Counting the Cost
As cities continue to expand outward, the debate on the environmental threat of urban sprawl has become more urgent and more vociferous. UK planners and architects are divided on the best way forward; whether to continue to build new housing developments or regenerate existing city spaces for high density living, protecting greenfield land from the excavators. Central to any policy are considerations about air quality, traffic congestion, public transport and refuse disposal.
Architect Will Alsop, for instance, suggests reshaping the current pattern of development along the tarmac arteries that already join cities, to create a new city identity. Along the M62 from Liverpool in the west to Hull in the east, Alsop envisages a 130-mile long, 20-mile wide band of urban and industrial development creating a linear 'super city'. But he acknowledges that with 15.4 million residents on the move, a radical change would be needed to get people out of their cars on to more communal forms of transport
And if Alsop rolls out his giant urban carpet, it would also slice through the natural wildlife habitat, akin to Hadrian's Wall, separating species in the north from species in the south.
Growing challenge
From the start of civilisation, humans have had to consider the environmental challenges that arise from living together in groups. They had to consider the proximity of their eating and sleeping areas to their latrines, dispose of food scraps that would attract disease-carrying scavengers, and take care not to poison their watercourses. The greater the size of the living group, the greater the size of the environmental challenge faced.
Since the early 1900s, when the majority of people lived in rural communities, the proportion living in cities has risen rapidly, reaching 30% by 1960 and 47% by 1999. By 2030 it is predicted the figure will be 61%.
Simultaneously, the world's population has increased dramatically – from 1 billion in 1800 to 6.3 billion today. The population of Ancient Rome approached half a million, but now there are 23 cities worldwide with populations exceeding 10 million, many in developing countries, which now face the same problems that Western cities confronted decades ago.
Pollution problems
A fundamental challenge for any city is dealing with the waste products of its people. For centuries, Londoners lived without an efficient sewerage system, but it was not until the late 1850s when a devastating cholera epidemic was recognised as the result of water borne bacillus that the city's chief engineer Joseph Bazalgette instigated the construction of hundreds of miles of sewer tunnels beneath London's streets.
Air pollution became another threat to health as the industrial age advanced. In London, the infamous 'pea soupers' were a result of a noxious mix of smoke and sulphur fumes from the tonnes of coal powering homes and factories. In 1952, conditions brought on by trapped smoke and light winds caused an estimated 4,000 premature deaths from bronchitis and pneumonia, and action was finally taken. In 1956 the Clean Air Act was passed, outlawing the burning of coal in the city limits.
Replacing smoke as a major pollutant in the UK are exhaust fumes from an ever growing number of vehicles. Carbon monoxide and nitrogen dioxide may be less visible but are equally toxic, and may account for 1,200 extra deaths each year, according to the Met Office.
European cities like Amsterdam, Copenhagen and Brussels have taken measures to hand their cities back to pedestrians. Britain too has introduced cycle lanes, park and ride schemes and bus lanes. But is it enough to stem the tide? London's congestion charges on motorists for taking their vehicles into the central zone is just the latest in a long line of traffic control measures in the capital, stretching back to disposing of the horse manure from horse-drawn carriages that threatened to bury London in the stuff 100 years ago.
Better together
But the finger of blame cannot be pointed exclusively at cities. In fact, city living can have positive environmental benefits.
One example is the cost of 'food miles'. Delivering food to 100 cities by land, sea and air is more efficient and emission-saving than delivering it to the same number of people spread out over 10,000 villages.
Collecting waste is also more energy efficient in cities. The huge disposal task is certainly easier if people live in city groupings.
And what about nature? In the US, only 5% of the country is consumed by the built environment (towns, cities, roads), with most of the population centred in cities. Although much of the remaining land use is agricultural, it does leave room for wildlife.
Humans seek contact with nature, for several reasons, including recreation, aesthetic appreciation, or sheer emotional or spiritual replenishment. But with urban sprawl, the countryside becomes more remote. What is a short walk for town dwellers becomes a car journey or train ride for city dwellers, increasing the distance from nature both metaphorically and literally. This alienation is not good for wildlife either. A human population that has no contact with nature and its wildlife is less likely to value it.
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