Greenhouse gas emissions caused by urban households’ purchases of goods and services from beyond city limits are much bigger than previously thought. These upstream emissions may occur anywhere in the world and are roughly equal in size to the total emissions originating from a city’s own territory, a new study shows. This is not bad news but in fact offers local policy-makers more leverage to tackle climate change, the authors argue in view of the UN climate summit COP23 that just started. They calculated the first internationally comparable greenhouse gas footprints for four cities from developed and developing countries: Berlin, New York, Mexico City, and Delhi. Contrary to common beliefs, not consumer goods like computers or sneakers that people buy are most relevant, but housing and transport – sectors that cities can substantially govern.
