{mosads}“It went through a rule-making 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 a formal 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.”