The EPA Endangerment Determination

Back in April 2007, in a suit filed by Massachusetts against the US EPA the Supreme Court found that greenhouse gases are air pollutants under the Clean Air Act. The case was brought to force the US EPA to determine whether or not emissions of greenhouse gases from new motor vehicles cause or contribute to air pollution which endanger public health or welfare, or whether the science is too uncertain to make a reasoned decision.

Two years later in April 2009, the EPA Administrator signed a proposed endangerment and a cause or contribute findings for greenhouse gases under the Clean Air Act.  (That links to the draft of 2007 since the final was taken down. EPA held a 60-day public comment period, which ended June 23, 2009. If you will recall at the end of the comment period Alan Carlin and John Davidson of the US EPA’s National Center for Environmental Economics detailed their concerns about the science underpinning the agency's "endangerment finding" for carbon dioxide. The two said the US EPA accepted findings reached by outside groups, including the Intergovernmental Panel on Climate Change and the U.S. Climate Change Science Program, "without a careful and critical examination of their own conclusions and documentation." They raise questions about data that EPA used to develop the proposed finding.

The EPA dismissed these concerns and barred the two from working in this area in the future. The hacked emails from the University of East Anglia's Climate Research Unit (CRU) a collaborator with the U.N.'s Intergovernmental Panel on Climate Change reveals support for the concerns of Alan Carlin and John Davidson who said the EPA accepted findings reached by outside groups, including the Intergovernmental Panel on Climate Change and the U.S. Climate Change Science Program, "without a careful and critical examination of their own conclusions and documentation." More importantly, the US EPA is required to make its own evaluation of the underlying science not depend on the findings of others for its Endangerment Determination and must that greenhouse gases are harmful to human health.

Though these days when you say greenhouse gasses most people think carbon dioxide, the main greenhouse substances in the earth's atmosphere are water vapor and clouds. Carbon dioxide represents less than 0.04% (386 parts per million) of the atmosphere and its increase over the past hundred years or so is no doubt due to man’s impact on earth. The other greenhouse gasses are methane (1.8 parts per million), nitrous oxide (0.3 parts per million), hydrofluocarbons (0.00025 parts per million), Perfluorocarbons (0.00086 parts per million), and sulfur hexafloride (0.000006 parts per million). Ozone is also a greenhouse gas, but is not part of the endangerment finding.

On December 7, 2009, EPA Administrator Jackson signed two distinct findings regarding greenhouse gases under section 202(a) of the Clean Air Act:
Endangerment Finding:

The Administrator finds that the current and projected concentrations of the six
key well-mixed greenhouse gases--carbon dioxide (CO2), methane (CH4), nitrous
oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur
hexafluoride (SF6)--in the atmosphere threaten the public health and welfare of
current and future generations.

Cause or Contribute Finding:

The Administrator finds that the combined emissions of these well-mixed
greenhouse gases from new motor vehicles and new motor vehicle engines
contribute to the greenhouse gas pollution which threatens public health and
welfare.

Administrator Jackson explained her decision "relied on decades of sound, peer-reviewed, extensively evaluated scientific data." The declaration has been expected for months, after the Obama administration said earlier this year that it would act on a 2007 Supreme Court decision that found carbon dioxide and five other so-called greenhouse gases are pollutants covered by the Clean Air Act. To use that law to regulate greenhouse gases, the EPA has to prove those gases are harmful to human health. As Kim Strassel or the Wall Street Journal points out, The EPA must prove first that carbon dioxide will cause global warming and that a warmer earth will cause Americans injury or death. Given that most climate scientists admit that a warmer earth could provide "net benefits" to the West, this may not be possible to demonstrate.

Although the EPA could have delayed until March the announcement of findings, in picking this time the administration chose to signal the US’s dismissal of any questions raised by the disclosure of emails hack from the University of East Anglia's Climate Research Unit (CRU) a collaborator with the U.N.'s Intergovernmental Panel on Climate Change. Though the emails released appear to reveal some researchers willingness to suppress or massage data and rig the peer-review process and control the publication of scholarly work, the Administration has dismissed any questions raised as a the “couple of naysayers,” deniers and dismissed them out of hand. The emails do raise new questions about how honest the peer-review process was. The Administration chose the first day of the United Nations global warming conference in Copenhagen as a way to signal full US acceptance of the U.N.'s Intergovernmental Panel on Climate Change determinations and that President Obama wants to demonstrate to other nations that the U.S. is committed to cut its greenhouse gas emissions either through legislation or regulation.