It's no secret that city folk like to eat, shop and travel. But all that consumption adds up to a hefty climate bill.
On the flip side, that means urbanites have a lot of power to rein in greenhouse gas emissions. By changing their diets, their purchasing habits and how they get around, city dwellers can help avert the worst effects of warming.
A new report from C40 Cities -- a coalition of nearly 100 local-level governments committed to addressing climate change -- offers a sweeping plan for city leaders and residents to reduce the emissions associated with their consumption. Along with other urban climate initiatives, these measures would allow C40 cities to achieve 35% of the emissions cuts the world needs from them to meet international targets.
"Cities can do a massive amount," said Tom Bailey, head of research at C40 and a lead author of the report. "It's actually quite a wonderful opportunity."
The reason cities have so much sway is that they are responsible for up to 70% of the greenhouse gases that are pumped into the atmosphere, according to the United Nations.
Some of those emissions come from the tailpipes of cars stuck in traffic and the power plants that keep our iPhones charged. Others are released in distant lands where our shoes, medicines and computers are made.
Until recently, these consumption-related emissions weren't included in most cities' accounting, since they occur outside city limits. Adding them up makes urban carbon footprints even bigger -- and uncovers new avenues for city leaders and residents to combat climate change.
The new report, produced by C40, the consulting firm Arup, and researchers at the University of Leeds in England, focused on cities in the C40 network. They include Los Angeles, San Francisco and New York (former mayor Michael R. Bloomberg is president of C40's board) as well as international hubs like Beijing, Moscow, Dubai and Sao Paolo, Brazil.
Together, consumption in these cities accounts for more than 10% of the world's greenhouse gas emissions.
Cities are increasingly home to the wealthiest people, who tend to consume more, and thus have bigger carbon footprints, Bailey said. By 2050, consumption-related emissions are projected to nearly double as cities grow even bigger and more affluent.