Measuring greenhouse gas emissions is critical to efficient and sustainable management of the systems and structures that make up the world's cities. This spring, the C40 released two major reports that help set a baseline for future climate action. This post originally ran on May 31, 2011

The C40 Cities Climate Leadership Group today released two landmark reports that emphasize the critical role of measurement and transparency in tackling climate change in megacities. The reports demonstrate the current and potential impact of cities confronting climate change, helping cities to focus future activity on areas that will accelerate mitigation and adaptation.

“I firmly believe that if you can’t measure it, you can’t manage it,” said C40 Chair, New York City Mayor Michael R. Bloomberg. “That is true in business and it is true in government. Only by regularly and rigorously measuring and analyzing our efforts can we learn what works, what doesn’t and why, and take effective action.”

Cities are responsible for consuming two‐thirds of the world’s energy. The 58 C40 Cities globally represent 1 in 12 people, 12% of C02 emissions and 21% of GDP. To enable these cities to better measure both current successes and assess future opportunities for action to address climate change, the C40 developed two studies in partnership with two leading organizations in the field, the Carbon Disclosure Project (CDP) and Arup.

The two reports, CDP Cities 2011: Global Report on C40 Cities and Climate Action in Megacities: C40 Cities Baseline and Opportunities, demonstrate the impact cities can have in confronting global climate change. Providing a measurement baseline and a management tool, the studies will enable C40 Cities to set targets, evaluate actions and access resources. The studies will also inform the strategic direction of C40 programs and initiatives, helping the organization to connect cities with similar profiles and agendas.