Photo by James Arnott.

While many national governments struggle to take comprehensive action on climate change, major cities around the globe are acting on their own.

The Carbon Disclosure Project (CDP) recently released a report [PDF] tracking initiatives cities are taking to address their greenhouse gas emissions. Many of these municipal governments -- plagued by heat waves and flooding -- recognize the urgent need to mitigate and adapt to climate change.

Cities account for 70 percent of global emissions [PDF] while occupying just 2 percent of dry land. The 53 cities that publicly disclose citywide emissions together produce more than 977 million tonnes of CO2 -- or the equivalent emissions of Germany.