The report shows that implementing low-carbon measures in cities would be worth almost US$24 trillion by 2050 and could reduce emissions from cities by 90%. Climate Emergency, Urban Opportunity is the most comprehensive report to date to examine the critical role of national governments in achieving equitable and sustainable economic development in cities, which are home to over half the world’s population and which produce 80% of gross domestic product and three-quarters of carbon emissions.

Science tells us that we need to reach net-zero emissions by mid-century to avoid dangerous climate change. The Urban Opportunity report finds that low-carbon measures in cities could deliver over half of the emission reductions needed to keep global temperature rise below two degrees Celsius. The report shows that it is possible to cut 90% of emissions from cities using currently available technologies and practices – including carbon savings from buildings, transport, materials efficiency and waste – while also delivering a significant economic return. Doing so would require an investment of US$1.8 trillion (approximately 2% of global GDP) per year, which would generate annual returns worth US$2.8 trillion in 2030, and US$7.0 trillion in 2050 based on cost savings alone. Many of these low-carbon measures would pay for themselves in less than five years, including more efficient lighting, electric vehicles, improved freight logistics and solid waste management. With low-carbon innovation we can reach net zero.

The report also demonstrates that in addition to the economic benefits, compact, connected and clean cities provide a higher standard of living and greater opportunity for all. Investments in low-carbon measures in cities could support 87 million jobs annually by 2030. These measures will also reduce choking air pollution, cut chronic traffic congestion, and improve worker productivity. Urban populations are growing fast, and trillions of dollars will be invested in urban infrastructure in the next decade. National governments must seize this brief window of opportunity, as decisions made about cities in the next decade will put countries on a path to prosperity and resilience – or decline and vulnerability.

Low-carbon measures in cities could support the equivalent of:

Cities offer us an unparalleled opportunity to conserve resources and live within our planetary boundaries. Currently, creeping urban sprawl threatens vital agricultural land and forests: between 2000 and 2014, urban settlements expanded by an area of land twice the size of Sri Lanka. Creating more compact, connected cities would protect biodiversity, safeguard food and water security and enhance resilience to new climate hazards – all while cutting emissions from land use change.

The need for a zero-carbon urban transition is immediate, and the costs of inaction could be devastating. Over ten percent of the world’s population, 820 million people, live in coastal zones prone to sea level rise, and 86 percent of them live in urban or quasi-urban areas.

Storm surge and sea level rise are now overwhelmingly urban threats

Many city governments are already playing an active role in tackling the climate crisis: nearly 10,000 cities and local governments have committed to set emissions reduction targets. However, even the largest and most powerful city governments can only deliver a fraction of their mitigation potential on their own: the Urban Opportunity report shows that local governments have direct power over less than 1/3 of the emissions reduction potential in their cities. National and state governments have power over a further 1/3. More than a 1/3 depends on different levels of government working together to cut emissions, making the future of cities a vital collaborative effort.

Proportion of 2050 urban abatement potential over which different levels of government have primary authority or influence.

Launched just ahead of the UN Climate Action Summit, the Urban Opportunity report provides the evidence and confidence that governments need to submit more ambitious Nationally Determined Contributions in 2020, and to propel inclusive, zero-carbon cities to the heart of their national development strategies. Worldwide, fewer than two in five countries have an explicit national strategy for cities, and only seven countries currently have both a National Urban Policy and a Nationally Determined Contribution that specifically address climate mitigation in cities.

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