The Mexico City subway transports some five million people each day
Death Traps Below the Big Cities
By Stephen Leahy
The ever-growing number of underground transportation networks, shopping centers and parking ramps in the world's mega-cities are vulnerable to natural disasters, warn experts. Not even the wealthiest cities of the United States and Europe have given this serious issue much thought.
BROOKLIN, Canada, (Tierramérica).- Growing land pressures are pushing the world's major cities underground and adding a new dimension to their vulnerability to natural disasters such as floods, earthquakes and tsunamis.
Currently, approximately half of the global population lives in urban areas, and the proportion is expected to reach 65 percent in 2030.
One of the hidden vulnerabilities of mega-cities to natural disasters is the ''underworld'' of subways, shopping malls, parking ramps and public utilities, Srikantha Herath, of the United Nations University, said in a Tierramérica interview from Tokyo.
Nearly all of the world's major cities now have extensive underground areas, including many in the developing world, because ''in densely populated urban areas there is no other space to use," he said.
The matter was one of the many discussed by experts at the World Conference on Disaster Reduction in Kobe, Japan, last week. Ten years ago a major earthquake devastated this southwestern Japanese city, causing 100 billion dollars in damages.
The disaster reduction conference came just three weeks after the Dec. 26 tsunami in the Indian Ocean, a tragedy that has claimed more than 220,000 lives and left millions homeless.
''Cities are by far the most vulnerable, and climate change is increasing those risks,'' said Gordon McBean of the Institute for Catastrophic Loss Reduction at Canada's University of Western Ontario.
Global warming is raising sea levels, making hurricanes, tornados and related storm surges stronger and more frequent. Rainfall is also becoming more intense in some regions, McBean told Tierramérica.
Nevertheless, little thought has gone into reducing the flooding risks of urban underground areas even in North America and Europe, said UN expert Herath.
Tokyo's extensive underground spaces have flooded 17 times in a two-year span, with human lives lost as a result of storms and heavy rains, he said.
Some underground infrastructures have very effective alarm and fire containment systems, but not for flooding, according to Herath.
Often the entry points to the underground areas are the most dangerous during flooding, and problems are compounded by the lack of underground maps that would indicate where water can pass from one space to the next, he said.
Like many mega-cities Tokyo is below sea level. Others are built on flood plains and very vulnerable to storm surges, heavy rainfall and, if located on ocean coastline, tsunamis.
Worst, much of the new urban development in the past 50 years has ignored or forgotten extreme events that happen very rarely such as once in a hundred years, Herath added.
McBean cited the example of the 1999 mudslides near Caracas, Venezuela that killed 30,000 people.
''I remember thinking 'there's a disaster waiting to happen', when I drove by a series of shantytowns clinging to the side of a mountain the week before heavy rains triggered the mudslides,'' he said.
Those shantytowns, as well as the resorts damaged in the slides, were built on top of deposits from mudslides that had occurred many years before.
"The poorest people are always the most vulnerable to natural disasters,'' said McBean.
Some of the countries most vulnerable to natural disaster are Honduras, Guatemala, and the Philippines according to researchers at the Earth Institute at Columbia University in New York City. These are countries that are prone to earthquakes and powerful storms, and also lack the resources to cope with the impact and aftermath of such disasters.
Mexico City, Bogotá, Managua, Santiago, Lima, Quito, San José, and Guatemala City are Latin American urban centers that are high on the risk list of earthquake engineer Omar D. Cardona at the National University of Colombia in Manizales. An expert on vulnerability reduction and risk management, Cardona is the 2004 winner of the United Nations Sasakawa Award for Disaster Reduction.
Reducing risk to natural disasters in large cities requires efforts on many levels including economic, social, and educational, Cardona said in an e-mail from Kobe, Japan.
According to McBean, it is essential to develop warning systems, but that they must be effective in reaching the population, who in turn must be educated in what to do.
The world's greatest construction boom in history is now underway as urban areas grow to include another two billion people within the next 25 years, and ''there's a big opportunity right now to build proper housing for them," Brian Tucker, president of GeoHazards International, a non-profit working on earthquake safety that works mainly in Asia, told Tierramérica.
''The main problem is poorly constructed multi-story concrete housing that become 'death traps' during an earthquake. By contrast, rural dwellings of wood, thatch and mud are much less dangerous,'' he said.
Most countries have building codes and zoning regulations that could reduce the risk but they don't enforce their laws he said. "It's not just a problem of corruption. Local officials don't have the proper training or the positions don't pay well enough to retain professional staff."
Some form of international standards are needed so that transnational corporations don't invest in countries that fail to comply, said Tucker. Governments ''need to be rewarded for doing the right things before disaster strikes.''
* Stephen Leahy is a Tierramérica contributor.