Cutting dirty diesel pollution can reduce global warming while it improves human health

My colleague, Dan Lashof, just posted a great summary of the study, published in Science this week, that explained how cutting soot and smog pollution could help reduce the impacts of global warming in the short-term, while improving human health and buying time for critically important reductions in carbon pollution to take effect over the long term.  The study included a list of 14 key strategies like cleaner diesel engines, improved cookstoves, and capturing methane releases from coal, oil and gas production.

Here’s the key take-away: 

“[T]argeted measures to curb methane, black carbon, and carbon dioxide emissions would yield huge public health and environmental benefits.  Pollution reductions from this strategy would prevent 700,000 to 4.7 million premature deaths each year, increase crop yields, and greatly reduce the risk of extreme climate disruption that lies beyond global warming of 2 degrees Celsius.”

Wow, that’s important news.

NRDC’s work to reduce dirty diesel pollution fits right into these measures.

Experts say that roughly one-quarter of the world’s black carbon comes from dirty diesel engines.  By “dirty diesel,” we mean engines that run on high sulfur fuels and that lack the type of particulate filters that have been standard equipment on U.S. diesel trucks and buses since 2007.

For the past ten years, as regular readers of my posts know, NRDC has partnered with the United Nations Environment Program and a wide range of government, industry, and NGO stakeholders in the Partnership for Clean Fuels and Vehicles.  The Partnership is working in dozens of countries, teaming up with local partners to help governments eliminate leaded gasoline, reduce sulfur levels in diesel fuel, and introduce cleaner vehicles.

By reducing sulfur levels, all diesel vehicles on the road get a bit cleaner, since the cleaner fuel leads directly to cleaner tailpipes. 

But the real benefit is that, once ultra-low levels are reached (50 parts-per-million or less), particulate filters can be used that can eliminate more than 90 percent of the particulate matter that triggers asthma emergencies, cancers, and premature deaths—and that effectively filters out the black carbon emissions that accelerate the impacts of global warming.

We are making good headway, but there is more work ahead.

When the Partnership adopted a global goal of 50 ppm or less for the world’s diesel fuel in 2005, not even the U.S. had ultra-low sulfur diesel fuel nationwide (that would happen in late 2006).  Many countries had sulfur levels of 2,000, 5,000 or even 10,000 ppm.

Today, many countries have adopted our 50 ppm, "ultra-low sulfur" goal as a long-term policy target.  Countries like India and South Africa have reduced their sulfur levels to 500 ppm or below.

But high sulfur levels remain the norm in most developing and transitional nations.

In fact, only a handful of non-OECD countries, including Costa Rica, Chile, Morocco, and Tunisia, have ultra-low sulfur diesel fuel nationwide. You can get this cleaner diesel fuel in Hong Kong, but you can't get it in China unless you are in Beijing or Shanghai.  You can get it in Delhi, Mexico City and a number of other large cities in India and Mexico, but it's almost impossible to find beyond their city limits.

Our goals for the next five years:  just as we worked with our partners in the PCFV to eliminate leaded gasoline, we will now work together to reduce sulfur levels in diesel fuel, and we will work with countries to introduce the particulate filters that cut both particulate matter and black carbon.  

When we started working with the Partnership, we were driven by health concerns of lead in gasoline and diesel particulates in urban air.  Today, we are still compelled by those concerns, but increasingly, we see that this work is also a component of a comprehensive global warming strategy that addresses both the short-term pollutants like black carbon and the long-term, heat-trapping pollutants like carbon dioxide. 

Dan’s post summarizes a very important addition to our knowledge base on the many complementary strategies that will be needed to improve human health and combat global warming around the globe.  I highly recommend you take a look at it—and if you like reading about science, take a look at the study itself.