The Trump administration has been systematically underestimating the damage caused by carbon pollution, slashing figures used under the Obama administration to weigh the impacts of policy, according to a new report from the Government Accountability Office (GAO).

The reduced figure, known as the social cost of carbon, has been used by the Trump administration to justify a host of environmental rollbacks.  

While the Obama administration assessed a $50 per metric ton cost to carbon, the Trump administration uses a $7 per metric ton figure, nixing consideration of any international impacts carbon pollution from the U.S. might have.

“The current federal estimates, based on domestic climate damages, are about 7 times lower than the prior federal estimates,” the GAO wrote in its report.

Numerous government agencies weighing any policy with an environmental angle use the social cost of carbon to calculate the impact of its policies. A lower cost of carbon can make less restrictive environmental regulations appear more favorable. 

Amit Narang, a regulatory policy advocate with Public Citizen, called the changes to the social cost of carbon “crucial to the Trump administration trying to sell its rollback agenda.”

“It’s just a straight chain. You plug in the rigged social cost of carbon that allows EPA to say the costs to polluters is greater than the cost of climate change, and then that's the only way they can make it look like their agenda of rolling back climate change regulations makes sense,” Narang said.

The review was requested by eight Democratic senators shortly after a 2017 executive order from President Trump disbanding a group working to update the methods for determining the social cost of carbon.

"We need a social cost of carbon pegged to the best available science to plan and adapt,” Sen. Sheldon Whitehouse (D-R.I.), who requested the report, said in a release.  

“Instead, the Trump administration undermined the social cost of carbon, and then stuck its head in the sand when the federal government’s top scientists recommended implementing important changes," he added. "Shutting off the headlights of science and sound economics makes it more likely that we’ll drive straight off a climate cliff."

The report comes on the heels of an EPA proposal that would cement the lower social cost of carbon into all future cost-benefit analyses the agency performs.

Narang said the GAO report undermines that proposal, as it favors counting the global impacts of carbon pollution much as numerous other governments already do.

“It makes clear that the social cost of carbon that the Trump administration is using is completely out of step with what the rest of the world and even many states are using,” he said. 

—Updated at 4:36 p.m.