Eighty of the largest cities in the world are working together to reduce greenhouse gas emissions, and the effort seems to be a success.

A new report, Climate Action in Megacities (pdf), says the C40 network of cities (now with 80 members) is expected to cut carbon dioxide emissions by 645 megatonnes by 2020. The reduction would be equivalent to not using 1.5 billion barrels of oil, or nearly 170 coal-fired power plants, ClimateProgress reported. The cities collectively represent more than 600 million people and a quarter of the global economy.

Former New York City Mayor Michael Bloomberg, a UN Special Envoy for Cities and Climate Change, said the network of cities has “really has changed the dialogue” on tackling global warming.

More progress may be on the way. As of last year, 228 cities worldwide, representing 436 million people, had established goals that could reduce CO2 emissions by 13 gigatons over the next 35 years.

“There is still a tremendous amount of action that can be taken,” Seth Schultz, C40’s director of research, measurement and planning, told ClimateProgress. “A lot of the low-hanging fruit hasn’t happened yet. There needs to be more capacity building and more finance.”

-Noel Brinkerhoff

To Learn More:

The Carbon Reduction Efforts of The World’s Major Cities (by Samantha Page, Think Progress)

Climate Action in Megacities (C-40 and Arup) (pdf)

Climate Change Policies Implemented by Cities in U.S. and Around the World Could Save $17 Trillion over 35 Years (by Noel Brinkerhoff and Steve Straehley, AllGov)