Green Acton is the local chapter of the Mass Climate Action Network.
From their site at http://www.massclimateaction.org/
The Massachusetts Climate Action Network (MCAN) is a statewide organization that coordinates the work of locally organized groups across Massachusetts fighting the climate crisis. We have a large and vigorous community of 46 chapters (in a fifth of MA communities), hundreds of members, and others who communicate, network, and share information related to climate action.
Massachusetts Climate Action Network