Planning's importance in meeting the challenges of climate change in our cities should not be underestimated, writes Hélène Chartier.

The best climate activist is a good urban planner. Unlike buildings, transport or waste management, urban planning is not an emissions sector per se – therefore, when reporting greenhouse gas (GHG) emissions and climate actions, local and national governments rarely share information on their land-use policies. However, evidence shows that adjusting how we plan our cities and towns will define how we face the climate crisis.

The latest report of the IPCC panel – the United Nations body bringing together the world's leading scientists on climate change – highlights the importance of urban planning. It states that adopting land-use policies leading to more compact and resource-efficient urban growth through higher residential and job densities, mixed land use and transit-oriented development could reduce GHG emissions by 25 per cent by 2050.

Revising land-use policies is the most impactful action that local governments can take to reduce emissions

For this reason, good urban planners are key climate activists. They are taking global action by adopting new approaches that lower emissions and better prepare our cities for climate risks, such as flooding, heat and fire – all of which will worsen in the coming decades.

In North America, city planners are tackling building and transport emissions by limiting car dependency and reducing the size of housing units, which in turn limits the energy use of buildings. Portland is one of the pioneer cities on this agenda. When Oregon's legislature drew an urban growth boundary to Portland's metropolitan area, the city reversed single-family zoning and is developing infill housing projects to promote densification and the production of smaller housing units.

These are not only efficient climate actions–a recent study from Berkeley University has shown that revising land-use policies is the most impactful action that local governments in North America can take to reduce emissions – but also a way to address the housing crisis. With these measures, Portland expects to increase 20 per of its annual housing production and reduce the median rent by 12 per cent.

The City of Vancouver is also paving the way to reverse the 20th-century urban model – known as "modern urbanism" – that has resulted in the growth of sprawling urban areas with disconnected, single-purpose neighbourhoods. Vancouver has recently adopted a new Vancouver Plan that promotes walkable, complete neighbourhoods throughout the city, echoing the model of polycentric cities that the American-Canadian urbanist, Jane Jacobs, presented in her book The Death and Life of Great American Cities in 1961.

The plan provides a gentle densification and diversification of low-density residential areas by including more housing options as well as new amenities, services and flexible workspaces; and by developing a network of green corridors for active modes of travel across the city.

To support this effort to densify and revitalise the city's neighbourhoods, Vancouver also created an innovative "empty home tax" that has reduced vacant properties by 22 per cent since 2017 and has generated revenue to support infill development and affordable housing initiatives.

Urban sprawl and car-oriented planning are not unique to North America

It is important to note that urban sprawl and car-oriented planning are not unique to North America. Other regions, including Europe, face similar challenges. In France, 56 per cent of the housing stock is made up of individual houses, a trend that has been increasing since the Covid-19 crisis. A recent national law called Zero Land Artificialisation, attempts to reduce urban sprawl by 50 per cent by 2030 and achieve net-zero emissions by 2050.

Another priority for urban planners is to prepare cities for extreme heat. The increase in green spaces and permeable soils and the use of trees to extend shade areas have proven to counter urban heat islands effectively. Many cities, especially in Europe, are adjusting their land-use policies to incorporate these tactics.

The forthcoming masterplan of Paris requires new development or major regeneration projects to provide a minimum percentage of permeable surfaces and green space and to compensate for the unavoidable felling of trees; it also creates a "plant deficit" zone where these requirements are increased.

Similarly, Barcelona encourages the use of green roofs by applying a minimum "vegetation rate" for buildings and by subsidising 75 per cent of the cost of new green roof projects. Many European cities also now require new buildings to be constructed with consideration for heat comfort. The London Plan, which is the spatial development strategy for the city, sets out that major development proposals should demonstrate how they will reduce the potential for internal overheating and reliance on air-condition systems.

In Global South cities, urban planners are also accelerating the adoption of land use policies to limit the dramatic effects of the climate crisis. This is critical, as according to the World Bank 90 per cent of the urban expansion in Global South cities happens near extreme hazard-prone areas such as wetlands and other flood-prone areas.

Many cities, especially in south and west Asia and Africa, face the dual challenges of strong population growth and extreme climate risks. Examples of climate-responsive land-use policies include construction restrictions in areas exposed to coastal flooding. Durban created a 94,000-hectare spatial layer wherein development may not occur without obtaining environmental authorisation.

Urban planning is a cross-cutting enabler of emissions reductions and increased resilience

To limit flooding risk, Indian cities such as Chennai are integrating mandatory policies in their masterplans for the installation of rainwater harvesting for all buildings in flood-prone areas. Climate risks are not limited to floods and heat – interrelated risks such as landslides and fires must also be considered. To combat this, Cape Town's new Spatial Development Framework requires buffers to be created between developed and naturally vegetated areas within fire-risk zones.

There are many more examples beyond those shared here that demonstrate the critical and multifaceted role of urban planners in tackling the climate crisis. Urban planning is indeed a cross-cutting enabler of emissions reductions and increased resilience. It is also a powerful way for local governments to mainstream their climate priorities, and to transpose them into legally binding policies.

Hélène Chartier is director of urban planning and design at C40 Cities.

The photo, showing the Îlot Fertile neighbourhood in Paris designed by TVK, is by Julien Hourcade.

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