Landscape, sustainability and the city

Today, for the first time in human history, more than half the world's population lives in towns and cities rather than in the countryside. Hence, what happens in cities is profoundly important for sustainability, both for the welfare of the people who live there and for the demands that humankind makes on the earth's resources. The modern city draws those resources from across the world and requires a huge notional land area to assimilate its waste products; it has a very large ecological footprint. However, because this is where people and material transformations are concentrated, innovation in cities to improve the effectiveness of resource use can make an important contribution towards sustainable development. One approach is through shaping the city and there has been much debate about the extent to which urban form and function can contribute to sustainability. The debate gains contemporary relevance in the UK as societal change pushes up the rate of household formation, especially in South East England. The policy consensus favours urban containment and polycentric development with an implied increase in housing densities. However, even the most committed urbanists recognise the importance of providing a richly vegetated and biodiverse urban environment to sustain quality of life. Despite this, in Britain, there has been a significant decline in the quality of public open space. One way to redeem the potential of these important assets is to recognise properly the contribution that they can make to economic, social and environmental welfare - the three pillars of sustainability. The proper context for this is to develop a landscape planning and management strategy based around multi-functional green networks of corridors and spaces - what is coming to be known as 'green infrastructure'. This chapter discusses new research which emphasises that the green infrastructure may have an even greater importance in a changing climate. Natural processes do not stop at the city limits, rather they are intensified by urbanisation and these effects, such as the urban heat island and accelerated runoff, are multiplied by climate change. A comprehensive approach to planning and designing the green infrastructure of all areas, including town centres and residential areas, may be the most effective way to realise some of the benefits, whilst moderating the impacts of climate change.