New Report Confirms Black Carbon Significant to Climate Change: Diesel Engines Best Target

A striking new report was released yesterday showing diesel pollution’s significance in climate change.  In fact, the report shows that black carbon is the second most important individual climate-warming agent after carbon dioxide (CO2) and a much more potent source than previously reported.

Black Carbon (BC) results from the incomplete combustion of fossil fuels, biofuels and biomass. Black carbon absorbs visible light, which disturbs the planet’s radiation balance and leads to increased warming.  Sources of black carbon include diesel engines, cook stoves, brick kilns and open biomass burning.

Scientists have known for more than a decade that black carbon contributes to climate change, but the extent to which it warms, the role from various sources, and the targets and role of mitigation have been unclear. This new report, “Bounding the role of black carbon in the climate system: A scientific assessment,” provides new evidence and clarity that we believe should encourage additional action to reduce this pollution.

Some significant findings from the black carbon study include:

● The direct climate impacts of BC are nearly twice as great as previously believed (2007 IPCC’s Fourth Assessment), ranking BC “as the second most important individual climate-warming agent after carbon dioxide”.

● The study finds that diesel engines are the best target for mitigation, followed by brick kilns and residential stoves, and that cleaning up diesel engines could slow warming immediately.

● Confirmation that BC causes significantly higher warming over the Arctic from a combination of the warming effect on the atmosphere and the additional effect of black carbon darkening snow and accelerating the melting of Arctic snow and ice.

Our partners at the Clean Air Task Force have more details here and here.

We believe the evidence from this report underscores the critical need to continue the fight to reduce diesel pollution. For close to a decade, SACE has advocated for diesel emissions reductions to protect public health, which is still very critical. But, with the growing evidence of the role of black carbon in climate change, it is increasingly important that we focus on a comprehensive, targeted plan to cut emissions from diesel engines and other black carbon sources for the protection of both our health and the climate.

Some of the various actions already undertaken in our region include:

● the retrofitting, replacement and refueling of diesel school buses, trucks and equipment

● the establishment of the Southeast Diesel Collaborative that works to expand knowledge, build connections, and promote solutions to diesel emissions; and

●  the establishment of state clean up programs and numerous idling reduction goals by municipalities, schools and businesses

These have all had a significant role in reducing diesel emissions. However, in recent years, interest and commitment nationally to funding diesel clean up has been waning, with the assumption that fleet turnover is happening and cleaner diesels are now in operation. Unfortunately, the recession caused a steep decline in the turnover rate, leaving many older – often decades older – diesel engines still in operation. Much more action is needed.

We call on large businesses, universities, fleets and other entities that contract or own diesel equipment to commit to only using new or retrofitted diesel equipment and vehicles. Our elected officials also must not back down from support for diesel clean up programs, but rather increase their commitment and funding to existing and new diesel clean programs in the most recent transportation bill, MAP-21, and the Diesel Emissions Reduction Act that have proven their benefits in cutting emissions from this sector, specifically in construction equipment, shipping and across our logistics chains that heavily employ diesel equipment.

Along with our partners in the Diesel Clean Up Campaign, we also recommend reducing the excise tax on new diesel engines to accelerate fleet turnover, creating a model for curbing emissions from aging diesel fleets globally, driving faster global deployment of flaring technologies for natural gas systems to achieve complete combustion of flared gas (another source of black carbon), and working towards greater public-private partnerships and multinational collaboration (e.g. the State Department’s Climate and Clean Air Coalition), which would have positive economic benefits throughout the U.S. economy.

As evidenced from this new study and others, attention to reducing black carbon could play a vital role over the next few years in curtailing the pace of climate change and its resulting impacts. We cannot and should not wait, as we have in addressing carbon dioxide.  Action on these pollutants now can have an immediate impact.

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5 Comments

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Conspicuously absent from this article is any mention of using biodiesel, which is known to reduce particulates by as much as 50%, immediately, with no expensive modifications, processes or engine replacements.

Also, diesel engines by definition are 15+% more efficient than internal combustion engines, and produce far fewer greenhouse gasses than gasoline powered engines do. By virture of their longevity, which is far greater than gas engines, they are greener since they do not need to be replaced (along with the vehicle itself) nearly as often as gas vehicles do. A typical Mercedes-Benz passenger car easily runs 300k miles or more, half a million or more if well cared for. I’ll be interested to see if a Prius or other hybrid can do that well!


