From London's bright lights to LA's jammed highways,
no two cities are alike. And the way they go about cutting their
greenhouse gas emissions should be just as unique, a new paper
Cities are responsible for around
75 per cent of the world's carbon dioxide emissions. So if
policymakers are going to keep to internationally-agreed climate
pledges, they're going to have to cut urban emissions.
But there's no one-size-fits-all solution to reducing a city's
emissions, according to a new
paper published in Nature Climate Change today. It looks
at 22 cities across the globe, and tries to work out how climate
policies can be tailored to fit each city's "unique
Some cities are much more polluting than others. To work out how
to design city-specific climate policies, the researchers first
looked at where each city's emissions come from.
The graph below shows the average emissions per person across
the 22 cities the study looked at. Each bar shows how much cities
emit per resident and is separated by the sector the emissions come
from, such as electricity, heating, and transport:
The wealthiest cities tend to have the highest emissions as
their residents generally use more energy, the study finds.
As you can see, big US cities such as Denver, Chicago and Los
Angeles have much higher emissions per resident than than less
wealthy cities in Africa and South America. Likewise, China's
sprawling megacities have much higher emissions per capita than
their neighbours in Southeast Asia.
The paper identifies three factors in particular which affect
each city's emissions: how tightly packed together residents are,
how the city's residents get around, and where each city gets its