The Year the Earth Changed

‘The Year Earth Changed’, narrated by David Attenborough, reflects on the dramatic changes the world experienced during lockdown and is brimming with inspiring images of wildlife adapting and thriving in unexpected areas without humans. Some of the documentary’s most striking imagery shows a stark contrast between wildlife and the urban areas they begin to invade, like a hippo wandering into a gas station in Saint Lucia or a puma prowling the streets of Chile.

The documentary highlights the ways in which we have excluded and negatively affected nature in our everyday lives, imploring us to find better ways to coexist with the natural world.

Environmental benefits

Rewilding cities can help mitigate the effects of climate change by making our cities more resilient. Many of the threats cities face from climate change, such as an increasing frequency of extreme weather events, an increasing threat of tropical diseases, and rising sea levels, could be reduced through urban rewilding in the following ways.

• Restoration of natural areas and processes, such as the capture and storage of rainwater by trees.
• Reduction of city pollution and sequestration of carbon in the atmosphere.
• Boosting biodiversity by introducing more green areas and recovering diverse natural spaces. This could provide food and habitats for wildlife and form green corridors to link together fragments of nature.
• Urban rewilding could also reconnect those living in cities with nature, enabling people to develop stronger connections, recognise its importance and foster a sense of stewardship of the natural world.

Economic benefits

Connecting our cities to natural processes could mitigate problems associated with urban areas. For example, a common problem in cities is the ‘urban heat island’ effect, a phenomenon that occurs in dense urban areas when heat generated by human activity (e.g. by people, transport, industry) is trapped by concrete structures. As a result, urban areas are a few ºC hotter than the neighbouring countryside. The associated problems with this include:

• Increased demand and expenditure on cooling, resulting in higher energy consumption and burning of fossil fuels.
• More pollutants emitted and therefore poorer air quality, amplifying heat-related illnesses and mortality.
• Warmer water within a city is released into streams, rivers, and lakes, creating problems for aquatic ecosystems.

Rewilding urban areas can play a major role in addressing these problems whilst creating benefits in other areas.

• By introducing more greenery, particularly on roofs, plants could reduce the 'urban heat island' effect by providing shade and cooling the air through evapotranspiration.
• This also removes air pollution, sequesters carbon, and regulates water in the city by trapping storm water and filtering out pollutants that the rain carries. 
• Rewilding could make a place more attractive, generate nature-based tourism and save money by making the city more resilient to events like flooding.
• Rewilding cities could also reduce the need and cost for active management of our green spaces. This includes procedures such as mowing lawns, using pesticides, watering, and weeding, since rewilded areas can have higher biodiversity and also be self-regulated.

Misconception and fears

People are often skeptical of rewilding because it is sometimes associated with the reintroduction of large animals and of a return to a pre-human environment. However, urban rewilding focuses on finding a compromise between the needs of humans and nature, and hopes to include cities as part of a wider solution to nature’s current decline. This rewilding is more on the scale of planting wildflowers, designing better, sustainable urban spaces and changing our ideas of what cities must look like. 

That being said, while urban rewilding won’t see the reintroduction of apex predators, smaller animals like water voles might be introduced to help ecosystem restoration and our cities might see more animals like birds, bees, and butterflies. City rewilding and how it hopes to play a role in restoring ecosystems and natural processes might also reduce animal/human conflicts since we would be reducing the human disturbance on animal habitats that forces them to adapt and enter our urban areas.

Others following suit

In Dublin, the city council reduced mowing and use of pesticides and so 80% of its green spaces are now pollinator friendly.

Abandoned spaces have become successfully rewilded in: Germany, where abandoned lots in Frankfurt, Dessau and Hanover were transformed into wildflower meadows.

New York, where a former railway track has been transformed into a public park; and Nottingham, which restored a central shopping centre into a wetland.

In the city of Harbin, an urban storm water park has been created to filter and store storm water as well as provide habitats and recreational use for residents.

Other cities are beginning to utilise nature-based buildings. For example, Liuzhou Forest City in China began construction in 2020 and will be the world’s first forest city. An estimated 40,000 trees and 1 million plants from over 100 species will cover the facade of all buildings and infrastructure, absorbing around 10,000 tons of carbon dioxide and 57 tons of pollutants per year, while producing about 900 tons of oxygen. The city will be energy self-sufficient (using geothermal and solar power) and will be integrated into the surrounding environment.