Low-carbon actions by cities could generate US$16.6 trillion in savings through 2050 and reduce greenhouse gas emissions by 3.7 gigatonnes per year by 2030, according to a working paper released last week by the Global Commission on the Economy and Climate.

“The infrastructure investments made in cities over the next few decades will lock the world into either a higher- or a lower-carbon path,” warned a research team led by Andy Gouldson, co-director of the UK’s Center for Climate Change Economics and Policy. “Policy and financing environments need to shift significantly and quickly if cities are to move towards lower-carbon development paths.”

Cities will account for an anticipated US$62 trillion in GDP, 67 to 76% of global energy use, and 71 to 76% of energy-related greenhouse gas emissions in 2015, the paper notes. By 2030, their combined GDP is expected to rise to US$115 trillion.

The paper lists 11 low-carbon actions for cities in three categories—buildings, transportation, and waste—and provides an economic case for energy efficiency in new and existing buildings, expanded and improved mass transit, cycling promotion, and distributed energy generation. It calls for international cooperation to share knowledge on low-carbon initiatives, build common platforms and standards for municipal action, boost local capacity to execute low-carbon strategies, improve cities’ access to financing for low-carbon infrastructure, and support national governments’ efforts to empower cities.