon's warming effect when mixed with other aerosols such as sulfates. The models also do not adequately represent the full range of altitudes at which the warming effect occurs. The most recent observations, in contrast, have found significant black carbon warming effects at altitudes in the range of 2 kilometers (6,500 feet), levels at which black carbon particles absorb not only sunlight but also solar energy reflected by clouds at lower altitudes. Between 25 and 35 percent of black carbon in the global atmosphere comes from China and India, emitted from the burning of wood and cow dung in household cooking and through the use of coal to heat homes. Countries in Europe and elsewhere that rely heavily on diesel fuel for transportation also contribute large amounts. "Per capita emissions of black carbon from the United States and some European countries are still comparable to those from south Asia and east Asia," Ramanathan said. In south Asia, pollution often forms a prevalent brownish haze that has been termed the "atmospheric brown cloud." Ramanathan's previous research has indicated that the warming effects of this smog appear to be accelerating the melt of Himalayan glaciers that provide billions of people throughout Asia with drinking water. In addition, the inhalation of smoke during indoor cooking has been linked to the deaths of an estimated 400,000 women and children in south and east Asia. Elimination of black carbon, a contributor to global warming and a public health hazard, offers a nearly instant return on investment, the researchers said. Black carbon particles only remain airborne for weeks at most compared to carbon dioxide, which remains in the atmosphere for more than a century. In addition, technology that could substantially reduce black carbon emissions already exists in the form of commercially available products. Ramanathan said that an observation program for which he is currently seeking corporate sponsorship could dramatically illustrate the benefits. Known as Project Surya, the proposed venture would provide some 20,000 rural Indian households with smoke-free cookers and equipped to transmit data. At the same time, a team of researchers led by Ramanathan would observe air pollution levels in the region to measure the effect of the cookers. Carmichael said he hopes that the paper's presentation of the immediacy of the benefits will make it easier to generate political and regulatory momentum toward reduction of black carbon emissions. "It offers a chance to get better traction for implementing strategies for reducing black carbon," he said. The National Science Foundation, the National Oceanic and Atmospheric Administration and the National Aeronautics and Space Administration funded the review. University of California - San Diego | |||||||
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Related Black Carbon News Articles Man-made soot contributed to warming in Greenland in the early 20th century New research shows that industrial development in North America between 1850 and 1950 greatly increased the amount of black carbon--commonly known as soot-- that fell on Greenland's glaciers and ice sheets. Scientists track impact of Asian dust and pollution on clouds, climate change Scientists using one of the nation's newest and most capable research aircraft are launching a far-reaching field project this month to study plumes of airborne dust and pollutants that originate in Asia and journey to North America. Scientists to track impact of Asian dust and pollution on clouds, climate change Scientists using one of the nation's newest and most capable research aircraft are launching a far-reaching field project this month to study plumes of airborne dust and pollutants that originate in Asia and journey to North America. Transported Black Carbon a Significant Player in Pacific Ocean Climate Soot and other particulate pollution from Asian sources make up more than 75 percent of black carbon transported at high altitudes, according to a Scripps Institution of Oceanography, UC San Diego-led study. NASA probes the sources of the world's tiny pollutants Pinpointing pollutant sources is an important part of the ongoing battle to improve air quality and to understand its impact on climate. Scientists using NASA data recently tracked the path and distribution of aerosols — tiny particles suspended in the air — to link their region of origin and source type with their tendencies to warm or cool the atmosphere. Soot from wood stoves in developing world impacts global warming more than expected New measurements of soot produced by traditional cook stoves used in developing countries suggest that these stoves emit more harmful smoke particles and could have a much greater impact on global climate change than previously thought. Central American fires impact US air quality and climate Scientists using NASA satellites and computer models have shown that pollutants from Central American biomass burning can influence air quality and climate in the United States. Tiny airborne particles are a major cause of climate change A scientist at the Weizmann Institute of Science and his colleagues caused a storm in the atmospheric community when they suggested a few years back that tiny airborne particles, known as aerosols, may be one of the main culprits causing climate change - having, on a local scale, an even greater impact than the greenhouse gases effect. People with diabetes more sensitive to cardiovascular effects from air pollution People with diabetes may be at higher risk for cardiovascular problems when air pollution levels are higher, according to a new study of Boston-area residents. The ability of the blood vessels to control blood flow was impaired in adults with diabetes on days with elevated levels of particles from traffic and coal-burning power plants. More Black Carbon News Articles |
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