Earthquakes, floods and other natural disasters could kill millions in the world's teeming "mega-cities" and time is running out to prevent such a catastrophe, a UN expert on emergency relief has warned.
In Kobe, a city which is still nursing wounds from the earthquake that struck a decade ago, the UN director of emergency relief, Jan Egeland, painted an apocalyptic picture of imminent natural disasters in the world's mega-cities, predicting they could be "one hundred times worse" than the Boxing Day tsunami.
"Perhaps the most frightening prospect would be to have a truly mega-disaster in a mega-city," Mr Egeland told the World Disaster Prevention Conference. "Then we could have not only a tsunami-style casualty rate as we have seen late last year but we could see 100 times that in a worst case," said Mr Egeland, who warned that "time is running out" to prevent such a catastrophe.
Mega-cities have a population of 10 million or more and a dense concentration of people, many of them in slums.
"Time is running short for some of those mega-cities in Asia, in Africa and in Latin America," Mr Egeland said.
With a population of more than 35 million people, the greater Tokyo area tops the list of the world's mega-cities, followed by Mexico City with 19 million, greater New York at 18.5 million, Bombay at 18.3 million and Sao Paulo at 18.3 million. Delhi is expected to join by 2015.
"Some of the mega-cities are earthquake prone, others are prone to flooding. We have to have city planning, we have to have development, we have to have investment in the poor areas, because the poor people now are the most vulnerable," Mr Egeland said.
"There is still time to prevent that, and we hope that some attention could be given to the mega-cities and not just to the countryside, which we normally associate with tsunamis and with flooding and with drought."
As the world's population continues to grow, so will the size of mega-cities across the globe, stretching resources and the ability to cope with disasters.
The chaotic growth of slum-ridden urban centres in Asia, Africa and Latin America weighs heavily on the minds of disaster planners such as Mr Egeland, but it is Tokyo that causes most nightmares in boardrooms and governments across the world. Squatting on one of the world's most unstable geographical foundations, Tokyo is shaken by dozens of earthquakes a year and lives in fear of a repeat of the massive 1923 earthquake and tsunami that levelled the city and took 140,000 lives. Plans to move the capital have been shuffled back and forth between bureaucrats for years but the city has continued to expand.
Today, the equivalent of roughly half of the population of Britain lives in this small corner of the planet and the population of Dublin files through a single city station - Shinjuku - every day. A government study last year predicted that a 6.9 earthquake directly under the city could kill 13,000 people, destroy 800,000 homes, and leave 6.5 million stranded, putting the chances of it hitting Tokyo before 2034 at about 70 per cent. But there are far worse scenarios. A magnitude 8 earthquake similar to one that struck in 1923 could kill 150,000 and destroy 2.6 million buildings. Last week, a report by a German insurance firm put Tokyo top of a list of the worst cities to be in during a disaster.
Death and destruction from a huge quake in Tokyo would probably be followed by enormous financial repercussions for the world. Today, the city boasts an economy larger than Australia's and is headquarters to some of the planet's largest banks and corporations, which have hoovered up billions of dollars in assets across the world. Experts say the quake will trigger mass selling of these assets and possibly a world financial crash.
In a book about the coming Tokyo quake subtitled Sixty Seconds That Will Change the World, a journalist, Peter Hadfield, wrote: "It sounds like fiction but that's the problem. Though this nightmare scenario has already been accepted and laid out in several ... government studies as the consequence of another 1923-type earthquake, it is so horrendous and catastrophic, people simply refuse to accept it."
Every year on 1 September, thousands of people in Tokyo practice disaster drills and the government is working on a manual containing evacuation guidelines. But some people are not convinced it is safe. Yoshio Kushida, a scientist who grew up in Tokyo said: "It's the most dangerous city in the world. There is just no way I would live there."
CITIES AT RISK
Population: 35.3 million
Population in 2015: 36.2 million
Risks: Earthquake, tropical storm, tornado, storm surge
Population: 19 million
Population in 2015: 20.6 million
Risks: Earthquake, volcano, tornado
Population: 18.3 million
Population in 2015: 22.6 million
Risks: Earthquake, flood, tropical storm
Population: 18.3 million
Population in 2015: 20 million
Risks: Flood, tornado
Population: 14.1 million
Population in 2015: 21 million
Risks: Earthquake, flood, tornado
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