In the 21st century cities around the world will face increasing pressure on resources and infrastructure from rising populations, urban sprawl and climate change. To ensure cities continue to be the center of global economic activity and happiness cities need to become resilient to all types of shocks both natural and man-made Click & Tweet! , where resilience is defined as the capacity of cities to function, so that the people living and working in cities, survive and thrive no matter what stresses or shocks they encounter.
Cities at risk from climate extremes
With climate change increasing the exposure of cities to extreme weather events and rapid urbanization placing more people and infrastructure in harms cities need to become resilient to floods. Traditionally, cities have built grey infrastructure including dams and levees to manage flood risks. However, this reliance on grey infrastructure has led to severe economic and environmental costs for humans and nature. For example, economically, grey infrastructure is typically capital intensive in building, operating, maintaining and replacing. In addition, as grey infrastructure is mainly built to address a specific water management problem it can amplify risks downstream. Environmentally, grey infrastructure often degrades quality and quantity of water supply leading to ecosystem degradation.
Green infrastructure increasing resilience
To become more resilient to climate change-related extreme weather events, while enhancing nature, many cities for example Copenhagen, Rotterdam and New York are turning to the use of Green Infrastructure solutions that provide equivalent or similar benefits to ‘grey’ infrastructure, but with numerous additional benefits including:
- Economic: Creation of green jobs to install and maintain Green Infrastructure
- Environmental: Improved water quality from pollutants being filtered out
- Social: Improved access to green spaces for physical and recreational activity
Mini case: Rotterdam at risk from climate change
In Rotterdam, heavy rainfall is causing disruption and damage as water floods the streets and cellars of houses while sewer overflows discharge directly into the canals and waterways. With increased temperature from climate change resulting in heavier storm events, Rotterdam is at further risk of flooding: for every one degree increase in temperature, rainfall is projected to increase by 14% increasing the likelihood of flood damage to public areas and buildings as well as disruption to transport.
Rotterdam’s Adaptation Strategy enhancing resilience
Rotterdam’s Climate Initiative (RCI) Adaptation Strategy aims to create a city that is ‘attractive, economically strong and climate proof’. The Strategy has four core parts to it:
- Ensure the city’s urban water system is in good working order through active maintenance and where necessary upgrading of the system to reduce the city’s vulnerability to flooding
- Reduce the pressure on the system by creating Green Infrastructure flood storage spaces and link these to other urban activities, for example an underground water storage facilities doubles as an underground car park. Above ground green roofs, urban vegetation and water squares are used to temporarily store and release very slowly ensuring infrastructure is not damaged
- Encourage and support the participation of all stakeholders in climate change adaptation, for example Rotterdam is promoting the ‘Tile out, Green in’ initiative in which inhabitants are encouraged to replace their paving in their own gardens with plants and vegetation. The purpose of this and other initiatives is to create a shared responsibility between public and private landowners for the collection of excess rainfall
- Add value to the environment, society, economy and ecology through Green Infrastructure adaptation projects. Rotterdam is providing an attractive location for sustainability-focused companies to test innovative environmental technologies, which enhances the local economy and creates green jobs
Green Infrastructure enables cities to become resilient to climate change while enhancing nature.
*Robert C. Brears is the author of Urban Water Security (Wiley). Urban Water Security argues that, with climate change and rapid urbanization, cities need to transition from supply-side to demand-side management to achieve urban water security.