BELLINGHAM, Wash. — As a progressive-minded city nestled where the Cascade mountains reach the sea, Bellingham, Wash., has long been looking to scale back its contribution to climate change. In recent years, city leaders have converted the streetlights to low-power LEDs, provided bikes for city employees and made plans to halt the burning of sewage solids.

But while the efforts so far have lowered the city’s emissions, none have come close to erasing its carbon footprint. Now, Bellingham is looking to do something that no other city has yet attempted: adopt a ban on all residential heating by natural gas.

The ambitious plan set for consideration by the City Council in the coming weeks had already prompted vigorous debate over how much one small city should try to do to avert climate catastrophe, at a time when the federal government was putting less emphasis on halting the trajectory of rising temperatures.

“What we’ve got here is a conversation that is taking place in living rooms, in board rooms, in City Councils around the country,” said Michael Lilliquist, a Bellingham council member. “What is the proportionate threat? What is the proportionate response?”