Maine and eight other states that have a regional compact to reduce greenhouse gas emissions have agreed to deeper cuts to carbon emissions over the next decade.

The states participating in the Regional Greenhouse Gas Initiative – known as RGGI – are pledging to cut emissions from power plants by at least 30 percent between 2020 and 2030. That’s slightly higher than the current agreement to reduce emissions by 2.5 percent annually.

A separate provision would allow for even deeper pollution cuts, if they wouldn’t be too costly to states.

The plan – announced Wednesday – is not yet final, and a meeting is set in Baltimore on Sept. 25 to solicit comment from power companies and others affected by the decision.

Environmentalists say such state efforts are especially important since President Trump ’s decision to pull the nation from the global Paris climate pact.

“With the current disastrous policies and rhetoric of the Trump administration, we’re pleased to see these states step up, listen to their constituents, and come together to increase clean energy in the region,” Mark Kresowik of the Sierra Club’s Beyond Coal Campaign said in a statement.

The Conservation Law Foundation, which has pushed to strenghten RGGI as part of its New England for Paris campaign, said the program has created thousands of jobs, saved customers more than $600 million on their energy bills, and prevented thousands of asthma attacks.

“With the Trump administration making every effort to turn back the clock on environmental progress, it falls to state and regional collaboration to lead the way in protecting public health and defending clean air and water,” said the foundation’s attorney, Phelps Turner.

Sarah Jackson, climate and energy policy manager for The Nature Conservancy’s Northeast chapters, also highlighted the threat of climate change.

“We at The Nature Conservancy want to thank the RGGI state governors for recognizing the clear and urgent threat that climate change presents to the people and places we hold dear,” she said in a statement, “and for making this important decision to step up actions to address this global crisis.”

Katie Dykes, a Connecticut regulator who chairs the initiative, said in a statement that the compromise agreement will “secure significant carbon reductions at a reasonable price on into the next decade.”

In addition to Maine, Maryland, Massachusetts and Connecticut, the pact includes Delaware, New Hampshire, New York, Rhode Island and Vermont. New Jersey pulled out of the group in 2011.

The regional initiative, which started in 2009, is a state-driven cap-and-trade system to reduce gas emissions, which contribute to global warming by trapping heat in the atmosphere.

Participating states agree to limit pollution from power plants, and to allow energy producers to bid against each other in auctions for the right to emit carbon. The initiative has raised $2.7 billion from these auctions, money that is being used to fund clean-energy programs, including Efficiency Maine.

Press Herald Staff Writer Tux Turkel contributed to this story.