Thank you, Senator Carper, for calling this hearing today. It provides an opportunity to tout the successes of one of the few EPA-administered programs that has strong bipartisan support: the Diesel Emissions Reduction Act (DERA), a voluntary grant and loan program designed to reduce domestic diesel emissions. DERA was first passed as part of the Energy Policy Act of 2005 and was reauthorized in 2010. Immediately after Congress's reauthorization, President Obama stripped the program's funding from his budget for the upcoming fiscal year, making a clear statement of his Administration's belief that it was no longer a priority.
DERA has been a successful voluntary program that has achieved reductions in black carbon in the United States without significant negative implementation costs to the regulators or the regulated community. Recent changes in emission standards, the retrofitting of out-of-date engines, and the eventual turnover of older vehicles are expected to reduce the total amount of black carbon emissions by 86% by 2030. As a country, we have already achieved significant reductions with federal regulations and the cost-effective solutions at hand, such as diesel particulate filters: the United States now represents only 8% of global black carbon emissions. The success of DERA and the drastic decrease in domestic emissions have led to similar legislation being introduced abroad.
Many people today will discuss black carbon as a "proven warming agent." It is prudent to not forget the rest of the story: that black carbon is co-emitted with other pollutants, such as organic carbon, that have a cooling effect on the atmosphere. Climate effects of black carbon include cloud interactions, which are not well-quantified and may cause either warming or cooling. Also, collectively, aerosols - of which black carbon is one - are widely understood to have a cooling effect on a global average basis. Clearly, there is a proven need for a more comprehensive evaluation of both the magnitude of particular global and regional climate effects due to black carbon.
As the effects of black carbon are regional in nature, the developing world's emissions do not significantly impact the United States' public health concerns. China and India comprise 80% of worldwide emissions, meaning any domestic controls would have minimal impact on global emissions levels. Any attempt to mitigate black carbon at the global scale will depend on application of a variety of strategies rather than widespread adoption of a single strategy, and, as of right now, there are too many questions and uncertainties surrounding the element to move forward.
EPA has acknowledged there is not enough information currently available about the impacts of black carbon on public health and the climate. Earlier this year, in the final PM NAAQS rule, EPA disagreed with the claim that the Agency should "pursue black carbon reductions for purposes of reducing the impacts of climate change on public health." The Agency and Congress must have more certainty regarding the relative importance of its impacts, as well as commitments from the countries that are the largest emitters, before we even begin discussing black carbon regulation.