A veritable who's who of climate scientists has weighed in on an important question before the Supreme Court: whether the U.S. government should regulate carbon emissions from new cars. Last month, a group of climate scientists told the Supreme Court that a 2003 decision by the Environmental Protection Agency (EPA) not to regulate greenhouse gases from cars was based on a misreading of the scientific literature. Yesterday, eight climatologists took EPA's side in the case, writing that there is "insufficient evidence that carbon dioxide emissions will endanger public health or welfare."
The case, Massachusetts v. EPA, was brought by 12 states and nonprofit organizations who argue that EPA should add greenhouse gases to the list of substances whose impacts on the atmosphere are monitored. The Clean Air Act, first passed in 1970, requires the government to regulate substances that "may reasonably be anticipated to endanger public health or welfare."
In deciding to avoid regulating CO2, EPA relied in part on a 2001 report by a panel of the National Academies' National Research Council. EPA also said that Congress would have specified carbon as a pollutant if it had wanted the agency to regulate such emissions. But climate scientists who sided with the states, including panelist and NASA climate researcher James Hansen, wrote last month that EPA quoted selectively and misleadingly from the report, exaggerating areas of doubt on the issue. Moreover, they concluded, research showed it was "likely" that continual warming caused "risks of adverse impacts on public welfare" including future flooding, worsened storms, and heat waves.
The handful of well-known climate skeptics who support EPA's stance didn't address whether the EPA had correctly cited the NRC report. Instead, their friend-of-the-court brief attacks elements of the study itself, saying that "substantial scientific uncertainties" around climate risks abound. Predicted increases in temperature from climate models are overestimated, wrote the researchers, led by climatologist Patrick Michaels of the Cato Institute in Washington, D.C., who says that excessive carbon inputs into the models are to blame. Forecasted damage from sea-level rise or health risks from heat waves are exaggerated, they added.
The skeptics' brief could create confusion among the nine justices that "works in the government's favor in this case," says Ann Carlson, a law professor at University of California, Los Angeles. She also speculates that the court could accept the government's argument that states don't have standing to sue, a ruling that could forestall future legal attempts to regulate greenhouse gases even if the scientific case for action grows stronger.
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