New Delhi: What happens in cities will to a large degree decide whether humanity can lower its common environmental footprint, or whether it will face a greater risk of substantial climate change and other daunting ecological problems.
The United Nations Population Division estimates that over half of the world's population lives in urban centres today, a number likely to grow to almost 60 per cent by 2025 and to 70 per cent by 2050.
Today's cities are already responsible for about 80 per cent of greenhouse gas emissions, according to UN-Habitat, making them in carbon terms a highly inefficient way to live. This need not be. Cities have built-in economies of scale, which should allow much lower average environmental footprints for residents. Achieving these savings, however, means taking challenges like global warming, water use or waste seriously -- in particular creating and modifying infrastructure elements as well as incentives to make greener lifestyles viable.
A Siemens study of London looked at some of the options available in creating more sustainable urban infrastructures. Sustainability is a wide-ranging concept. This research focused specifically on technological levers that could help make an environmental impact - reduce greenhouse gas emissions, water usage and waste disposal in landfill - and that would have an effect before 2025 without any compromise in lifestyle.
It did not deal with social or economic aspects of sustainability. Nor did it consider behavioural change, except to the extent that the decision to purchase a new technology is in itself a behavioural step. Broader behavioural change was, of course, important, but its effect has not been specifically calculated for this report.
This research centres on London as a case study. It takes into account that differences exist between all cities. London, for example, has a smaller environmental footprint than New York in certain areas, such as air pollution, buildings and water use, while other cities, such as Tokyo, Rome and Stockholm, show that London has room for improvement.
Whatever its relative performance, many of the city's environmental challenges share much in common with those facing comparable large urban centres.
London is also a particularly helpful case because of its efforts to take a lead on many of these issues.