President Trump on Tuesday signed an executive order rolling back steps taken by his predecessor, Barack Obama, to reduce carbon emissions and fight climate change. In particular, Trump ordered the Environmental Protection Agency to begin the process of repealing the Clean Power Plan, an Obama-era regulation that would impose strict new limits on emissions from coal-fired power plants. “My administration is putting an end to the war on coal,” Trump said ahead of the formal signing ceremony.

Trump touted the move as a way to boost economic growth, improve energy security and bring back thousands of jobs in coal country, where voters backed Trump by overwhelming margins in November. Environmental groups countered that the order would do little for the economy while doing potentially irreversible damage to efforts to combat climate change.

In the short term, the new order probably has little practical effect, good or bad. That’s because the Supreme Court temporarily blocked implementation of the Clean Power Plan last year. (Its main provisions weren’t meant to take effect until 2022 in any case.) But assuming that some version of the rule would ultimately have taken effect, Trump’s move could have significant long-term consequences for both the energy industry and the environment. (Trump’s rollback will almost certainly face its own legal challenges.)