President Donald Trump signed an executive order on Tuesday rolling back Obama-era policies to curb planet-warming greenhouse gas emissions, a senior White House official said.

The order, called the “Energy Independence Executive Order,” begins a review of former President Barack Obama’s signature program to deal with climate change, the Clean Power Plan, which limited greenhouse gas emissions from power plants.

Flanked by coal miners and Cabinet members, Trump vowed to spark an “energy revolution” that would put coal miners across the country back to work.

“Today’s energy independence action calls for an immediate re-evaluation of the so-called Clean Power Plan,” he said during a ceremony at the Environmental Protection Agency that lasted less than 30 minutes. “We’re ending the theft of American prosperity and rebuilding our beloved country.”

In a call with reporters on Monday evening, a senior White House official outlined the contents of the order.

“We have a different view about how you should address climate policy in the U.S., and we’re going in a different direction,” the official said. “I can’t get into ultimately what that means from an emissions standpoint. I have no idea.”

The order instructs all agencies to identify all policies that “serve as obstacles or impediments to energy production,” said the official, who spoke on background. The White House provided no timeline for implementing the order, but said that EPA Administrator Scott Pruitt was “ready to hit the ground running.”

The executive order takes other measures to protect the coal industry, such as instructing the Department of the Interior to lift a temporary ban on coal leasing on federal lands that the Obama administration put in place last year. The order scraps federal guidances instructing agencies to factor climate change into policymaking, and to disband a team tasked with calculating the “social cost of carbon.”

REUTERS/Ernest Scheyder A coal-fired power plant in Texas on Jan. 9, 2017.

Undoing The Clean Power Plan

Trump’s executive order will likely kneecap the federal government’s most important policy for reducing carbon emissions. Doing so would also hamper U.S. efforts to meet the commitments made more than a year ago in the 195-country Paris Agreement ― the first global climate deal to include the U.S. and China, the world’s biggest polluters.

The long-expected order gives teeth to Trump’s America First Energy Plan, a vague policy outline he issued after his inauguration to eliminate Obama’s Climate Action Plan.

Obama’s plan, launched in 2013, set a strategy for combating climate change by cutting greenhouse gas emissions from power plants. The utility sector accounts for the greatest portion of the U.S. carbon footprint, producing 30 percent of all emissions, according to 2014 data from the EPA. That’s largely because coal, by far the dirtiest-burning fossil fuel, has long served as the country’s primary source of electricity.

The core of Obama’s initiative was the Clean Power Plan, a sweeping EPA rule that aimed to reduce carbon emissions from existing power plants by 32 percent below 2005 levels. The policy set new standards for new natural gas-burning power plants, and put stricter limits on coal-fired, steam-based plants, forcing them to be fitted with controversial carbon-capture technology. By implementing the plan, the U.S. hoped meet its emissions reduction goals as part of the 2015 Paris climate agreement. (The failure of previous global deals, such as the 1992 Kyoto Protocol, hinged partly on the United States’ refusal to implement emission cuts.)

The president’s elder daughter, Ivanka Trump, and her husband, White House senior adviser Jared Kushner, convinced the president to remove language from his new order that was critical of the Paris accord, according to The Wall Street Journal. It’s unclear how the U.S. can meet its commitments without the Clean Power Plan in place.

Last year, a coalition of Republican-controlled states ― led by Pruitt, who was then Oklahoma’s attorney general ― filed a lawsuit to stop the emissions rules, prompting the Supreme Court to grant a stay suspending implementation. Pruitt launched at least 13 lawsuits against the EPA before he became the agency’s administrator last month.

Yes, you can cut programs and you can go about it with your fiscal authority to try to change policy, but in order to modify regulations, you have to be able to withstand an arbitrary-and-capricious standard. Pete Fontaine, environmental lawyer

Repealing those rules could prove expensive and deadly, costing the U.S. economy up to $600 billion by removing critical incentives to increase energy efficiency, according to the research firm Energy Innovation. The CCP’s repeal could lead to billions of tons of carbon being released into the atmosphere, which in turn could contribute to more than 120,000 premature deaths, according to a writeup of the study in Forbes.

Still, another Supreme Court decision may hinder the Trump administration’s efforts to completely scrap the plan. In 2007’s Massachusetts v. EPA, the court ruled that greenhouse gas emissions constituted pollution, requiring the EPA to take action. Plus, courts work both ways: Environmental groups are widely expected to sue over attempts to stop cutting emissions.

“In order to make policy change, it’s going to need to be supported by the science, and that’s where I think ultimately the effort is going to founder,” Pete Fontaine, a veteran environmental lawyer who worked at the EPA, told The Huffington Post. “Yes, you can cut programs and you can go about it with your fiscal authority to try to change policy, but in order to modify regulations, you have to be able to withstand an arbitrary-and-capricious standard.”

