Michael Richardson: Bigger the city, the bigger the disaster

For the first time in human history, more people will soon live in cities than do not. Urbanisation is intensifying as greater numbers of people, especially in Asia, leave the countryside in search of jobs, better living standards and wider opportunities.

Fifty years ago, 30 per cent of the world's population lived in urban centres; by 2030, that proportion will approach 60 per cent.

The 21st century will be the first truly urban century. In the year 2000, there were more than 410 cities with more than one million inhabitants. Not only are there more cities, they are becoming much bigger.

After the Boxing Day tsunami disaster, experts are warning that the rapid growth of mega-cities is exposing a greater proportion of the world's population to catastrophic risk from earthquakes, storms, floods and epidemics.

"Mega-cities are becoming the most vulnerable of all," says Salvano Briceno, head of the United Nations' disaster reduction body.

The UN says 11 of the 20 biggest urban centres are in East and South Asia. They include Tokyo and Osaka-Kobe in Japan, Mumbai, New Delhi and Kolkata in India, Jakarta in Indonesia, Shanghai and Beijing in China, Dhaka in Bangladesh, Karachi in Pakistan and Manila in the Philippines.

Mega-cities are defined as those with a population of 10 million or more and a dense concentration of people. In developing and newly industrialising countries, many of them live in slums.

Urban zones worldwide are gaining an estimated 67 million people a year, or about 1.3 million every week. By 2030, about five billion people are expected to live in cities - 60 per cent of the projected global population of 8.3 billion.

But lax building regulations, poor living conditions and weak rescue services make urban dwellers vulnerable to natural disasters.

The World Health Organisation warned last October that many cities are growing so fast that economies, services and infrastructure cannot cope.

This will result in outbreaks of infectious disease and an upsurge in crime, violence, environmental degradation, pollution, poverty and unhealthy lifestyles.

In Asia - which has half the world's city dwellers - more than 1.5 million people already die every year from diseases related to air pollution.

But climate change and the undersea earthquake off Indonesia that triggered the tsunami have put huge urban centres, many of them in tremor-prone coastal areas, in a new high-risk category.

More than 250,000 are reported to have been killed in the tsunami disaster. Hundreds of thousands more were injured or lost their homes and livelihoods. Families were shattered, leaving thousands of orphans.

Michel Jarraud, secretary-general of the World Meteorological Organisation, says climate change is contributing to the number of weather-related disasters, which account for 90 per cent of natural catastrophes.

Jan Egeland, the UN chief co-ordinator of humanitarian affairs, describes giant cities as places that expose concentrated populations to the worst collective risks in human history.

"We have millions of people now who are living in death traps in huge, densely populated slum areas on fault lines or in flood-prone areas.

"If things go badly wrong, you could have the worst catastrophes in human history."

The UN and other experts have proposed that all buildings chosen as safe havens, including hospitals and schools, be constructed to withstand severe natural disasters.

Dr Shigeru Omi, the WHO's regional director for the Western Pacific, says shifting authority from central governments to municipalities can help make policies, plans and actions more responsive, especially to the needs of the urban poor.

By 2015, the world's top 15 cities will have a combined population of 302 million, according to figures from Munich Re, the German reinsurer, which has produced a report on what it called mega-risks associated with huge cities.

That is 50 million more than in 2000, and 220 million more than in 1950, when only New York had a population of more than 10 million.

Of the 15 cities with populations above 14 million in 2015, only three - Tokyo, New York and Los Angeles - are in countries classified as high income. Of the remainder, eight are in Asia.

In terms of insured risk, Tokyo is by far the world's most disaster-prone city because of its huge concentration of wealth and population in a highly active earthquake zone.

Munich Re gives it a risk index of 710 against 167 for its nearest rival, San Francisco.

Japan is vulnerable to cyclones but the big danger is earthquakes. Tokyo was flattened by tremors in 1923 and subsequent fires. Experts say a major quake is long overdue.

An earthquake in Kobe in 1995 killed more than 6400 people and caused economic losses of nearly US$100 billion.

Egeland says one of the most frightening prospects is a mega-disaster in a mega-city.

"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."

* The writer, a former Asia editor of the International Herald Tribune, is a visiting senior research fellow at the Institute of Southeast Asian Studies in Singapore.