Efforts to reduce black carbon emissions have become an increasingly important component of national and international efforts to fight global warming, particularly as recent studies have concluded that black carbon is the second most powerful climate warming pollutant after carbon dioxide (CO2). Black carbon, a component of particulate matter (PM), is one of four major Short-Lived Climate Pollutants (SLCPs) that live in the atmosphere for a relatively short period of time compared to other greenhouse gases, such as CO2. Because these SLCPs stay in the atmosphere only briefly, reducing their emissions provides benefits almost immediately. The transportation sector is the largest source of anthropogenic (or human-generated) black carbon emissions in Latin America. Within Latin America's transportation sector, diesel engines are the largest source of black carbon emissions.
Reducing Black Carbon Emissions in Latin America with a "Systems Approach" to the Transport Sector
Because black carbon is part of particulate matter, many tactics to reduce diesel particulate matter in Latin America can also reduce black carbon emissions, providing significant local and global human health and environmental benefits. Taken together, these strategies comprise a "systems approach" that has successfully reduced diesel particulate matter and black carbon emissions in the United States, Canada, Europe, and elsewhere. There are three main components of this systems approach:
- Clean fuels: The top priority for Latin America is to ensure widespread adoption of fuel standards that reduce sulfur levels to ultra-low levels (below 50 ppm). Reaching ultra-low sulfur levels will reduce PM emissions from all vehicles and enable the use of advanced vehicle emission control technologies that can eliminate more than 90 percent of black carbon emissions, compared to engines that are not equipped with these technologies.
- Stringent emissions standards for new vehicles: Once ultra-low sulfur fuels are in place, Latin American countries can adopt vehicle emission standards for new vehicles that require the use of diesel particulate filters (DPFs) or comparably effective alternative fuels or advanced vehicle technologies that are emerging in markets around the world (e.g., vehicles powered by natural gas, hybrid-electric or electric power).
- Complementary programs to reduce in-use emissions from existing vehicles: Because so many older, high-emitting vehicles will remain on the road for years to come, countries should consider complementary measures to reduce in-use emissions from their existing diesel fleets. Successful examples of these programs target centrally-fueled urban fleets, with a focus retrofitting the oldest, dirtiest trucks and buses, or providing financial incentives to retire and replace them with newer, cleaner, more fuel-efficient models.
If policy makers follow the systems approach -- relying on proven fuels, technologies and strategies -- black carbon emissions will be significantly reduced in Latin America, providing important climate, public health and other environmental benefits to hundreds of millions of people throughout the region, as well as globally.