Thursday, October 27, 2016

Population Boom Adds to City Threats

A new Atlas of the Human Planet shows how the world’s rising urban population is adding to the impacts caused by climate change.

Flooded slums in the densely-populated city of Jakarta, Indonesia. (Image Credit: Kent Clark via Flickr) Click to Enlarge.
The world’s cities are growing even faster than the human population.  Within the last 40 years, the global population has increased by a factor of 1.8,  but built-up areas have multiplied 2.5 times.

All of this information, and much more, appears in a new European Commission (EC) publication called the Atlas of the Human Planet, prepared to coincide with the recent third UN Habitat conference in Quito, Ecuador.

The Atlas shows that, 40 years ago, most of the world’s 4.1billion population lived in rural areas.  Now more than half live in towns and cities − urban clusters that cover 7.6% of the planet’s land mass, equivalent to an area about half the size of the European Union.

Most of the people in the world are crammed into urban centres with a density greater than 1,500 persons per square kilometre(579 sq mi), and in settlements greater than 50,000 inhabitants.

Altogether, geographers have identified 13,000 urban centres, altogether surrounded by 300,000 “urban clusters” of at least 5,000 inhabitants living at a density of 300 per square kilometre (116 sq mi).
And a group of scientists led by Timon McPhearson, assistant professor of urban ecology at the New School in New York, publish a warning in Nature journal that more urban areas will be built in the next 30 years than ever before just to house and shelter the additional 1.1billion people expected in the next 14 years − most of them in the crowded cities of Asia and Africa.

Whatever problems these new city-dwellers have will be compounded, other researchers warn, by climate change − with ever more frequent and intense heatwaves, droughts, floods, and days of bad air quality.

Around 40% of the world’s people live in coastal cities, and are therefore increasingly vulnerable to floods, tsunamis, surges and tropical storms.

Because of the notorious urban “heat island effect”, cities are inevitably hotter than the surrounding countryside, and many are likely to face a crisis in the supply of safe, clean water.

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