Geoscience Reference
In-Depth Information
ship between the physical probability of an event and its consequences, whether
economic, social or both, is captured by formulations of risk as a multiplicative
function of both:
Risk
=
f
(probablility
×
consequences)
Combining probability and consequences into a single mathematical function allows
policymakers to use cost-benefi t analysis and other decision support tools designed
to optimise the aggregate level of expected annual fi nancial loss. Cost-benefi t analy-
sis is now a standard feature of project appraisal for fl ood defense and other hazard
mitigation schemes. Apart from the technical diffi culties of actually quantifying and
monetising levels of exposure to hazards whose probability and consequences are
often highly uncertain, there is a fundamental ethical issue posed by this fi nancial-
based method for assessing hazard exposure. Measured in dollar terms the conse-
quences of a given event will always be higher if it affects richer people. Financially
based tools, like cost-benefi t analysis, are blind to the distributional effects and to
the consequences for the least worst off, which are central to Rawlsian conceptions
of justice (Johnson et al., 2007).
One of the attractions of the concept of vulnerability is that it highlights ques-
tions about the uneven effects of a given hazard on differentiated societies. Different
vulnerability profi les will determine socially differentiated impacts experienced by
people otherwise similarly exposed to the same level of hazard intensity and fre-
quency. In fact, many researchers argue that environmental hazards may be defi ned
as situations where environmental extremes come into contact with vulnerable
human populations (Mustafa, 1998). Vulnerability is defi ned as the susceptibility
of an individual or group to suffer damage from environmental extremes and the
relative inability to recover from that damage (Cutter et al., 1996, Adger, 2006).
Levels of vulnerability depend upon long-term social, economic, political and physi-
cal factors. Poverty, age, gender, socio-economic status, ethnicity, state of the
infrastructure, quality of governance or a combination of any of these factors are
key determinants of whether certain populations will be vulnerable to hazards. The
women and children living in the coast of Bangladesh without means of evacuation,
for example, are much more vulnerable to coastal storms than affl uent Florida resi-
dents able to get themselves out of harm's way. In addition to these huge differences
in hazard vulnerability between developed and developing countries, there are also
major differences within societies, as evidenced by the experience of Hurricane
Katrina (Colten, 2006). Offi cial statistics from the St. Gabriel Parish morgue in New
Orleans show that the majority of the nearly 1,000 fatalities recorded there were
poor, elderly and African American. Such vulnerable social groups were less able
to evacuate the city as Hurricane Katrina approached (Louisiana Department of
Health and Hospitals, 2006).
Hazards response may entail multiple steps including pre-disaster planning and
preparation, vulnerability mitigation, disaster relief, long-term reconstruction and
fi nally development directed towards building resistance and resilience in the face
of existing and future hazards. Which particular step or confi guration of steps is
emphasised in hazards policy will bear upon the magnitude of damage suffered
during specifi c disasters. Relatively recently, in the aftermath of the 2004 Asian
Tsunami and the 2005 South Asian earthquake, national governments, international
donors, and policymakers have turned their attention to operationalising the so-
