The City of Boulder, Colorado makes history by approving the nation’s first carbon tax.

Voters in a Colorado university town nestled in the foothills of the Rocky Mountains have passed the country’s first municipal carbon tax to fight global warming.

Boulder, Colo., will charge residents and businesses the carbon tax based on how much electricity they use. Most electricity in Boulder is generated at plants that use coal, which produces more of the main greenhouse gas carbon dioxide, than natural gas or oil.