Bringing nature into cities is hardly a new idea. In fact, it has swung in and out of vogue for more than a century, ever since Victorian social reformer Ebenezer Howard published what became the Garden Cities of To-morrow manifesto in 1898.
Prompted by the squalid, polluted and dangerous environment faced by Victorian city dwellers and their growing alienation from the natural world, Howard’s idea was simple: to create places that brought together the best of urban and rural - homes surrounded by nature, but close to work and shops.
Nature in Singapore
Despite all of the improvements since Victorian times, we still face challenges not that different from those that Howard was seeking to overcome. But now the stakes, in terms of mankind’s survival on the planet, are significantly raised.
On the one hand, a compelling body of evidence suggests that cities remain dangerous places for people to live. The World Health Organization estimates that, worldwide, 7 million people die each year from the effects of air pollution, with nine out of ten of us breathing air that breaches safe limits.
At the same time, and as a direct consequence of man’s activity, nature is being wiped out at a frightening and unprecedented rate. The scientific consensus is that habitat loss, man-made chemicals and climate change are together triggering a mass extinction event as severe as anything since the demise of the dinosaurs.
One recent global study of insects, which are essential for the proper functioning of all ecosystems, found populations to be collapsing at a rate that could see most species wiped out by the end of the century, with 40% already under threat.
In response to both of these challenges, a broad movement has emerged that like Howard, is dedicated to bringing nature back to the places where most people live.
The claims made in favour of greening cities are wide-ranging and backed by scientific evidence. The right kind of greenery can stop urban flooding by storing water, significantly reduce air pollution by filtering out harmful particulates, and cool cities, thereby reducing deaths during heat waves.
If that weren’t enough, green urbanists also claim psychological and social benefits such as reductions in stress and the promotion of community, as well as the economic boost of rising property prices and letting rates.
Much of the rationale stems from the concept of ecosystem services. The idea behind this ecologists’ jargon is an important one: that nature provides a huge range of services to people from provision of food and raw materials, to cleaning air and water, to bringing beauty and joy that have a value, even a calculable monetary one.
“The evidence is that the cost-benefits of all this are really strong” says Tom Butterworth, Technical Director for biodiversity at WSP in the UK, where the government is proposing that all development must deliver a ‘biodiversity net gain’.
And yet investing in green infrastructure is far from being the norm. The problem for developers, says Butterworth, is that not all of these benefits come back to them. “Yes, good infrastructure might raise prices a bit, but it’s unlikely to cover the cost of putting in the infrastructure, while the health and wellbeing benefits will play out for the residents over the long term.”
This tension is amplified in high-value urban environments, where there is huge pressure to make a site as economically productive as possible. In prime central London, for example, residential space can sell for up to £3,000 per square foot, which makes it extremely difficult to make green infrastructure pay.
In a compact city, there is just less land available for nature such as woodlands and other forms of unmanaged greenery. The scarcity of land is a big challenge for landscape planners.
Meanwhile, Clare Warburton, Principal Green Infrastructure Adviser at UK government agency Natural England, is exploring ways to measure the invisible benefits of green infrastructure.
Strong evidence suggests that, if greenhouse gas emissions are to be reduced, cities need to be compact enough to be walkable and support public transport.
The pressure to make every inch pay means prioritising green infrastructure that can deliver multiple benefits from a single intervention, using the economic benefit as a Trojan horse for doing lots of other great things. For example, a piece of flood water management infrastructure can also be a park, as well as improving air quality.
With both biodiversity and a desire to minimize maintenance costs in mind, landscaping in cities is taking a new form which is less manicured and much less dependent upon planting imported species unsuited to local conditions.
The idea is that this fosters ecosystems that can sustain themselves to develop naturally, rather than environments that require constant intervention.
This new form does not suit everyone’s idea of what nature in cities should be. If you don’t work with native species, then you can’t reduce heat in a sustainable manner and you need a tonne of water. If you work with what’s locally available, the maintenance cost is not as high, and you’re celebrating your own culture.
But it’s very hard with biodiversity because it’s not so tangible. We have to change the mindset that the environment is a cost. Our current economic system makes it look like it makes sense to do certain things, simply because the environment is not factored in.
We’ve got to change the system to recognise that development requires a healthy environment.
(From an article by Joey Gardiner)