The study shows that “the same activities that cause most local emissions of urban households – housing and transport – are also responsible for the majority of upstream emissions elsewhere along the supply chain,” said lead author Peter-Paul Pichler from the Potsdam Institute for Climate Impact Research (PIK) in a statement. 

“People often think that mayors cannot do much about climate change since their power is restricted to city limits, but their actions can have far-reaching impacts.”

The climate scientist recommends that instead of using cement and steel for buildings, which take a huge amount of energy – often from fossil fuels – to produce, cities should foster the use of low-carbon construction materials like wood. 

What’s more, raising building insulation standards not only slashes local emissions by reducing heating fuel demand, it also reduces the need for electric cooling in the summer, which in turn cuts power generation and hence greenhouse gas emissions in power plants beyond city borders.

In transport, the scientist points out that expanding public transport networks would minimize local emissions from car traffic and reduce the number of cars on the streets. This would mean building fewer cars elsewhere, lowering the energy load outside urban borders. 

Cities can also choose to power their public transport system using renewable energy. “By choosing energy from solar or wind, city governments could in fact close down far-away coal-fired power plants,” explained Pichler.