“The way cities have grown since World War II is neither socially or environmentally sustainable and the environmental cost of ongoing urban sprawl is too great to continue,” says Dr Karen Seto, associate professor of the urban environment at Yale University.
News Source: ABC
Expanding cities threaten to eat up a swath of land twice the size of New South Wales in less than 20 years, an international conference has heard.
Cities are growing to accommodate a rising global population and as countries like China, India and Brazil pursue fast economic growth.
The world’s cities are currently on track to occupy an extra 1.5 million square kilometres by 2030 – equivalent to one-fifth the area of Australia – spelling growing greenhouse gas emissions and resource demand, say experts at the Planet Under Pressure conference in London.
“The North American suburb has gone global, and car-dependent urban developments are more and more the norm.”
Professor Will Steffen, a global change expert from the Australian National University says the most rapid transformations have occurred in the last 50 years.
“Many human activities reached take-off points sometime in the 20th Century and sharply accelerated towards the end of the century. It is the scale and speed of the Great Acceleration that is truly remarkable. This has largely happened within one human lifetime.”
The United Nations sees global population rising to 9 billion people by 2050 from 7 billion now, adding around a million people each week.
Most of the growth is expected to come in urban centres with migration from rural areas potentially adding another 1 billion people to cities. That would increase the total urban population to 6.3 billion people by 2050 from around 3.5 billion today.
Steffan warns society may reach a threshold this century.
“Either we turn around a lot of these trends – the carbon dioxide trend, deforestation and so on – or we allow them to continue and push the Earth as a whole across a threshold whereby a lot of these tipping elements are activated and the world moves into a new, much warmer state,” he says.