Mounting evidence justifies EPA’s regulation of greenhouse gases

Sixteen prominent climate scientists argue that there is more reason than ever for the Environmental Protection Agency to regulate greenhouse gases, at the same time some politicians are pushing the EPA to reverse its 2009 decision to do so. In a paper appearing in the Dec. 14 issue of the journal Science , these scientists, including Solomon Hsiang, a professor in UC Berkeley's Goldman School of Public Policy, assert that the evidence today that climate change is affecting the health and welfare of Americans is even greater and more conclusive than it was nine years ago, when the EPA, in a landmark "endangerment finding," took on the legal obligation to regulate greenhouse gases under the Clean Air Act. The Clean Air Act requires the EPA to regulate air pollutants when the agency's administrator finds that they "cause, or contribute to, air pollution which may reasonably be anticipated to endanger public health or welfare. In 2007, the Supreme Court confirmed the EPA's authority to make an endangerment finding regarding greenhouse gases, characterizing it as a "scientific judgment” about "whether greenhouse gas emissions contribute to climate change. Yet three months ago, one senior Republican senator said that the administration of President Donald Trump might try to repeal the decision, strengthening efforts to roll back vehicle emissions standards and regulations on carbon emissions in the United States. "When the endangerment finding was issued, the evidence supporting it was extremely compelling,” said Woods Hole Research Center President Philip Duffy, the paper's lead author.