Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Black carbon is much larger cause of climate change than previously assessed

Black carbon is the second largest man-made contributor to global warming and its influence on climate has been greatly underestimated, according to the first quantitative and comprehensive analysis of this pollutant’s climate impact..

The direct influence of black carbon, or soot, on warming the climate could be about twice previous estimates, according to an in-depth study published today in the Journal of Geophysical Research-Atmospheres, a publication of the American Geophysical Union.

Accounting for all of the ways black carbon can affect climate, it is believed to have a warming effect of about 1.1 Watts per square meter (W/m2), approximately two-thirds of the effect of the largest man made contributor to global warming – carbon dioxide.

“This study confirms and goes beyond other research that suggested black carbon has a strong warming effect on climate, just ahead of methane,” said co-lead author David Fahey of the U.S. National Oceanic and Atmospheric Administration (NOAA). The study, a four-year, 232-page effort, led by the International Global Atmospheric Chemistry (IGAC) Project, is likely to guide research efforts, climate modeling, and policy for years to come, the authors and other scientists familiar with the paper said..

The report’s best estimate of direct climate influence by black carbon is about a factor of two higher than most previous work. This includes the estimates in the 2007 Intergovernmental Panel on Climate Change (IPCC) Assessment, which were based on the best available evidence and analysis at that time.

Scientists have spent the years since the last IPCC assessment improving estimates, but the new assessment notes that emissions in some regions are probably higher than estimated. This is consistent with other research that also hinted at significant under-estimates in some regions’ black carbon emissions.

The results indicate that there may be a greater potential to curb warming by reducing black carbon emissions than previously thought.

“There are exciting opportunities to cool climate by reducing soot emissions but it is not straightforward,” said co-author Professor Piers Forster from the University of Leeds’s School of Earth and Environment in the United Kingdom. “Reducing emissions from diesel engines and domestic wood and coal fires is a no-brainer, as there are tandem health and climate benefits. If we did everything we could to reduce these emissions we could buy ourselves up to half a degree (Celsius) less warming--or a couple of decades of respite.”.
However, the international team urges caution because the role of black carbon in climate change is complex. “Black carbon influences climate in many ways, both directly and indirectly, and all of these effects must be considered jointly,” says co-lead author Sarah Doherty of the University of Washington in Seattle, an expert in snow measurements.

The dark particles absorb incoming and scattered heat from the sun (called solar radiation), they can promote the formation of clouds that can have either cooling or warming impact, and they can fall on the surface of snow and ice, promoting warming and increasing melting. In addition, many sources of black carbon also emit other particles that provide a cooling effect, counteracting black carbon.
The research team quantified the complexities of black carbon and the impacts of co-emitted pollutants for different sources, taking into account uncertainties in measurements and calculations. The study suggests mitigation of black carbon emissions for climate benefits must consider all emissions from each source and their complex influences on climate.

Based on the scientists’ analyses of these different sources, black carbon emission reductions targeting diesel engines and some types of wood and coal burning in small household burners would have an immediate cooling impact.

Black carbon is a significant cause of the rapid warming in the Northern Hemisphere at mid to high latitudes, including the northern United States, Canada, northern Europe and northern Asia, according to the report. The particles’ impacts can also be felt farther south, inducing changes in rainfall patterns from the Asian Monsoon. Curbing black carbon emissions could therefore have significant impact on reducing regional climate change while having a positive impact on human health by reducing the amount of damage the particles cause to the respiratory and cardiovascular systems.

“Policy makers, like the Climate and Clean Air Coalition, are talking about ways to slow global warming by reducing black carbon emissions,” said co-lead author Tami Bond of the University of Illinois at Urbana-Champaign. “This study shows that this is a viable option for some black carbon sources and since black carbon is short-lived, the impacts would be noticed immediately. Mitigating black carbon is good for curbing short-term climate change, but to really solve the long-term climate problem, carbon dioxide emissions must also be reduced.”

A note from the editors of the Journal of Geophysical Research – Atmospheres, about the significance of this article and the review process the article underwent, is available at

Notes for Journalists
Journalists and public information officers (PIOs) of educational and scientific institutions who have registered with AGU can download a PDF copy of this paper in press.

Or, you may order a copy of the final paper by emailing your request to Kate Ramsayer at Please provide your name, the name of your publication, and your phone number.

Neither the paper nor this press release are under embargo.


“Bounding the role of black carbon in the climate system: A scientific assessment”

Authors (* indicates co-lead authors):
*Tami Bond University of Illinois at Urbana-Champaign, USA;*Sarah Doherty Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, USA;*David Fahey NOAA Earth System Research Laboratory and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, USA.*Piers Forster University of Leeds, United Kingdom;

Contact information for the authors:

Tami Bond, Telephone: +1 (217) 244-5277, Email:

Sarah Doherty, Telephone: +1 (206) 543-6674, Email:

David Fahey, Telephone: +1 (303) 497-5277, Email:

Piers Forster, Email: (or contact Chris Bunting, Press Officer, +44 113 343 2049 or

Kate Ramsayer | American Geophysical Union
Further information:

More articles from Earth Sciences:

nachricht Gas hydrate research: Advanced knowledge and new technologies
23.03.2018 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ

nachricht New technologies and computing power to help strengthen population data
22.03.2018 | University of Southampton

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Space observation with radar to secure Germany's space infrastructure

Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.

The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...

Im Focus: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

New solar solutions for sustainable buildings and cities

23.03.2018 | Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

Latest News

For graphite pellets, just add elbow grease

23.03.2018 | Materials Sciences

Unique communication strategy discovered in stem cell pathway controlling plant growth

23.03.2018 | Agricultural and Forestry Science

Sharpening the X-ray view of the nanocosm

23.03.2018 | Physics and Astronomy

Science & Research
Overview of more VideoLinks >>>