The Obama administration used a controversial estimate of the monetary cost of carbon pollution to develop limits for greenhouse gases emissions from new power plants.
The draft rules, released on Friday, were crafted using a “social cost” of carbon metric that some Republicans have worried was developed behind closed doors.
But in acknowledging the use of the estimate on Friday, Environmental Protection Agency (EPA) Administrator Gina McCarthy said that the disputed estimate was developed through normal means that drew from the best science available.
“It went through a rulemaking process twice,” she said on Friday. “It’s in one now. If you’re concerned that we got that number wrong, put some comments in, but the federal government makes its decisions based on peer-reviewed science, whether that’s about health consequences or economic consequences.”
A federal interagency committee in May increased the number that government agencies use to estimate the effect that carbon pollution has on public health, agriculture and other factors. In June, that higher metric was released to the public through an otherwise uncontroversial Energy Department rule on microwave oven efficiency.
Conservatives have registered aformal petition to block that microwave oven rule because it includes the new carbon cost estimate.
When defending the metric on Friday, McCarthy said that the administration did not change the underlying models to develop the metric, just the factors that went into it.
It was always the administration’s plan to review that carbon cost, she said, because “the science is changed.”