The Megacities Carbon Project: measuring urban carbon emissions

Carbon emissions from cities represent the single largest human contribution to climate change. Robust verification of emission changes due to growth or stabilization policies requires that we establish measurement baselines today and begin monitoring representative megacities immediately. An observing system designed to monitor the localized enhancements ("urban domes") of carbon dioxide and methane associated with cities must include a tiered set of surface, airborne, and satellite sensors and a framework for integrating top-down (atmospheric) and bottom-up (activity) data. We present a vision, strategy, requirements, and roadmap for an international effort to assess directly the carbon emission trends of the world's megacities. We describe a new coordinated pilot project for the megacities of Los Angeles and Paris that leverages and extends established measurement infrastructure in those cities and techniques being developed in methodological studies of smaller cities.