WASHINGTON — President-elect Donald Trump’s promises to roll back President Barack Obama’s climate change regulations and back out of the Paris Climate Agreement may not have as severe an impact as many environmentalists fear,, a top Energy Department official said Tuesday.

Speaking at a Clean Energy Symposium on carbon capture technology, Deputy Assistant Secretary David Mohler said coal-producing states recognize the environmental and financial importance of curbing harmful emissions and shifting to natural gas, a cleaner form of energy consisting primarily of methane.

During his second term, Obama signed executive orders to curb pollution caused by coal, but the Supreme Court has issued a stay on those regulations and Trump has promised to roll them back.

Even as Trump promises to withdraw from the Paris accord, Mohler said China and European nations continue to meet to discuss ways to curb their emissions. But without American participation it will be much harder to reach the goal of halting the temperature rise at two degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels, he said.

“I worry whether we have to wait for some truly catastrophic event that is irrefutably caused by climate to get us moving,” Mohler said.

The event,, sponsored by the Global Carbon Capture and Storage Institute, was called to highlight non-profit’s annual report on the status of “capture” technology and deployment. But coming a week after the election of a presidential candidate who once declared climate change a hoax perpetuated by the Chinese, experts s focused mostly on politics and what, if any, gains could be made under a Trump presidency.

Members of a panel at the National Press Club took issue with Trump’s promise to return coal-producing states to their former glory, while also l promoting fracking for natural gas. The coal industry is flagging primarily because natural gas is so much cheaper, they said.

“It’s either dumb or deceitful to say go frack and (also say) that you’ll bring coal back.” said former South Carolina Rep. Bob Ingles, a Republican. “You can’t repeal the price of natural gas.

Ingles was one of 30 ex-GOP lawmakers who signed a letter condemning Donald Trump in October.

Adele Morris, a climate and energy economist at the Brookings Institution, said it would make more sense to create a carbon tax to fund revitalization efforts in hard-hit coal communities, rather trying to bring the American coal industry back to its mid-century prosperity.

Panelists expressed doubt that Trump would even be able to fulfill on his two main climate-related campaign promises – to pull back new regulations on burning of fossil fuels and to quit the Paris accord.

Morris said Trump cannot easily withdraw from the Paris agreement — in effect telling  world leaders that climate change is not a serious threat  — without facing consequences. President George W. Bush struggled to forge alliances after 9/11, after he “unsigned” the Kyoto protocol on climate, Morris said.

Dave Armond, executive director of the Clean Air Task Force, which works to prevent the worst effects of climate change, said Trump may not be able to undo the Obama’s environmental regulations.

The regulations, designed to keep 11 million metric tons of carbon dioxide out of the air by 2025, are under review by the liberal leaning U.S. Court of Appeals for the District of Columbia, which should rule early next year. If the court upholds the regulations, Armond said, Trump cannot simply undo them in a day.

Armond compared the post-election situation this year to when Bush replaced President Bill Clinton. Although Bush tried to curtail the EPA’s regulating ability, federal courts repeatedly stopped him.

Judges will not assent to a rapid reversal of federal regulations, Armond said.

“The courts don’t allow a 180-degree arbitrary U-turn. They will require an explanation.” Armond said.  “That will take time.”