WASHINGTON — A federal report expected to be released Tuesday found the Trump administration set a rock-bottom price on the damages done by greenhouse gas emissions, enabling the government to justify the costs of repealing or weakening dozens of climate change regulations.
The report by the Government Accountability Office, Congress’s nonpartisan investigative arm, said the Trump administration estimated the harm that global warming will cause future generations to be seven times lower than previous federal estimates. Reducing that metric, known as the “social cost of carbon,” has helped the administration massage cost-benefit analyses, particularly for rules that allow power plants and automobiles to emit more planet-warming carbon dioxide.
Critics described the Trump administration’s move as turning a deliberate blind eye to the dangers of climate change. Some critics likened it to President Trump downplaying the risks of the coronavirus, hoping it would “go away” but instead leaving the country unprepared for the pandemic.
“Climate change is a massive threat to our economy. That threat will only grow in years to come, even if we take the action necessary to avoid the worst effects of climate change,” said Senator Sheldon Whitehouse of Rhode Island, one of eight Democrats who requested the review.
The White House did not respond to a request on Monday for comment on the report.
Every ton of carbon dioxide released into the atmosphere imposes a cost on the economy, whether from damage to infrastructure from sea level rise and heat waves or harm to public health. But calculating the price of that damage has been economically challenging and politically contentious.
Conservatives have argued that the valuation serves to make big energy projects look bad and lays the foundation for burdensome and costly industry regulations. Many Republicans said that the Obama administration’s estimates — which in 2016 determined the social cost of carbon to be about $50 a ton by 2020 — were unrealistic and intentionally onerous.
The Trump administration has overhauled not just the regulations governing the economy but also the economic foundations that underpin those regulations. One of President Trump’s earliest moves was to order agencies to unwind Mr. Obama’s climate policies, and with them the social cost of carbon he had set.
When the Trump administration put forward its own rules to regulate emissions from power plants and vehicles, it estimated the cost of climate damages between $1 and $7 per ton of carbon.
The G.A.O. found the administration used two main avenues to push the numbers down. It only factored in damages that would occur within the United States rather than around the globe. It also used an economic calculation, known as the discount rate, in a way that assumes society should not pay much now to prevent harm from climate change to future generations.
“As a result, the current federal estimates, based on domestic climate damages, are about seven times lower than the prior federal estimates that were based on global damages,” the report found.
Michael Greenstone, an economist at the University of Chicago, said the Trump administration’s calculations were not done in good faith.
“It was entirely a political act. I don’t think anyone pretended that those moves were justified,” he said.
Some agencies have defended using the significantly lower figure by saying they are awaiting new federal estimates recommended by the National Academies of Sciences. But the White House disbanded the working group that was devising them and has acknowledged it actually has no plans to update the calculations.
Without them, the G.A.O. found, the federal government “may not be well positioned to ensure agencies’ future regulatory analyses are using the best available science.”
By 2050, under the estimates developed by the Obama administration, the social cost of carbon should be about $82 a ton, the report found. Under the Trump administration’s calculations, the damages would be around $11 a ton.
“This really parallels the mismanagement of coronavirus,” said Michael K. Dorsey, a limited partner with IberSun, a renewable energy company, and a climate expert who has testified before Congress on the social cost of carbon.
“There’s this belief that by doing this you will have some effect of helping the fossil fuel industry,” he said of the administration’s low carbon cost. “The only thing it does, unfortunately, is undermine the ability of the government to make prudent decisions about moving critical resources to communities that are experiencing the unfolding climate crisis.”