A Federal program to reduce pollutants that cause environmentally damaging acid rain has been remarkably successful, resulting in improved ecosystem health and providing human health benefits at a fraction of the predicted cost. That's the conclusion of a new report—National Acid Precipitation Assessment Program Report to Congress: An Integrated Assessment—released today by OSTP.
The National Acid Precipitation Assessment Program (NAPAP) is a Federal interagency program that coordinates acid rain research and reports to Congress on the effects of acid rain on sensitive ecosystems and progress towards minimizing those impacts. The new report concludes that the Acid Rain Program—created by bipartisan mandate under Title IV of the 1990 Clean Air Act Amendments—has not only successfully reduced emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) from power plants, but also far exceeded its emissions-reduction goals. A creative, market-based cap-and-trade approach has been critical to the success of the SO2 emissions-reductions efforts. The approach, which combines the best of American science, government action, and innovation, significantly reduced compliance costs by giving utilities flexibility in how they achieved SO2 emissions reductions.
Acid rain is formed when air pollutants like SO2 and NOx react with water and other compounds in the atmosphere. A large percentage of SO2 and NOx emissions come from man-made sources such as electric power generation. Decades of science has shown that acid rain can damage lakes, streams, and forests; degrade air quality; impair visibility; and negatively affect human health. Since its formation in 1995, the Acid Rain Program has worked to protect Americans from these harmful effects by gradually reducing SO2 and NOX emissions from power plants.
In this latest report, numbers tell the story of the Acid Rain Program’s success. U.S. SO2 emissions, for example, decreased by 64% between 1990 and 2009 to a level substantially below the 8.95 million ton statutory limit set by Congress. NOx emissions in the United States decreased by 67% between 1995 and 2009—exceeding the goal set by Congress by more than three-fold.
The estimated cost of complying with Title IV (approximately $3 billion per year) has amounted to a fraction of initial estimates, and the benefits have been enormous, including benefits to human health and the environment. The report concludes that the innovative cap-and-trade system used to reduce SO2 under Title IV was key to achieving these benefits economically.
While the NAPAP report presents evidence of significant improvement, it also points to recent science that suggests that many sensitive ecosystems will be unable to fully recover from the effects of acid rain. Further emissions reductions from additional sources will be necessary to protect these sensitive ecosystems. The report notes that additional reductions projected to occur under the Cross-State Air Pollution Rule, finalized by the U.S. Environmental Protection Agency in July 2011, would reduce the number of lakes being harmed by acid rain by more than half relative to current levels.
Becky Fried is a Policy Analyst at OSTP