Urban Rewilding and Reducing Climate Risks: Back to Basics
Policy Analysis Series C-030
s cities grapple with the escalating challenges posed by climate change, the concept of urban rewilding has emerged as a promising approach to mitigate climate risks and foster resilience in urban environments.
Urban rewilding entails the deliberate reintroduction or preservation of natural elements within cities, ranging from green spaces and wildlife habitats to native plantings and urban forests. By embracing nature in urban settings, cities can not only enhance their ecological diversity but also address the pressing climate risks they face.
Climate change brings forth a range of risks for urban areas, including extreme heat events, flooding, and reduced air quality. Urbanization itself exacerbates these risks through the creation of heat islands, increased surface runoff, and the loss of natural vegetation.
However, urban rewilding offers a multifaceted solution that can help cities adapt to and mitigate climate risks. By reintegrating nature into the urban fabric, rewilding initiatives provide numerous benefits such as the reduction of urban heat, improved stormwater management, enhanced air quality, and increased biodiversity—all of which contribute to building climate resilience.
Through the lens of urban rewilding, this theme explores the intersection between nature-based solutions and climate risks in cities, delving into the potential of rewilding initiatives to mitigate and adapt to the effects of climate change.
By embracing rewilding principles and practices, cities can forge a more sustainable and resilient path, harnessing the power of nature to tackle the pressing climate challenges that lie ahead.
How can rewilding help reduce climate risks?
Rewilding can help reduce climate risks in several ways:
Urban rewilding can help reduce climate risks by mitigating the effects of climate change, improving urban resilience, and promoting a more sustainable and healthier urban environment.
- Carbon sequestration:
Rewilding can help capture carbon dioxide from the atmosphere and store it in plants, trees, and soil. Trees, for example, absorb carbon dioxide during photosynthesis and store it in their biomass. By increasing the number of trees and other vegetation in urban areas, rewilding can help mitigate the effects of climate change by reducing the amount of carbon dioxide in the atmosphere.
- Cooling effect:
Urban rewilding can help reduce the urban heat island effect, which occurs when urban areas are significantly warmer than surrounding rural areas. This is due to the heat absorbed by roads, buildings, and other infrastructure. Rewilding can provide shade and cooling through the use of vegetation, which can help reduce energy consumption from air conditioning and other cooling systems.
- Reducing stormwater runoff:
Rewilding can help reduce stormwater runoff, which can lead to flooding and erosion. Vegetation can absorb and filter rainwater, reducing the amount of runoff and improving water quality. This can also help prevent the erosion of soil and other pollutants from entering waterways.
- Supporting biodiversity:
Rewilding can help support biodiversity by providing habitats for wildlife in urban areas. This can increase the resilience of urban ecosystems and reduce the risk of species loss due to climate change.
Climate Risks and Cities
There are a number of climate risk aspects relevant to cities. How can rewilded areas help in reducing these risks?
- Extreme Heat:
As temperatures rise due to climate change, cities are at risk of more frequent and intense heat waves that can cause heat-related illness and death, especially among vulnerable populations: Urban areas that are rewilded will reduce the heat absorbed.
Heavy rainfall and sea-level rise can cause flooding in cities, which can damage infrastructure and property, disrupt transportation and commerce, and threaten public health and safety: Rewilded urban areas act as "sponges" that can hold rainwater temporarily until they can flow down drains or river. They can also help recharge ground water reserves, unlike builtup urban areas, where rainwater can only run-off into waterways and cause floods.
Climate change can lead to reduced rainfall and water scarcity, which can affect agricultural production, increase the risk of wildfires, and threaten public water supplies in cities: The green areas that form part of a rewilded area can not only integrate waterbodies in their layout, but due to their permiability, also recharge ground water reserves..
- Storms and hurricanes:
Cities located in coastal areas are at risk of more frequent and intense storms and hurricanes, which can cause flooding, wind damage, power outages, and other disruptions:
Rewiled coastal cities, including coastal ecosystems such as mangrove forests, will form natural buffers against the negative impacts of storms and hurricanes, including stoorm surges and flooding.
As temperatures rise and droughts become more common, cities located in wildfire-prone areas are at risk of more frequent and intense wildfires, which can cause property damage, health problems from smoke, and loss of life:
Urban rewilded areas, particularly those that incorporate water bodies in their layout, can act as an effective barrier to limit the spread of wildfires, particularly to areas inhabited by urban residents.
- Air Pollution:
Climate change can worsen air quality by increasing the frequency and severity of heat waves, which can lead to higher levels of ozone and other pollutants in urban areas:
Urban forests and green areas can significantly reduce the overall impacts of air pollution, and improve the environmental quality of the areas where they are located.
- Water Pollution:
Extreme weather events such as floods and storms can cause runoff from urban areas to enter waterways, leading to increased water pollution and decreased water quality:
Urban rewilded areas not only hold flood waters temporarily like a sponge, but can also filter the water as it passes the soil to recharge ground water reserves.
- Infrastructure Damage:
Extreme weather events can damage urban infrastructure such as roads, bridges, and buildings, leading to costly repairs and disruptions to daily life:
Urban rewilded areas create buffers within urban cities helping reduce the negative impacts of extreme weather events.
- Economic Disruption:
Climate risks can cause economic disruption by affecting transportation, commerce, and other critical sectors in cities:
Urban rewileded areas help in reducing the overall climate risks faced by urban residents, and therefore minimize the potential economic disruption
- Public Health Risks:
Climate risks such as extreme heat, air and water pollution, and disease vectors can threaten public health in cities, especially among vulnerable populations such as the elderly and those with pre-existing health conditions:
Rewilded areas function as urban "lungs" that not only reduce airand water pollution, but also improve the overal well-being of residents by facilitating active lifestyles.