Comment by Diesel Driver on January 16, 2013 3:45 pm


Diesel emissions are over 1000 times as toxic as gasoline emissions. The black cloud of smoke from an uncatalyzed poorly tuned Diesel should not be breathed, and if you can even smell it avoid it to the maximum extent possible. All over Asia and the Third World we see millions of Diesel vehicles contributing to this problem, with uncatalyzed and poorly tuned engines pumping out cubic miles of filthy, toxic, carcinogenic waste.

It will take money to help solve this problem. Governments worldwide should license the sale of Diesel fuel, to certify that the engine is running just as clean as possible. China, India, Indonesia, Brazil, Russia, all the large developing economies, we are talking to you!

Natural gas flaring is another activity that should be certified to be as clean as possible. We are damaging our planet in a way that is not difficult to avoid, fouling our own nest as it were. Cook fires worldwide should be cleaned up as well, although this will require a substantial investment in clean wood-burning stoves and ovens.

Although cook fires go back to prehistoric times, there are so many many more than ever before, they are having a negative effect on our planet. Once again, nations worldwide should help their own citizens to live a clean lifestyle.


Comment by Michael Moon on January 16, 2013 3:51 pm


@Diesel Driver, Thanks for your comments. We will get the greatest benefit from reductions from the highest polluting sources, like heavy-duty diesel vehicles (tractor trailer trucks, construction equipment, shipping, etc.). Passenger diesels have a smaller impact. Biodiesel, depending on the source and the blend (ie primarly waste resources such as our fuel http://www.cleanenergybiofuels.com), could certainly provide some benefit as well. The feedstock is critically important, however, if we truly want to gain the benefits from biodiesel.


Comment by Anne Gilliam Blair on January 16, 2013 4:19 pm


@Michael Moon. Thanks for your comments and emphasis on additional mitigation opportunities.


Comment by Anne Gilliam Blair on January 16, 2013 4:20 pm


“Diesel emissions are over 1000 times as toxic as gasoline emissions.” – That sounds pretty dramatic. Sources please? Yes, I’m skeptical of numbers like that.

” The black cloud of smoke from an uncatalyzed poorly tuned Diesel should not be breathed…” Nor should the greenhouse gas laden exhaust from a gas powered car! – Here we go with hyperbole again. What do you say people get more rational, and less emotional about this issue. In my experience, in an area with lots and lots of vehicles on the road at all hours, the sight of any cloud at all coming from a diesel vehicle is *extremely* rare. Far more often, I see large blue clouds being emitted from gasoline engines that should have been retired before their diesel contemporaries are barely broken in at 200,000 miles.

Maybe Mr. Moon has been seeing the opaque, black cloud billowing from a big-rig stack in the photo the Union of “Concerned” Scientists had on their web site in the recent past. To anyone with even the slightest knowledge about engines of any kind, that photo was clearly rigged. Any engine emitting that amount of smoke would not run for more than a few minutes without failure.

Meanwhile, the Archer Daniels Midland lobby continues to receive massive subsidies for making ethanol from a valuable food crop, and expending more energy to make the product than it delivers. How green is that? Don’t get me started on coal-powered “zero-emissions” electric cars.

Yes, diesel passenger cars are in the minority in the U.S. Not for long, now that the Euro smog specs are in line with U.S. rules. How about a durable, reliable car that gets 65mpg? Mini D, and fun to drive.

Somehow the fact that biodiesel can be put into commercial trucks and trains (and jet airplanes, as jet fuel is very similar) has escaped Mr. Moon; validating my observation that too many anti-diesel people are less than informed, and a bit myopic.

Meanwhile, thousands of independent owner-operators are being forced to replace their rigs or engines at the cost of nearly a quarter of a million dollars, or go out of business if they want to continue picking up goods at certain ports. The geniuses who wrote that rule apparently have not heard of biodiesel, and it’s particulate reducing properties.

I’m a treehugger from way back, but in this case, I can see that the anti-diesel do-gooders may be doing more harm than good; and that’s a shame.


Comment by Diesel Driver on January 16, 2013 5:50 pm


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