Low Carbon Cities: Is Ambitious Action Affordable?

Research has begun to uncover the extent that greenhouse gas emissions can be attributed to cities, as well as the scope for cities to contribute to emissions reduction. But assessments of the economics of urban climate mitigation are lacking, and are currently based on selective case studies or specific sectors. Further analysis is crucial to enable action at the urban level. Here we consider the investment needs associated with 11 clusters of low carbon measures that could be deployed across the world’s urban areas in a way that is consistent with a broader 2°C target. Economic assessment of these low carbon measures finds that they could be deployed around the world with investments of c$1 trillion per year between 2015 and 2050 (equivalent to 1.3% of global GDP in 2014). When the direct savings that emerge from these measures due to avoided energy costs are considered, under the central scenario these investments have a net present value of c$16.6 trillion USD in the period to 2050. However, discount rates, energy prices and rates of technological learning are key to the economic feasibility of climate action, with the NPV of these measures ranging from -$1.1 trillion USD to $65.2 trillion USD under different conditions