GAO finds no fault with ‘social cost of carbon’

A government probe into the metric used by federal agencies to measure the “social cost of carbon” found no evidence that it was improperly developed, investigators said Monday. 

The Government Accountability Office (GAO) review was requested by a pair of congressional Republicans. The review concluded that a federal working group convened to revise the economic measurement of carbon pollution based its decisions on a consensus of its members’ thinking and relied heavily on peer-reviewed science. 

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The findings were based on interviews with more than 20 members of the panel involved with drafting a document that supported a contentious increase in the metric. That document, though, did not include an independent review of its findings.

“None of the participants we spoke with expressed concerns about how their contributions were incorporated into the final Technical Support Document,” the GAO said. “Many participants confirmed that the working group relied largely on existing academic literature and models to develop its estimates.”

Further, the GAO found, the group took pains to disclose the limitations of its estimates in a document made available to the public. The GAO declined to issue any recommendations to half a dozen agencies and four offices within the White House that worked on the revised social cost of carbon. 

The metric is used in the cost-benefit analyses that agencies are required to perform when drafting new regulation. It is a monetary estimate of how carbon pollution affects health, the environment, rising sea levels and a range of other factors.

Last spring, the White House formally increased the cost from about $21 per metric ton of carbon pollution to $35, effectively increasing the expected net benefits of regulations designed to limit carbon emissions.

The move roiled business groups and congressional Republicans, sparking numerous challenges and a GOP-backed bill that would block the EPA from using the metric in major energy rules.

Sen. David Vitter, the top Republican on the Senate Environment Committee, and Rep. Tim Murphy, chairman of the House Energy and Commerce Committee’s investigative subpanel, were among those who asked the GAO to investigate the matter.

On Monday, Vitter (R-La.) said the GAO report confirmed that the use of the metric is prevalent throughout federal rule-making.

"One thing is clear – the Obama administration is using the social cost of carbon as a de facto carbon tax," Vitter said in a written statement.

"They’re relying on the estimate to justify costly and controversial regulations, and this GAO report confirms its use is widespread and reaffirms concerns over the lack of transparency,” he added.

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