On October 31, the world population will officially reach seven billion
according to the UN. Reaching that historic landmark reminds us of the massive
challenges, including here in the Middle East, created by an ever-increasing
number of humans on the planet.
Growing populations are also driving
another mega-trend – urbanization through migration. In 1800, less than three
percent of the world’s population lived in cities, yet by the end of 2008, this
had risen to more than 50%, and there were 26 megacities (cities of 10 million
or more inhabitants), including Istanbul, Cairo and Kinshasa.
economic success of megacities, governments at every level are preparing for the
growing risks that these massive urban centers pose. For instance, will it be
possible to continually meet the everyday needs of food, water and health, and
also deal with the growing vulnerability of megacities to environmental stresses
exacerbated by the effects of climate change? There is already cause for some
alarm. For instance, the tsunami in Japan this year forced Tokyo to reconsider
its approach to nuclear power and to protecting its cities.
the 2003 heat wave in Paris was so devastating because both the public and
authorities were unprepared for dealing with such extreme weather conditions,
which were exacerbated by building practices, especially the lack of
During the 21st century, megacities across the world
will continue to grow, as will other large urban conglomerations. Energy demands
will increase, as will demand for food, water and other resources.
associated increased carbon emissions are contributing to global warming and
pose their own climate risks. In China, where people are being subsidized to
move from the countryside, cities have grown by a factor of two in only five
years. The local urban “heat island” effect means temperatures in cities are
increasing about three times faster than elsewhere.
THE MAIN risk for
megacities on coastal plains is their increasing vulnerability to rising sea
levels and river flooding, such as those devastating Bangkok right now. There
will be further episodes such as the one in New Orleans six years ago when it
was hit by Hurricane Katrina, without adequate protection and flood warning
In at-risk countries, such as the Netherlands, researchers are
preparing for these type of problems.
For instance, Delft University’s
Hydraulic Engineering Department has been developing a state-of-the-art early
warning and monitoring system, including the effects of subsidence, to protect
The larger the urban area, the greater the damage
that natural hazards can inflict, and increasingly it may be impossible to
protect life and property even if there is a perfect warning system. As a recent
hurricane in Houston showed, despite the known dangers from combined hazards
such as winds and floods, there is now insufficient time to evacuate some cities
safely, even highly developed ones.
So there is a pressing need for
cities to develop emergency refuge areas. In some cases these may already exist.
For instance, Canvey Island in England still keeps its mound in case of another
severe flood like that of 1953.
In most cases, however, refuges will need
to be built from scratch.
Thus, engineers and planners are considering
how to identify and design such emergency centers, whether outside or within
buildings, and how these should be connected to the wider urban system,
Training populations to use the centers
effectively is also essential.
Refuges have successfully withstood
cyclones and floods in Bangladesh and, unlike those in some other developing
countries, have been used by vulnerable communities, because they could take
their vital farm animals with them – without the animals they are
Emergency energy supplies for communities, which are essential
for medical emergencies, should improve in future. This is especially so using
advanced solar power – effective even in cloudy conditions.
the failures to deal with some of the recent hazards impacting on megacities,
governments at every level are planning for multiple hazards and are developing
strategies for managing the range of environmental factors which could emerge.
Moreover, other research teams are collaborating in construction of “system
dynamics” models for the operation of infrastructure, environment and
socio-economic aspects of megacities.
These models resemble well-known
computer programs for global climate change and its interconnections to economic
As with Delft’s coastal monitoring system, these will help
cities to predict which hazards they face and help them decide how to
The London mayor’s office is taking a particular interest in
which policy options emerge as London continues to expand. Meanwhile, numerous
other cities are experimenting with air quality hazard indicators based on
complex system models to appraise citizens about how the environment in their
cities varies hourly and over the longer term.
What these models need is
improved availability of relevant environmental and socio-economic data. Here,
international agencies such as the World Health Organization and the World
Meteorological Organization, as well as national governments, need to
collaborate with a wider range of organizations, and make maximum use of new
media. This will better enable data showing how people experience both rapidly
occurring hazards such as tornadoes, and slower, but still deadly, phenomenon
such as loss of crops from rising sea levels and salt
Fortunately, megacities have a global organization for
information exchange and collaboration called C40 Cities. The future agenda here
includes enhanced inter-city cooperation on policies for dealing with hazards,
and putting more pressure on national governments to assist, especially with
finance and data, and strategic priorities.The writers are,
respectively, a visiting professor at Delft University and vice chairman of the
Global Legislators Organization for a Balanced Environment (Globe), and
professor of mechanical engineering at the University of Hong Kong.