President Donald Trump on Tuesday abandoned former President Barack Obama's policies to reduce greenhouse gas emissions — a move Maryland Democrats pledged to challenge in court and on Capitol Hill as a threat to public health and the climate.
Trump's executive order suspends, rescinds or flags for review half a dozen Obama-era measures that the new administration argues unfairly hurt those who make their living off oil, coal and gas energy.
"That is what this is all about: bringing back our jobs, bringing back our dreams and making America wealthy again," said Trump, flanked by coal miners in a ceremony at Environmental Protection Agency headquarters.
Opponents say the decision will hamper efforts to make the air healthier to breathe and to slow the effects of global warming.
Maryland Attorney General Brian Frosh joined law enforcement officials across the country in promising to oppose in court Trump actions that "ignore both the law and the critical importance of confronting the very real threat of climate change."
Among measures to be reversed is a plan to reduce power plant emissions — seen as key in helping states like Maryland cut the amount of smog that blows in from other states.
Maryland Environment Secretary Ben Grumbles said Trump's decision could make it harder for the state to meet greenhouse gas goals the General Assembly tightened last year, to a target of 40 percent reductions by 2030.
In a statement, he said Republican Gov. Larry Hogan's administration "will continue to focus on energy and environmental actions ... that are critical to our clean air and climate change goals."
U.S. Sen. Chris Van Hollen, a Maryland Democrat, said he would introduce legislation to counter Trump's action with a "cap-and-dividend plan" that "puts a price on carbon pollution and returns the proceeds directly to the American people."
"Climate change is a real and intensifying threat to this country and all of humanity, and any action that undercuts the progress we have made to address its damage is patently short-sighted and fundamentally unwise," said Sen. Ben Cardin, also a Maryland Democrat.
Trump, a Republican, has called global warming a "hoax" invented by the Chinese, and has criticized Obama's power-plant rule as an attack on American workers and the struggling U.S. coal industry. The Clean Power Plan regulations would have restricted greenhouse gas emissions at coal-fired plants, but has long been challenged in court by the energy industry and by Republican-led states, including Oklahoma, the home of new EPA chief Scott Pruitt.
Environmental advocates said the Obama plan was needed to hold other states responsible for the same pollution reductions required by Maryland and others across the Northeast.
Maryland officials estimate that 70 percent of ozone pollution in the state blows in from the west, and last year petitioned EPA to crack down on 19 coal plants in five other states.
"It's a really critical piece," David Smedick, the Maryland representative for the Sierra Club's Beyond Coal campaign, said of the Obama policy.
There are eight coal-fired power plants in Maryland, including the C.P. Crane plant in Bowleys Quarters and the Brandon Shores and H.A. Wagner plants near Glen Burnie. They must adhere to state clean-air laws and to the Regional Greenhouse Gas Initiative, an agreement that cuts power plant emissions across the Northeast.
Those plants' owners did not respond to requests for comment.
Supporters of Trump's order said it will provide regulatory relief and promote domestic energy security.
"The Clean Power Plan is a classic example of over-reach by a federal agency," Rep. Andy Harris, Maryland's only Republican in Congress, said in a statement. "This executive order will restore economic vitality stamped out by the Obama administration, and return power over energy production to the states."
U.S. Chamber of Commerce President Thomas J. Donohue called the order "a welcome departure from the previous administration's strategy of making energy more expensive through costly, job-killing regulations that choked our economy."
In addition to pulling back from the Clean Power Plan, the administration will also lift a 14-month-old moratorium on new coal leases on federal lands.
The Obama administration had imposed a three-year moratorium on new federal coal leases in January 2016, arguing the $1 billion-a-year program must be modernized to ensure a fair financial return to taxpayers and address climate change.
Trump's order will also chip away at other regulations, including scrapping language that requires federal agencies to account for the "social cost" of greenhouse gases, such as the impacts on climate and health. It will initiate a review of efforts to reduce the emission of methane during oil and natural gas production as well as to regulate hydraulic fracturing, which Hogan and Maryland legislators have pledged to ban.
Trump also rescinded Obama executive orders and memoranda that addressed climate change and national security and that sought to prepare the country for the impacts of climate change.
Much of the Obama policies were crafted in an effort to meet the Paris Agreement on climate change, a pact adopted in 2015 that seeks to limit global warming to 2 degrees Celsius, or 3.6 degrees Fahrenheit.
Trump administration officials say they are still in discussion about whether the president will withdraw the country from the agreement.
While Republicans have blamed Obama-era environmental regulations for the loss of coal jobs, federal data shows that U.S. mines have been shedding jobs for decades under presidents from both parties as a result of increasing automation and competition from natural gas, which has become more abundant through hydraulic fracturing. Another factor is the plummeting cost of solar panels and wind turbines, which now can produce emissions-free electricity cheaper than burning coal.
According to an Energy Department analysis released in January, coal mining now accounts for fewer than 75,000 U.S. jobs. By contrast, renewable energy — including wind, solar and biofuels — now accounts for more than 650,000 U.S. jobs.
Baltimore Sun reporter John Fritze and the Associated Press contributed to this article.