Global Report on Human Settlements 2007 - PoA-ISS

Policy responses to disaster risk
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and livelihoods. This gap has been filled in some neighbourhoods
by community-based hazard and risk mapping
projects. This data, combined with national- and city-level
records of past events, can be used to identify priorities for
urban planning and construction standards.
Less information is available at the global scale for
hazards that affect the lifelines to a city such as drought, or
emerging hazards such as heat and cold shocks. <strong>Global</strong>-scale
data can be used to extend analyses of hazard exposure
beyond the municipal boundary to demonstrate the vulnerability
of cities to disasters affecting their hinterland by
disrupting trade, or blocking access and flows of resources
and waste.
■ Mapping human-made hazard
National directories of human-made hazards are becoming
more common, and many are open to the public. In the UK,
the Environment Agency hosts a pollution and hazardous
waste sites inventory. This is searchable by postal code and
also provides information on water quality and flood hazard. 8
In the US, Green Media’s Toolshed website includes a
searchable scorecard, which provides data on chemicals
being released from any of 20,000 industrial facilities, or a
summary report for any area in the country. 9 More difficult
is the mapping of human-made risk associated with industrial
facilities, buildings’ integrity or transport infrastructure.
Much of the information needed to build comparative
hazard datasets is commercially valuable and therefore not
released to the public.
Local authority land-use planning maps and schedules
include information on industrial sites where hazardous
activities are undertaken, and can be used as a basis for
urban industrial hazard mapping. This is particularly valuable
for assessing the risk of human-made disasters caused by
natural hazards. More difficult is the acquisition of data on
informal-sector industrial activities, such as tanneries or
fireworks factories. These might not represent a significant
hazard individually; but, in aggregate, unplanned industrial
activity is a major risk to health from air, water and ground
pollution and from fire and explosion hazards. Risk is heightened
because of the unregulated nature of informal
industrial activity and its close proximity to densely settled
residential areas.
Risk assessments for individual cities
As noted in Chapter 7, there is limited comparative data on
natural disaster risk and impacts at the city level. Two initiatives
have made major contributions at this level of analysis –
namely, the Natural Hazards Risk Index for Megacities by
Munich Re (see Chapter 7) 10 and the Earthquake Disaster
Risk Index used by GeoHazards International (GHI).
GHI developed and applied an Earthquake Lethality
Estimation Method in 2000/2001. The method produces
results that indicate the relative severity of earthquake risk,
the sources of risk within each city, and the relative effectiveness
of potential mitigation options. The same results are
also produced for the exposure of school children to collapse
of educational buildings. The method was applied to cities in
Box 8.2 Estimating urban loss of life to earthquakes
GeoHazards International’s (GHI) Earthquake Lethality Estimation Method estimates the
number of lives that would be lost if all parts of a city experience earthquake shaking at a level
that has a 10 per cent chance of being equalled or exceeded in 50 years. The method has been
applied to assess the risk of life loss in 22 cities in the Americas and Asia. Deaths caused by
building collapse, earthquake-induced landslides and fires are included. Capacity for organized
search, rescue and emergency medical care is also considered. Results are validated over time
through a comparison of estimates with actual loss. GHI’s approach is especially noteworthy
because of its emphasis on the safety of school children, which reflects the vulnerability of
schools.
Data is collected through meetings with local experts and city officials dealing with
seismology, soils and landslides; city planning; building inventory; school buildings; emergency
response; medical emergency preparedness; hospital emergency preparedness; and fire
preparedness.
Results show great variation in the risk of earthquake-induced loss of life in cities. For
example, in the American region, a person living in Mexicali is almost three times more likely to
be killed by an earthquake than a person living in Quito, and about ten times more likely than a
person living in Santiago. In the Asian region, a person living in Kathmandu is about nine times
more likely to be killed by an earthquake than a person living in Islamabad and about 60 times
more likely than a person living in Tokyo.
GHI’s approach is also able to identify differences in the immediate causes of death and,
thus, guide the subsequent development of mitigation strategies and policies. For example, in a
comparison between Delhi and San Salvador, while most of the deaths in Delhi will be due to
building collapse and earthquake-induced fires, an important fraction of the deaths in San
Salvador will be due to earthquake-induced landslides.
The analysis of school risk also shows differentiated vulnerability across cities. A school
child in Kathmandu is 400 times more likely to be killed by an earthquake than a school child in
Kobe and 30 times more likely than a school child in Tashkent.
Source: GHI, 2001
the Americas and Asia, differentiated by city size (see Box
8.2).
The philosophy of GHI is that loss estimation is both a
process and a product. The process aspect engages decisionmakers
at the community and city levels and recognizes that
data alone is insufficient to effect change in human behaviour.
The process of assessment includes local expertise and
favours rapid assessment that can feed into ongoing
decision-making over possibly more accurate, but also more
costly and less participatory, methods. Readily available information
is supported with data from local experts. The final
results allow a quantitative assessment of the effectiveness
of mitigation options under consideration.
Including indicators for social vulnerability in risk
assessment at the city level is difficult since it requires the
availability of relevant data on population and social indicators.
For instance, research on risk of heat waves in London
has used census data and is appropriate for those countries
that have spatially disaggregated and high-quality census
data. 11 In the majority of cities, especially those that are
rapidly expanding in poorer countries, this is not a reliable
source of data. Other methods, such as the use of satellite
information on night-time lights and fires, offer an alternative,
but still not comprehensive, measurement of
population density in rapidly expanding and poor cities.
Comparison of disaster risk between districts within a
city has rarely been undertaken. One example of this
…there is limited
comparative data on
natural disaster risk
and impacts at the
city level