加州史奎普斯海洋研究院大氣科學家拉曼納森(V. Ramanathan )，以及愛荷華大學化學工程師凱米歇爾(Greg Carmichael)表示，煤煙或其他形式的黑碳，所導致的全球暖化效應程度，約是二氧化碳的6成，其影響程度較二氧化碳以外的其他溫室效應氣體都來的高。
※ 附註：「氣懸膠」原文為aerosol，也有人譯為「氣膠」、「氣溶膠」。如今舊譯「浮質」已幾乎無人使用。「氣懸膠」係指一團氣體與懸浮在其中的微粒，包含固體與液體。粉塵(dust)、煙(smoke)、霧(mist)、煙霧(smog) 與霾(haze) 等都算是其中一種。
Black carbon, particulate matter in the air produced by diesel exhaust, biomass burning, and cooking with solid fuels, has a warming effect in the atmosphere three to four times greater than existing estimates, according to scientists in an upcoming review article in the journal "Nature Geoscience."
Atmospheric scientist V. Ramanathan with the Scripps Institution of Oceanography at University of California-San Diego 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 carbon dioxide, CO2.
The researchers also say that mitigation would have immediate societal benefits in addition to the long-term effect of reducing greenhouse gas emissions.
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 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, a United Nations sponsored agency that periodically synthesizes the body of climate change research.
Ramanathan and Carmichael said the lower, more 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, they said.
The most recent observations have found significant black carbon warming effects at altitudes in the range of 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, air pollution often forms a brownish haze. 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.