The Trump Administration and the Environment - Heed the Science.

Science-based policies and regulations have resulted in tremendous gains in environmental quality and reduced the population’s exposure to harmful pollutants (Fig. 1). In the United States, the gains have been driven by major laws that were passed and amended by Republican and Democratic administrations alike (Table 1). For example, the 1970 Clean Air Act (CAA), signed by President Richard Nixon, called for a broad array of measures to improve air quality, addressing the major airborne pollutants and their sources. The resulting improvements in air quality have been substantial (Figs. 1 and 2) and have benefited human health.1-3 Nationally, laws covering the environment are implemented and enforced by several federal agencies, including the Environmental Protection Agency (EPA), which has a leading role on the environment, and through partnership with and delegation to the states. When first implemented, the laws and agency actions were based on a “command and control approach” driven by public demands to clean up visibly polluted air, water, and soil. Detection of additional chemical contaminants in air, water, and biota and scientific evidence of adverse health outcomes led to “risk assessment and management” as an additional approach to environmental control. The EPA has also faced general challenges that transcend particular legislation, including a mandate for “environmental justice” to eliminate disparities in environmental exposures4; climate change, which was initially recognized as a problem by the Reagan administration; and other local and global sustainability issues resulting from a growing world population living in mega-cities on a limited land mass. Climate change also provides a case study of the need for integrating the EPA’s science with legal processes, since litigation has become a common tactic for both motivating and blocking regulatory actions. Greenhouse-gas emissions were not directly covered in the CAA, but in Massachusetts vs. EPA, the Supreme Court found that that law was sufficiently broad to cover such emissions from mobile sources.5 President Barack Obama’s Clean Power Plan, currently stayed by the Supreme Court, drew on the CAA to address carbon emissions from power plants.6 States’ actions have also contributed to improving environmental quality. The California Air Resources Board implemented particularly stringent health-based standards for vehicle emissions, which fostered technological advances now in use worldwide. New Jersey’s efforts to clean up hazardous-waste sites and require reporting of toxic