Tuesday, 21 August 2012

On green cities

Urbanisation has been accelerating since 1950, when less than a third of us lived in cities. Now for the first, time more than 50% of the world’s population live in urban environments - and this number is set to grow to over 75% by 2050. 

In 1950, there were 86 cities with a population of over 1 million, by 2005 there were 400 such cities and is anticipated that there will be over 550 by 2015. Projections of populations in megacities are staggering: Mumbai is expected to have 33 million inhabitants, Shanghai 27 million and Karachi 26.5 million by 2025. 

The infrastructure of our cities is expanding fast enough to meet the numbers of people moving from the land to occupy them. Current projections estimate that there will be two billion slum dwellers by 2040, representing a quarter of the global population. Across the world, birth rates in cities are below population replacement rates. Cities may be the only effective form of contraceptive man has invented to date. Cities will be at the core of humanity and its civilization over the coming thirty years as our population peaks. Our environment is breaking. We need to get busy repairing the future. Our cities are key to the new sustainable future we need to build. We need to focus on three things:

 Water – New York City is one of the first to secure its watershed through land purchase and management- making its water supplies sustainable. Sana’a in the Yemen will be the first capital in living memory to be abandoned because of lack of water. Johannesburg faces issues over mine water and drinking water tables that will affect its inhabitants and industries such as SAB miller which relies on that water. Whichever way you look at it - water is the key to the future of our cities. From front loading washing machines to sanitary compaction systems, we have the technology to run our cities sustainably – when will we have the will? 

Land - we cannot continue to use the fertile plains on which most of our cities are built upon for human habitation. We have to build upwards not outwards. We have to stop paving our countryside for car parks and roads and put electric high speed public transport at the core of all we are doing, We also have to plant our cities from the rooftop vegetable projects in the USA, to the visible greening of China’s new cities we must make plants, parks and our people into a sustainable entity. 

Power - Our cities use 75% of all the power we consume. If we were to switch to LED lighting in our major cities, we could eliminate the need for over 30 coal power stations in the US alone. New lateral urban wind farms must be integrated into the design of all our new cities. We must also make power where we use it. Jeremy Clarkson has shown that electric cars are already as fast as any petrol driven equivalent – we have to mandate ‘no combustion vehicles’ in any city by 2025. We must also use the thermal energy beneath our cities to power them. The top 6km of the earth’s crust contains 50,000 times more energy than all the power contained in all the coal and oil that exists on earth. 

Cities are our future, but our future looks bleak unless they become part of the solution to the problems of the environment our planet faces. Whether it is Portland in Oregon, or Malmo in Sweden or the new Chinese Eco City of Shanghai, our cities need to stop being producers of waste and pollution. We need integrate cities sustainably into the plan for fixing our future.

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