ROCKLAND, Maine — With Rockland Harbor and the Maine Lobster Festival as backdrops, a group of environmental activists turned out Thursday to voice support for federal regulation of carbon emissions.

About 70 people were at Sandy Beach in Rockland for the rally. The event was timed to precede the expected announcement next week by the U.S. Environmental Protection Agency of what the federal agency has called a Clean Power Plan.

“This is the first ever regulation of carbon pollution in the United States,” said Beth Ahearn, policy director of the Maine Conservation Alliance.

Richard Nelson, a commercial fisherman from Friendship and a member of Maine’s Ocean Acidification Commission, also called for more aggressive federal action on climate change.

The speakers noted that the release of carbon into the atmosphere not only warms the air but the oceans. Ahearn said that 2014 was the hottest year on record and 2015 is expected to exceed that record.

Nelson said that a warming ocean will have a negative effect on the lobster industry. He said warming waters off Long Island have led to a sharp decline in the lobster catch there as the crustaceans head for cooler waters. He said if the ocean continues to warm, the same will happen to Maine.

Ahearn said that the proposed federal regulations will require states to reduce carbon pollution by 30 percent from 2005 levels by 2030. This is aimed at power plants that are the greatest source of carbon emissions, she said.

Maine is well positioned to meet those goals, she said, by its participation in the regional greenhouse gas reduction initiative.

The speakers urged citizens to contact their U.S. senators to support the measure.

Todd Martin, the grassroots outreach coordinator for the Natural Resources Council of Maine, said that the regulations will go into effect unless Congress votes to block them.

Participating in the rally were members of a group called Renew Rockland, which opposes the proposed natural gas-fired power plant that is being considered for Rockland. Member Amy Files said natural gas plants such as this displace renewable power projects.