Such standards, which can be used to overturn previous court rulings, would need to stand the test of climate science, Fontaine said.

“Facts will not be changed by people expressing beliefs in an alternative set of facts,” he said. “The science is well settled on climate change, and that science is based on literally more than a century of scientific inquiry and the laws of physics, which are going to govern here no matter what people say is contrary to their beliefs.”

Yet a battle appears to be brewing in the Trump administration over the future of the endangerment clause, policy that spawned from the Supreme Court’s ruling categorizing carbon dioxide and methane emissions as a public health threat. David Schnare, an appointee from the EPA transition team, quit suddenly earlier this month in part because Pruitt refused to take on the clause, Politico reported.

“The backstory to my resignation is extremely complex,” Schnare told E&E News, an energy and environment news wire. “I will be writing about it myself. It is a story not about me, but about a much more interesting set of events involving misuse of federal funds, failure to honor oaths of office, and a lack of loyalty to the president.”

On Monday, the White House official said the Trump administration believed the endangerment clause applied only to auto emissions, not utility sector pollution.

Kristina Barker/Reuters Haul trucks move coal at a mine in Wyoming on June 1, 2016.

King Coal’s Decree

By lifting the temporary moratorium on coal leasing, the Trump administration is ending a policy aimed at lessening the environmental impact of mining and increasing the government’s yield on investment.

The current rules grant coal companies the right to apply to schedule leases at times favorable to them, as well as to design the tracts and control the terms on which they’re offered. Critics say the standards are lopsided, giving coal producers above-market-value cuts of revenue generated from mining.

The government levies an 8 percent cut of revenue from underground mining and takes 12.5 percent from surface mining, which includes environmentally destructive techniques such as mountaintop removal and open pit mining. That money is split between the federal government and the state where the coal is mined.

But Dan Bucks, former director of revenue for the state of Montana, a major coal producer, said the leasing program is “essentially broken,” with more than 90 percent of leases awarded without real competition.

“Lease payments, for those of us who have examined from outside can determine, have failed the market value standard test,” he said. “The American people have been shortchanged on the leasing side as well as the royalty side.”

“The Obama administration wanted to fix that,” added Bucks, who is not aligned with either Democrats or Republicans. “They wanted to update the leasing program so public issues, namely environmental issues and climate change, could be taken into account before leases were offered.”

Trump vowed to resuscitate the coal business by axing environmental rules that he and the industry blame for years of decline and thousands of layoffs. Those promises won him big victories in coal country. But shrinking market demand has actually played a bigger role in coal’s decline.

Cheaper, cleaner-burning natural gas has devoured coal’s share of the electricity market over the past decade. In response, coal companies have bet big on continued demand from China. But Chinese demand peaked in 2012, and has since plummeted due to the country’s slowing economy and a move to suspend the construction of coal-fired power plants in favor of renewable energy.

“We love our coal miners,” Trump said at the signing on Tuesday, correctly noting that coal has been in decline since between Obama took office. “Great people.”

Carlos Barria/Reuters President Donald Trump signs a resolution to nullify the Stream Protection Rule at the White House on Feb. 16, 2017.

A War On Environmental Protections

Trump has put numerous other environmental regulations on the chopping block since his inauguration. He and many Republican lawmakers argue that these rules created unnecessary and at times pricey hurdles for corporations and small businesses.

Earlier this month, the White House proposed slashing the EPA’s budget by nearly one-third, a move that would eliminate popular programs like Energy Star and environmental justice initiatives, and would cripple the agency’s enforcement division. The EPA scrapped a rule earlier this month requiring oil and gas drillers to report leaks of methane, a greenhouse gas 40 times more potent than carbon dioxide.

Last month, after House Republicans voted to overturn a rule protecting waterways from coal mining pollution, Trump signed an order instructing the EPA and Army Corps of Engineers to overhaul the 2015 Waters of the United States rule, which expanded federal control over wetlands and other waterways by 3 percent. The rule essentially provided guidelines on whether anti-pollution laws would apply if, for example, a farmer dams a stream to make a pond for livestock or a developer fills in a marsh to build a new house.

During a call with reporters on Monday, the White House official danced around questions about climate change, at one point admitting he believes manmade global warming is real.

“It’s not a controversial statement, the question is to what extent and over what period of time,” the official said in response to a flurry of questions. “We’re focused on this order for tomorrow.”

He refused to say whether the White House staffers working on the order believe in climate change, insisting the question was irrelevant.

“When it comes to dealing with climate change,” he said,”we want to take our own course and do it in our fashion.”

This story has been updated to include information from a White House call with reporters and details from the March 28 signing event.