Assessing Human Vulnerability to Climate Change from an Evolutionary Perspective - Reducing Disaster: Early Warning Systems for Climate Change - page 62

of climate change are expected to occur over the medium to long term, and a system's
ability to adapt to those changes can alter its vulnerability a great deal. From an
evolutionary perspective, adaptation is driven by human agency - the behaviour,
creativity and entrepreneurialism of individuals and organizations. However, it is
also structured by socio-economic, ecological and historical factors. To fully under-
stand how human systems adapt to changing climatic conditions, an evolutionary
approach to vulnerability assessment would examine how structure and agency
interact to create locally specifi c vulnerability trajectories.
Section 4.3 discusses the various methods that have been employed to identify and
measure vulnerability within human systems. It describes the evolution from impact
assessments that employ economic modelling to vulnerability assessments that involve
quantitative and/or qualitative empirical research. We argue that from an evolutionary
perspective, qualitative research methods are necessary to capture the complex and
structural elements of vulnerability in a manner useful for decision-makers.

4.2 Vulnerability: The Concept

In its Third Assessment Report, the Intergovernmental Panel on Climate Change
(IPCC) defi ned vulnerability to climate change as “a function of the character, mag-
nitude, and rate of climate variation to which a system is exposed, its sensitivity, and
its adaptive capacity” (Smit and Pilifosova 2001 ). This function is expressed in
shorthand in Eq. 4.1 (Adapted from Yohe and Tol 2002 ):

{ }

()()

A ; ( 4.1 )
where, V denotes vulnerability , as defi ned above; E denotes exposure , the likeli-
hood of the human system being affected by a natural event, or climate stimulus; S
denotes sensitivity , degree to which a system would be affected by the exposure;
and A denotes adaptive capacity, the ability of human systems to adjust to actual or
expected changes in climatic stimuli.
Note that in this defi nition, vulnerability is not only a function of the exogenous
variable exposure ; it is also a function of the endogenous variable sensitivity .
Whereas exposure is determined by characteristics of the climate (i.e. the magni-
tude and duration of climate stimuli), sensitivity is determined by the occupance
characteristics of the human system in question, the social, economic, cultural,
political and institutional factors that determine how a system will be impacted by a
climate stimulus (Smit and Wandel 2006 ).
The fi nal dimension of vulnerability is adaptive capacity . Over time, human sys-
tems are thought to gradually adapt to local environmental and climatic conditions.
As depicted in Eq. 4.1 , adaptive measures can conceivably modify both a system's
sensitivity and its exposure. For example, “Vaccination against climate sensitive
vector-borne diseases and EWSs for heat waves are examples of adaptation mea-
sures that reduce the sensitivity and exposure of people to climate-related health
hazards, respectively” (Füssel and Klein 2006 ).

VFE = S