C40 cities network, a network of the world’s megacities committed to addressing climate change, recently published a study investigating the consumption-based greenhouse gas emissions from 79 cities in partnership with the University of Leeds (UK) and the University of New South Wales (Australia). C40’ scope is to generally support cities to collaborate effectively, share knowledge and drive meaningful, measurable and sustainable action on climate change.

This research from C40, released at the IPCC Cities Climate Science conference, has analysed city emissions from a different aspect, looking at the consumption of goods and services including transport, food, clothing and electronics. C40’s new research has revealed that cities have a 60 per cent larger carbon footprint than previously estimated. With greenhouse gases generated by cities being much higher than expected, mayors worldwide have an opportunity to deliver on the Paris Agreement goals.

It was found that almost two-thirds of consumption-based emissions are generated in the supply chains of goods or services that are imported into cities. Whilst the city’s government has little control over these emission sources, they are released because of the city’s demand. The results from this study demonstrated how consumption-based GHG emissions are often significantly larger than those calculated under different methods which focus on emissions within the city borders. Public transport, which includes rail, shipping and aviation, contributes on average 10 per cent to consumption-based GHG emissions across C40 cities.

While cities may not have much direct influence over the carbon intensity of power used in the manufacturing process of an imported product, or whether that product is transported by train or truck, as end users and centres of innovation and change, they do offer many opportunities to transform urban lifestyles into more sustainable ones to help reduce consumption-based GHG emissions. This can be achieved through a combination of resource productivity strategies and consumer policies, targeting carbon intensive consumption categories and lifecycle phases with the highest emissions, and supporting shifts in consumption to goods and services with lower emissions, including through public procurement.

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Many C40 cities are already taking actions that reduce supply chain GHG emissions. To accelerate and scale such efforts, however, greater understanding is needed on how cities can most effectively target transboundary GHG emissions. This will vary between cities, based on, amongst others, their consumption-based GHG emissions profile, governance structure and ability to act.

 

Download the report here

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