By some estimates, the world’s urban cities generate 70 percent or more of the world’s greenhouse gas emissions, because of their concentrations of people, buildings, vehicles, factories, and commerce. Plenty of large cities are trying to curb their emissions—almost two-thirds of select global megacities have climate change action plans, according to one report. But there can be huge differences in emissions among different cities in different countries around the world.
This year, the C40 Climate Leadership Group—a network of global cities dedicated to climate change leadership—collaborated with the U.K.’s Carbon Disclosure Project to survey major cities on their greenhouse gas emissions. The resulting data, though not comprehensive, nevertheless revealed a striking trend: the world’s best-known and wealthiest cities tended to perform worse than megacities in less-prosperous, developing countries.
In particular, well-known places such as London, New York, and Tokyo produced higher levels of emissions, on a per-capita basis, than cities in South America, Asia, and Africa. The top ten cities in the C40 group with the lowest per-capita emissions were led by two in Brazil and included two more in South America and four others spread across Asia. New York City, for instance, produced more than three times the carbon dioxide emissions per person as São Paulo and Rio de Janeiro in Brazil.
This may be because while less-prosperous big cities still benefit from a dense, compact form that has been proven to produce less emissions per person than sprawling development, their residents and businesses may not generate or consume as much energy, from electricity to gasoline.
But these results come with some caveats. A limited number of global cities participated, and their data were self-reported, so their methodologies sometimes differed in measuring emissions from buildings, vehicles, electrical generation, and the like. In fact, there has been no accepted global standard for reporting community-scale greenhouse gas emissions, although several organizations are working on one. Nevertheless, the self-reported city results did generally correspond with a World Bank inventory of greenhouse gas inventories in global cities last year.
The implication for ULI members globally is that more big cities are developing action plans to mitigate climate change, so an ongoing challenge for the real estate industry as well as for government policy makers will be to limit emissions growth in real estate development.
From the C40 group’s survey respondents, here are the top ten global cities with more than 2.5 million residents and the lowest greenhouse gas emissions per capita: