For most of history, cities have been understood in opposition to nature. And this is still how we tend to think of them today, with good reason: the creation and expansion of cities generally involves the destruction of natural habitats – something we are currently seeing on a massive scale as the world urbanises at unprecedented speed.

By Ben Rogers and Geraldine Bedell

Cities have always been great engines of pollution – sinks of bad air and poisoned water – and the environmental harm they do generally extends well beyond their borders. Large numbers of people gathering together with the ambition of improving their living standards (which has been the effect of cities) have razed surr­ounding forests, ruined seas and rivers and exhausted local farmland. Cities and their inhabitants are a major and growing source of greenhouse gases.

It doesn’t have to be this way. Ecological science has found that cities often harbour a surprising variety of wildlife, especially when contrasted to the arid, silent, denatured rural landscapes produced by modern farming techniques. Inhabitants of cities tend to use less energy than country dwellers, not least because urban buildings are generally better insulated and travel is less reliant on cars. And good policies can do much to help cities become sustainable – and even better than sustainable. The interview with Herbert Girardet on page 17 explores the strategies some cities are adopting to develop a genuinely regenerative relation to the natural world.

This issue of the London Essays focuses on London’s natural environment and its contribution to global efforts to combat climate change. London is widely perceived as a green city. And there is much in this. As Clive Anderson reminds us, trees make a vital contribution to the health of cities and London is rich in trees. David Goode reviews London’s considerable biodiversity and notes that for decades, it has led the way in the study of urban ecology. Terry Farrell’s essay points out that far from destroying nature, recent urban development has led to the greening of London – the Docklands are home to a far greater range of flora and fauna today than they were 50 years ago. He and Dan Raven-Ellison argue that London should become the world’s first National Park City.

London has been an early adopter of many enlightened environmental policies and technologies – from 19th-century Clean Air Acts to Ken Livingstone’s Congestion Charge and Boris Johnson’s support for cycling. Jamie Dean explores the latest thinking on the need to understand and promote the city’s green infrastructure, setting out how GLA policy is connecting, meshing and strengthening London’s parks, rivers, marshlands, woods and fringe wild spaces.

So there is great natural richness in London; but the city will need to change if it is to meet the environmental challenges ahead. Herbert Girardet warns that London is in danger of losing its status as a pioneering green city. Daniel Raven-Ellison worries that London’s children are being shut indoors, losing all sense of the city as a place rich in nature. John Vidal points out that, as so often in its history, London is once again doing battle with poisonous air and looks at what will be required to rid the city of air pollution altogether. And Fiona Harvey considers the threat of extreme weather events and how the capital would cope in the event of a major storm.

Fortunately, there is no shortage of ideas to make London a sustainable city. Matthew Pencharz, the Mayor’s environment advisor, sets out what will be needed to ensure that the city’s energy supplies are greener, offering suggestions in particular for the part that local energy production can play. Lucy Siegle’s profile of Agamemnon Otero, an environmental activist with a strong focus on communities, describes how he is already supplying some of London’s poorest housing estates with cheap, renewable solar energy, combating fuel poverty and carbon emissions in one go.

Charlie Leadbeater argues that with a growing population and declining public spending, there is much that we can learn from London’s numerous commons and greens; he calls on the next mayor to create an urban commons fund that would spread the lessons of our commonly-managed green spaces. And David Pitt-Watson and Nick Robins argue that there is a great opportunity for the City, which must maintain its position at the forefront of funding the world’s move to a green, low-carbon economy.

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