Resilient Cities: How Can Cities Adapt for Climate Change Effects?

Globally we are seeing the catastrophic effects of climate change. With more frequent, more severe and previously unforeseen events, such as wildfires, hurricanes, flooding and drought, the need for resilient cities, and in particular infrastructure to be redesigned and/or rebuilt for climate resilience, could not be more apparent.

What is a Resilient City?

According to the OECD, Resilient cities are cities that have the ability to absorb, recover and prepare for future shocks (economic, environmental, social & institutional). Resilient cities promote sustainable development, well-being and inclusive growth.

Resilient Cities are often considered the next chapter in sustainability. With energy and water conservation, we need to be doing more to ensure our cities and structures can withstand a climate event.

Preparation, Adaptation, Recovery

Why do we need them?

It has been projected by the United Nations that by 2050, 70% of the global population will live in cities. With 60% of new urban settlements yet to be built, there is a huge opportunity for building resilient cities.

According to The World Bank, $4.2 trillion could be saved by investing in more resilient infrastructure. With The United Nations Human Settlement Programme forecasting that by 2030, without significant investment to make cities more resilient, natural disasters may cost cities worldwide $314 billion per year and climate change may push up to 77 million more urban residents to poverty. 

These are startling figures.

With the building industry responsible for 40% of global carbon emissions – we have an undeniable responsibility to reduce our impact on climate change and pursue sustainable and climate-resilient construction to create, build and shape our cities into resilient cities. 

The United Nations’ 2030 Agenda for Sustainable Development (SDGs) outlines the need for resilient cities in a number of its targets, both explicitly and implicitly:

• By 2030, “to build the resilience of the poor and those in vulnerable situations, and reduce their exposure and vulnerability to climate-related extreme events and other economic, social and environmental shocks and disasters” (Target 1.5, United Nations 2030 SDG)

• “To make cities and human settlements inclusive, safe, resilient, and sustainable” (Target 11, United Nations 2030 SDG)

• “To strengthen resilience and adaptive capacity to climate-related hazards and natural disasters” (Target 13, United Nations SDG)

Climate Resilient Construction

Climate resilience takes into account both acute events (heat waves, heavy downpours, hurricanes, or wildfires) and chronic events (rising sea levels, worsening air quality, and population migration). Climate resilient construction involves designing, engineering and building infrastructre that can withstand these acute and chronic events. It could mean passive ventilation to prevent overheating, expanded water storage, off-grid back-up power or mitigation of flood risks to name just a few.

It is generally considered that very few cities are currently equipped to deal with more frequent extreme weather events. There are some cities that have taken proactive measures to adapt their cities to protect against the effects of the climate crisis.

Barcelona, Greater Manchester, Helsingborg and Milan were unveiled in November 2021 by the Making Cities Resilient 2030 initiative as the first four European cities recognised as “Resilience Hubs” for their policy and advocacy work in addressing growing climate and disaster risks.

Perhaps one of the most significant climate impacts on and of the urban built environment is the urban heat island (UHI) effect which essentially amplifies global warming, with temperatures rising significantly in cities. UHI is caused by the high thermal capacity (heat absorption) of concrete, asphalt and other dark coloured materials in the built environment.

Some cities are designing infrastructure to specifically combat UHI: Copenhagen, Denmark (which has pledged to become the first city to go fully carbon neutral by 2025, despite a growing population) is cooling the city with seawater from the harbour; Four cities in Poland are using rainwater to combat the UHI effect with Green Bus Stops; Urban green spaces and green roofs can be seen in a number of cities such as Fukuoka, Japan and Paris, France.

Around the world, we can see many examples of how resilence can be embeeded at the core of design and construction:

• The Philippines has adopted dome-shaped roofs to withstand strong winds and typhoons. Strong winds can also be combatted with slopes with multiple roofs, central shafts to reduce wind force and pressure to the roof by sucking in air from outside, and using frangible architecture to prevent structural damage.

• In China, the Sponge Cities Project is piloting eco-engineering solutions to absorb and reuse rainwater in over 30 metropolises to reduce flooding risks.

• Miami is raising street levels and developing green infrastructure.

• Bangladesh has a buoyant multi-purpose building that would rest on pillars with buoyant tanks that raise it during floods.

• To adapt to cold and temperate climates, water walls can be used instead of concrete. Water walls contain drums of water to store heat and provide thermal mass and quicker heat exchange than concrete or masonry.

We can look to these examples, and many moe, as models for how we can potentially modify and strengthen our built environments, and protect urban centers from the effects of a warming planet.