Nine states in the region, including Maine, say they will set more aggressive limits on pollution by electricity generation plants.

The Regional Greenhouse Gas Initiative, or RGGI, is a market-based cap-and-trade program that sets limits on carbon-dioxide emissions in participating states. Power generators can buy and sell emission allowances under the program, and it produces revenues that the states largely invest in energy efficiency.

Since 2009, regulated CO2 emissions have dropped by roughly 40 percent. Now the states plan to drive down emissions another 30 percent by 2030.

Environmentalists, such as Dylan Voorhees of the Natural Resources Council of Maine, are applauding the consensus targets reached by governors of both parties.

“We are experiencing a time when the federal government and the White House are withdrawing from leadership on climate change, and this is an example of states stepping up to lead on climate change. And that’s very promising,” Voorhees says. “And very important.”

The new limits are not yet set in stone — there will be a comment period and the issuance of an economic analysis before it’s finalized.

This article appears through a media partnership with Maine Public.