City dwellers around the world are making an outsized contribution to climate change, according to new research released today which suggests 'urban consumption' levels will have to fall dramatically if the world is to limit global warming to 1.5C.

The analysis, conducted by the C40 Cities group, suggests consumption-based emissions from nearly 100 of the world's big cities already represent 10 per cent of global greenhouse gas emissions.

Without action to cut emissions associated with what urban businesses and citizens use, eat, and wear - and minimise emissions from the production and transportation of goods and people - city-driven emissions will almost double by 2050, C40 Cities suggests.

To deliver on a 1.5C temperature goal, urban consumption emissions must fall by at least 50 per cent by 2030, the analysis adds.

"This research clearly demonstrates that changing the way we consume could make a significant contribution to cutting emissions," said Mark Watts, executive director of C40 Cities. "This is a wake-up call for all leaders, business, and citizens to consider both the local and global climate impact of the things they consume, and an opportunity to better engage citizens and businesses in solving the climate emergency."

The research suggests high income urban areas, such as the richer enclaves of London, Paris, and New York, will need to reduce the climate impact of consumption by two-thirds within the next decade, while developing cities will need to quickly establish sustainable consumption habits as they grow.

Much of the work will involve changes to the lifestyle of millions of urban citizens, the report contends. Switching to a plant-based diet and cutting food waste, for example, could reduce consumption-based emissions by up to 37 per cent by 2030.

Meanwhile, consumption-based emissions from clothing and textiles could be slashed by almost 40 per cent if people cut their individual buying habits to just three new items of clothes per year, and emissions from consumer electronics could be cut by 18 per cent if all electrical goods were kept in operation for at least seven years.

Such changes would require buy-in from governments, businesses, and citizens, but could save cash and make cities better places to live by reducing pollution, improving citizen health, and using resources more effectively, C40 Cities argued.

"This report focuses on key actions to reduce consumption-based emissions in C40 cities," said Ben Smith, energy and climate change director at engineering consultancy Arup. "All of us, from city leaders and businesses to individuals, have important roles to play by developing policies, regulations, incentives and promoting behavioural changes. The actions in the report are ambitious and challenging, but bold action is necessary."