By Paul Davies and Andrew Westgate

At the China-US Climate-Smart / Low Carbon Cities Summit held in Beijing on June 7 and 8, 2016 the world’s two largest carbon dioxide emitters announced expanded co-operation in their efforts to counter climate change.

One of the most important results of the summit was the signing of a memorandum of understanding (MOU) between the Compact of Mayors, a global coalition of mayors and city officials pledging to reduce greenhouse gas emissions, and China’s Alliance of Pioneer Peaking Cities (APPC), an alliance established in September 2015 at the inaugural China-US Climate-Smart / Low Carbon Cities Summit in Los Angeles to encourage developed cities to peak their emissions before the national 2030 target established at Paris. A total of 23 APPC member-cities and provinces are now committed to peaking emissions by or before 2030, up from 11 at APPC’s founding in September 2015.  Cities such as Beijing and Guangzhou have even committed to peaking their carbon dioxide emissions by the end of 2020.  According to the World Resources Institute, these 23 cities and provinces represent about 16.8 percent of China’s population and 15.6 percent of China’s carbon dioxide emissions.