This bill prohibits a person from engaging in any activity that constitutes or involves geoengineering. "Geoengineering" is defined in the bill as any intentional, large-scale intervention in Earth's natural systems and includes stratospheric aerosol injection; weather modification techniques; excessive electromagnetic, radio frequency or microwave radiation emissions; harmful nuclear, biological or chemical emissions; or other polluting atmospheric activity. The Department of Environmental Protection is charged with enforcing the prohibition, and a person that violates the prohibition commits a Class C crime and is subject to a fine of $500,000 for each day the violation continues and any other applicable penalties under the Maine Revised Statutes, Title 38 or other provision of law or rule.