HALLOWELL — Gov. Janet Mills forcefully called for action Thursday as she officially launched the Maine Climate Council. The body is tasked by the Legislature with creating a detailed climate change action plan, including a road map to the state’s new commitments to reduce greenhouse gas emissions by 80 percent and to become carbon neutral by midcentury.

“Some people ask: ‘What difference does it make? We’re a small state. We like our old ways. Why can’t things just stay the same?’ ” Mills said. She then quoted 16-year old Swedish climate activist Greta Thunberg’s remarks Monday at the United Nations: “Change is coming whether you like it or not.”

“Thousands of Maine students joined that chorus, and they mean business, too,” Mills said to a standing-room audience of more than 200 people. “They won’t stand for it. It’s their future that’s at stake.”

Gina McCarthy, who served as administrator of the federal Environmental Protection Agency during the Obama administration, praised Maine for creating the council.

“Climate change is always talked about as if it’s this planetary thing, as if it’s something that happens very far away and we have to rely on everyone else to do something,” she said in her keynote remarks. “But this council is a direct reflection of the fact that you think differently about that.

“Nothing innovative starts at the federal level,” said McCarthy, now director of Harvard University’s Center for Climate, Health, and the Global Environment. “Everything starts at the local levels.”

The 39-member Maine Climate Council is charged with developing detailed plans to reduce Maine’s greenhouse gas emissions by 45 percent below 1990 levels by 2030, and by at least 80 percent by 2050 as required by a law passed last session. On Monday, while speaking at the United Nations Climate Action Summit, Mills gave the council another task: Develop a plan to make Maine carbon neutral by 2045.

The council must also develop plans to monitor the effects of ocean acidification, warming ocean temperatures and changes in the salt and dissolved oxygen content of the Gulf of Maine, an expected side effect of warming. It is co-chaired by Hannah Pingree, director of the governor’s Office of Policy Innovation and the Future; and Jerry Reid, commissioner of the Department of Environmental Protection.

At the launch event, officials said the council’s various working committees would meet monthly through next summer to develop strategies. In the summer and fall of 2020 the council will evaluate and prioritize the recommendations and develop an action plan by December, as required by statute.

Members include nine other department commissioners and the leaders of the Maine Center for Disease Control, the Maine State Housing Authority and Efficiency Maine Trust; state legislators Lydia Blume, D-York; Richard Campbell, R-Orrington; Brownie Carson, D-Harpswell; and David Woodsome, R-Waterboro, who sponsored the climate bill; and for the tribes, Maulian Dana, ambassador of the Penobscot Nation.

Other councilors include representatives from labor, nonprofits and the agricultural sector. They include energy manager Benedict Cracolici from papermaker Sappi North America; small businessman Daniel Kleban of Freeport’s Maine Beer Co.; McCain Foods’ environmental controller Jeff Saucier, Executive Director Patrice McCarron of the Maine Lobstermen’s Association; and Patrick Strauch, executive director of the Maine Forest Products Council.

A scientific advisory panel, co-chaired by Ivan Fernandez of the University of Maine Climate Change Institute, includes the council’s other scientist, Andrew Pershing. The chief scientist at the Gulf of Maine Research Institute in Portland, Pershing first drew attention to the fact that the Gulf of Maine is warming faster than any part of the world ocean, save a stretch of a current off northern Japan.

“We’re seeing this transformation of this ecosystem right now from one with a subarctic character to one that resembles a temperate ecosystem,” Pershing told fellow council members and the audience.

Mills was the only U.S. elected official invited to speak Monday before the General Assembly at the U.N. climate summit. She urged world leaders not to delay acting, as Maine is. Her voice, already hoarse before the speech and meetings with counterparts from the European Union and other countries Tuesday, and was slightly strained at Thursday’s climate launch, which she acknowledged at the outset of her remarks.

“I may be a little hoarse,” she said, “but Maine has not lost its voice this week.”