Why it’s time to put urban form on the global climate agenda

Urban sprawl may account for up to 30% of global greenhouse gas emissions. That figure might seem high but sprawl demands more roads, parking, more and larger cars, infrastructure, housing and land.

When factoring in emissions from car dependency, embodied carbon in materials, energy use, food waste, and loss of carbon sinks, the number adds up.

The urban world is growing by the equivalent of a New York City every 45 days – while urban land consumption is increasing 67% faster than urban population growth.

Yet urban land use, urban form and design remain largely absent from global climate discussions. For example, not one of the 93 official 2024 United Nations Climate Change Conference (COP29) events featured these topics – though they did have time for sessions dedicated to “space leaders” and “football clubs.”

This is not just an issue of planning – it’s a challenge of imagination. Many still believe growing urban populations require lots of car travel, segregated land uses and more built space per person.

The opposite is true: compact, walkable cities support well-being, opportunity, and far lower emissions. These cities aren’t places of scarcity; they’re places of abundance.

We can align population growth with climate targets by designing cities around people and planet. Per capita emissions in compact, mixed-use cities are typically two to three times lower than national averages.

Countries with similar development levels can have vastly different emissions profiles (US per capita emissions are more than double those of most European countries). The key driver of this difference is urban form.

Low-emissions countries typically have more compact, mixed, multi-modal cities and neighbourhoods – what we call “climate-aligned urbanism.”

Climate-aligned urbanism shapes how we move, consume and live, reducing our environmental impact in five key ways.

Low-density development discourages mass transit and walking or biking. Greater reliance on cars requires more roads and parking, fueling further sprawl.

In climate-aligned urbanism, amenities and services are closer to home and better connected to transportation, enabling more efficient, social and active mobility.

Building single-family houses in suburbia requires more materials and embodied carbon. A typical mid-rise housing unit has 40% less embodied carbon than a single-family home.

And then there’s the embodied carbon in accompanying infrastructure; London’s lower density means its road material stock is three to four times that of Istanbul and Buenos Aires.

Bigger homes negate efficiency gains. A US single-family home uses almost three times more energy than apartments in multi-unit buildings. Sprawl also requires more energy to distribute electricity and water.

Between 1970 and 2010, 60% of urban expansion replaced agricultural land, often the most fertile. Displaced agriculture moves to less productive land, requiring more of it and more inputs like water and fertilizer. Business-as-usual patterns of development threaten 5–8% of our remaining forests.

In wealthy nations, over half of food waste happens at home, driven by large, infrequent purchases. This occurs when suburban residents shop in bulk rather than buying fresh food locally. Higher population densities mean less per-person food waste.

Wherever possible, we must prioritize retrofitting cities, preserving the resources, energy and investments already built into them. Building on undeveloped land (known as “greenfield” development) should be rare but excellent.

Any city can promote infill development, remove restrictions on multi-family housing, lift parking requirements, develop cycling and pedestrian infrastructure and build more homes and commercial clusters close to high-quality transit to move toward climate-aligned urbanism.

In the United States, intelligently addressing America’s chronic housing shortage – building more housing where most people need it – can deliver climate impact similar to the country’s most aspirational transportation decarbonization policy.

The guiding principle that makes climate-aligned urbanism work is attention to the human scale – of how people truly like to live, work and move – and it is already happening worldwide:

Climate-aligned urbanism offers numerous co-benefits, from improved public health to greater economic equity. For instance, walkable urban design alone can boost the likelihood of residents meeting the World Health Organization’s recommended weekly exercise minimum by more than 50%.

Because walking and cycling require little to no investment from users, walkable neighbourhoods provide the equivalent of a $5,000–$10,000 living expense subsidy, freeing up personal income.

Dense, walkable neighbourhoods are also more economically productive per acre, see 1.5 times more spending per visit and have a 35-44% premium on real estate value over auto-oriented alternatives.

Given the lower infrastructure cost per resident in denser neighbourhoods, this higher productivity provides a more sustainable long-term tax base to maintain that infrastructure.

Achieving a better urban form is one of the most powerful things we can do for the climate – and it also means we need to build many fewer clean energy assets to reach net zero.

We will need fewer electric vehicles, solar farms, wind turbines, batteries and land (and have fewer siting and permitting battles), making the energy transition faster, easier and cheaper. This will also mean better health, greater equity and stronger economic development.

Climate-aligned urbanism offers an abundant, positive life – not scarcity – and a blueprint for a just, prosperous and irresistible urban future.

Contributors to the research and writing behind this article include Yuki Numata (RMI), Marissa Maze (RMI), Julia Meisel (RMI), Laurie Stone (RMI), Ben Holland (WRI), Brett Merriam (Gehl) and Wallace Cotton (Gehl).