As humans sprawl over the planet and create urban heat islands and habitat degradation, our need for nature – especially for city dwellers – is becoming increasingly palpable.
A comprehensive report by the British Ecological Society has now synthesised evidence on nature-based solutions for cities and outlined tangible ways to tap into the multitude of benefits for the climate, biodiversity, quality of life and resulting economic returns.
“It is clear that there is desire for cities that have better environments and healthier living, but how we do this is the critical issue,” says Marc Cadotte from the University of Toronto-Scarborough, Canada, one of the report’s authors. “This desire for change needs to be translated into action.”
Nature’s services identified in the report include recreation and aesthetic inspiration, sequestering carbon dioxide, absorbing excess rainfall, filtering pollution from air and water, producing healthy soil, nurturing pollinators, and keeping pests under control.
To harness these, Cadotte notes in his built environment chapter that the key to success is understanding the complex interactions between environmental, social and economic factors.
Improving biodiversity in a park will directly benefit the local community, for instance, with access to nature, exercise, fresher air, cooler temperatures and associated health gains.
Green areas could be expanded through initiatives such as ecosystem restoration, green rooftops, sustainable urban drainage systems (SUDS) and community garden allotments – in turn preventing flood risk, increasing food security and harnessing fresh water.
The resulting economic benefits are impressive. The City of London, for instance, valued its eight million trees at about ₤15 (about AU$27) each, equating to a whopping ₤132.7 million (about AU$237.9m) annually. Birmingham, UK, calculated that its ecosystem services are worth a conservative ₤11.6 million (AU$20.8m) each year.
Interdisciplinary collaboration is needed to coordinate initiatives across different sectors such as parks, sewerage and construction. And to be successful, it’s vital to make them inclusive and widely accessible.
“One of the critically important components of implementing nature-based solutions is to ensure equity of access and benefits,” says Cadotte, “because deprived or equity-seeking communities tend to be located in parts of cities that are less green.”
It’s also important to recognise that solutions will vary between cities and urban regions; there’s no single approach that will work for all – but success stories can give inspiration and ideas.
“Singapore has a number of green infrastructure projects like the Gardens by the Bay, or the majestic park-like green roof of the Marina Barrage or even the Khoo Teck Puat Hospital, where one cannot determine where the surrounding park ends and the hospital begins,” says Cadotte.
“Seoul, South Korea, did the unthinkable, restoring an entire river with a city. The Cheonggyecheon stream was completely converted into a cement channel and underground sewer in the 1950s but was restored in the early 2000s into a nature stream that provides immense benefits to residents.”
The Water Sensitive Cities initiative is integrating nature-based solutions into urban areas to improve water quality and management, mitigate floods and relieve droughts, while at the same time improving biodiversity, carbon capture and public health.
Several cities, like Sydney and Toronto, have managed to protect natural areas within their boundaries, now recognised for their environmental benefits and opportunities for residents to enjoy nature.
All that’s needed to build on this and green our cities, says Cadotte, is political will and innovative solutions.
The full report, with contributions by more than 100 experts, will be launched on 12 May.