II. Risk, Vulnerability and Capacity
II.2 Components of Risk
Disasters signify unmanaged risks (Westgate, O’Keefe 1976). Thus, a hazard event is not the only driver of disasters. Disasters are to a large part socially constructed, rooted in the exposure and vulnerable conditions of societies to natural phenomena, such as extreme hazardous events (UNISDR 2004; Cardona 2011; Birkmann 2006c). Thus, R&V research in the context of socio-natural disasters deals on the one side with the spatial and temporal analysis of the physical phenomena of extreme events, and on the other with employing theories, concepts and methods for understanding those conditions in the human and environmental system that determine whether a hazard turns into a disaster. This notion is reflected by the term
“vulnerability”. It focuses on structures and processes of a socio-ecological system which can increase the magnitude of disaster impact or prevent disasters (Bohle, Glade 2008). Hence, society is viewed as agency of shaping R&V by contributing to the transformation of physical
events into hazards that increase the likelihood of adverse effects (Chambers 1989; Wisner et al. 2004). Hence, Weichselgartner (2001) acknowledges that social sciences and natural sciences approaches in disaster research should not only coexist, but be integrated to better understand their mutual causal relationship (Weichselgartner 2001). Thereby, research also shall consider that parameters of hazard characteristics as well as those of vulnerability change dynamically over time, hence, that also R&V is not fixed but is a continuum in constant evolution (ICSU-LAC 2010). In the following a more detailed description of the constituent elements of risk, namely hazard, exposure, and vulnerability is provided.
II.2.1 Hazard
A hazard refers to “a dangerous phenomenon, substance, human activity or condition that may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage“ (UNISDR 2009a). Until recently, the term risk was used to pinpoint at the requirement to describe certain hazard characteristics. Today, acknowledging the contributing role of vulnerability to overall disaster risk conditions, hazard is considered only as a component of risk (Cardona et al. 2012, p. 69).
Hazard research is dealing with understanding the different physical conditions and processes of hazard generation and their magnitude and frequency / probability of occurrence as well as their spatial and temporal distribution. Specific concerns of hazard research are to determine thresholds, at which a “natural system” alters and significantly increases disaster risk (Bohle 2008). Against the background of humankind’s increasing role in degrading ecosystems and exploiting natural resources, hazards are not anymore purely of natural origin, they are socio-natural hazards. For example, deforestation can become an important trigger for landslides, floods and droughts (Lavell 1999). The following graph illustrates the “spectrum of hazards”
that can be triggered, either by purely natural factors or a mix of human-natural factors and processes (Cf. Figure 2)
Figure 2 Hazards of natural and socio-natural origin
II.2.2 Exposure
Exposure can be referred to as a “first order R&V condition” - defined by UNDP as the
“Elements at risk, an inventory of those people or artefacts that are exposed to a hazard”
(UNDP 2004) - in which societal structures, people and the environment can potentially be adversely affected by a hazard event simply because they are physically located in a hazardous area. Thus, exposure is a function of both, the hazard potential and the existence of an element of concern in the catchment of the hazard. Without a hazard threat, or a hazard threat without elements of concern in the catchment of a hazard, there is no exposure. Thus, exposure is a precondition for deeming an area as a high risk area, but not a sufficient risk factor. Disaster impacts vary for different elements exposed to a given hazard. Some of those exposed suffer harm, some rather not. The conditions that configure the likelihood of suffering harm are to be found in vulnerable conditions. To conclude, it is possible to be exposed but not vulnerable, but in order to be vulnerable, exposure is a necessary precondition (Cardona et al. 2012).
II.2.3 Vulnerability
In its very basic form vulnerability can be described as the likelihood to be wounded (Turner et al. 2003), or more elaborated, the propensity of exposed elements such as physical or capital assets, as well as human beings and their livelihoods, to experience harm and suffer loss and damage by a single or a compound of hazard events (UNDRO 1980; Cutter, Finch 2008; Cutter et al. 2003; Birkmann 2006c; Chambers 1989; Liverman 1990; Timmerman 1981; Birkmann 2006a) Often the terms exposure and vulnerability are used interchangeably (Cardona et al.
2012). This is a serious pitfall (fallacy), because simply looking at exposure may overlook the underlying causes of adverse disaster impacts, the so-called „vulnerabilities“. In its infancy, the research on vulnerability had been limited to understand the lack of physical resistance of engineering structures (UNDHA 1992). But as vulnerability is highly contextual (O'Brien et al.
2007), today`s vulnerability has become multi- and transdisciplinary (IPCC 2012), and is at home in the social sciences, ecology, economy, public health, poverty and development, livelihoods and famine, and climate change adaptation. It focuses on the characteristics of historical and prevailing cultural, physical, social, environmental, political, and economic contexts and processes that lead to societies` vulnerability to environmental threats (Watts, Bohle 1993;
Bankoff et al. 2004; UNISDR 2009b; Luers et al. 2003; IPCC 2007, (Schröter et al. 2005)).
Because of the multidisciplinary perspective, vulnerability is defined2 and conceptualized in many different ways, each claiming to use the most appropriate terms, such as susceptibility, fragility, sensitivity, weaknesses, deficiencies, or lack of capacities (Cardona et al. 2012;
Villagrán De León 2006; Füssel 2007; Wisner et al. 2004; Cutter et al. 2003). But all share the view that vulnerability is socially constructed and the outcome of a complex set of drivers and interacting conditions that increase the likelihood of adverse impacts of natural and socio-natural hazards on the human or environmental system (UNDRO 1980; Cannon 2006; Wisner et al. 2004; Weichselgartner 2001; Bogardi, Birkmann 2004; UNISDR 2004, 2009b; Birkmann 2006a; Janssen, Ostrom 2007; Thywissen 2006).
2 General definitions and reviews on the issue of vulnerability are provided by Thywissen 2006; Kasperson, Kasperson 2005.