Fewer cars and more bikes. More energy efficiency and green spaces. Cities around the world are setting their own goals, even before world leaders meet in Paris in December to seek an international agreement on climate change.

The  United States and China — the two biggest carbon emitters — have entered into a number of climate agreements, but now mayors from both nations are committing to this growing urban movement.

“We are turning ambitious promises into tangible and specific progress — progress that not only meets national emissions goals, but surpasses them,” said Los Angeles Mayor Eric Garcetti. “As mayors, it’s our mandate to create more livable cities, but it’s our calling to create a more livable world.”

Local officials signed the U.S.-China Climate Leaders Declaration in Los Angeles September 15–16, pledging that their cities will reduce emissions and aim for greater reduction targets than those set by national-level governments.

“We all have to see climate change as a crisis that needs to be acted on today,” said Mayor Ralph Becker of Salt Lake City, Utah, a summit participant.

Salt Lake City limits the time drivers can let their engines idle. Vehicle emissions released while a driver sits with the engine running add to air pollution. (Courtesy of SLC)

Salt Lake City aims for “net zero” city buildings that produce their own renewable energy and for zero waste production in its government buildings.

Responding to the climate change threat “is going to take the political leaders at every level doing more and more,” says California Governor Jerry Brown. Brown’s state is drier than it has been in centuries. The resulting water rationing, agricultural losses and forest fires are all bellwethers of climate change, experts say. “Across the entire specter of civilization, mankind has to rise to this incredible, existential challenge,” Brown concludes.

The Wrightspeed company in California makes electric power trains for commercial trucks that haul and deliver goods. The technology is considered another tool to clean urban air. (© AP Images)