Dr Bapon (SHM) Fakhruddin is Technical Director – DRR and Climate Resilience. He is an international disaster risk reduction and hazard modelling expert who is a regular adviser to the United Nations on Natural Hazards and Climate Change.
In general, climate change scientists frame vulnerability and risk in a wider spatial context. This means that most climate risk studies are carried out at a national or regional scale. Due to the nature of the processes studied by the climate change community, it is not feasible and even senseless to assess vulnerability at detailed scales, something that is quite common in the natural hazards community.
Assessments of vulnerability and risk of extreme weather or climate events are essential to inform and implement appropriate prevention, adaptation and mitigation strategies. Due to the complex nature and uncertainties of future climate change projections, it is not feasible to assess vulnerability at detailed scales for extreme weather events. When aiming to understand the assessment of hazard, exposure, vulnerability and risk, there are two extreme operating scales, a global (e.g. in terms of climate change) and a local (e.g. in terms of natural hazards). Different approaches and methods exist for conducting hazard, exposure, vulnerability and risk assessments, but often they are notable to address all aspects of physical science, engineering, and social science research.
Vulnerability and risk terms have different definitions explaining their meaning and are used differently in many assessments. Looking at the IPCC AR5 (IPCC, 2014) and AR4 (IPCC, 2007) approach, there is a difference in explaining vulnerability and risk. In AR4 and in AR5, only the combination of all components allows us to draw a complete picture leading to the final results called ‘vulnerability’ in AR4 and ‘risk’ in AR5. Whereas both concepts identify components leading to negative consequences caused by the effects of climate change and climate-related extremes on natural or social systems. Exposure has been removed from the definition of ‘vulnerability’ in AR4 as it is included in the definition of ‘risk’ now in AR5. Looking at another perspective, for example, natural scientists and engineers tend to apply the term in a descriptive manner associated with a quantitative outcome, whereas social scientists tend to use it in the context of a specific explanatory model. Sovacool et al., (2012) defines vulnerability as the consequences of the impact of a natural force, and not to the natural process or force itself. Social vulnerability includes the demographic issues that social groups carry with them and that makes them susceptible. Biophysical vulnerability is the distribution of hazardous conditions that stem from “initiating events” – like hazards.
The IPCC AR5 framework does not specify how to operationalise a climate risk assessment. Therefore, there is no one standard approach or formula for assessing risk resulting from the consequences of climate change. That is why there are countless approaches to risk assessment. Nevertheless, risk can be considered as a dynamical process concerning time, and it can be derived basically from the convolution of three main components (UNDRR, 2019; IPCC, 2014; UNISDR, 2016; UNU-EHS, 2006) (equation 1)
Risk (R) = ƒ (Probability of a Hazard (p),* Exposure (E), * Vulnerability (V)) —–(1)
• Hazards are considered as ‘process, phenomenon or human activity that may cause loss of life, injury or other health impacts, property damage, social and economic disruption or environmental degradation’ (UN, 2016).
• Exposure is ‘presence of people, livelihoods, species or ecosystems, environmental functions, services, and resources, infrastructure, or economic, social, or cultural assets in places and settings that could be adversely affected by natural hazards and climate change’ (IPCC, 2014, Annex II).’
• The vulnerability term represents ‘The predisposition to be adversely affected. Vulnerability encompasses a variety of concepts and elements, including sensitivity or susceptibility to harm or damage, and lack of capacity to cope and adapt (adaptive capacity) (IPCC, 2014, Annex II)”.
• The term “risk” has different meanings: (a) as a synonym for probability of a harmful effect occurring and (b) as a synonym for the mathematical expectation of the magnitude of the undesirable consequence (even as a quasi-synonym of consequence, whereby risk has a similar meaning to an undesirable outcome) (UNDRR, 2019).
Being aware of exposure and vulnerabilities, researchers can better predict the degree of potential consequences or impacts. There is no consensus on how to measure and combine the various intrinsic components of risk, but whatever model is used to represent it, the result should be the same in the end.
Assessing the risk of potential hazards from climate change drivers on a community is vital to understanding how to adequately prepare, cope, adapt or mitigate. There are many different approaches and methods readily available for performing a risk assessment. A risk assessment should take consideration of hazard, exposure and vulnerability into account; however, these elements are often challenging to quantify and define. Risk assessments utilising hazard-exposure-vulnerability framework enable consideration of the inherent vulnerability of infrastructure or population, rather than only focusing on the potential impacts of an event. At the same time, climate risk assessment has a valuable aspect of adapting and building resilience and acknowledging and addressing uncertainty.
Tools, Approaches and Methods for Climate Risk and Vulnerability Assessment
Research from the past two decades indicates that innovative tools are required for hazard, exposure and vulnerability assessment to support understanding and assessing vulnerability and risk (Erich et al., 2018; IPCC 2014; McEntire, Gilmore, & Peters, 2010; Susman, O’Keefe, & Wisner, 1983). Although different tools currently exist for running an integrated and dynamic assessment of risk and vulnerability, the choice of such tools is important as it directly relates to the aims of the assessment itself. McEntire, et al.,(2010) suggested a vulnerability model that incorporates physical science, engineering, and social science research and also concluded that a “more complete view of vulnerability is more appropriate to generate inclusive and integrated disaster policies”. Climate risk assessments provide a picture of prioritized risks based on different scenarios, connection to existing adaptation and resilience processes, enabling available response capacity and resources to be targeted more effectively and addressing uncertainty. The overall climate or natural hazards risk assessment scheme is shown in the image below.
Certain principles could be set-up for risk assessment approaches, such as qualitative or quantitative approaches, stakeholders’ engagement, estimation of consequences/impacts and their knock-on effects (second, third order, etc.) and also cross-sector engagement, dealing with uncertainty, transparency in decision making, etc.
Risk assessment should take into account all the elements: hazard, exposure and vulnerability, but, it is challenging to quantify and define all these features. Furthermore, the mutual interaction between each element is not linear and well-known, and all these dimensions are emphasized in the risk management of extreme weather because they are related to low-probability events with potentially high consequences. For probabilistic disaster risk assessment, the vulnerability of exposed elements is assessed using functions that relate to the intensity of the hazard phenomenon to the mean damage ratio or direct physical impact. The probability and severity of the hazard are not the only factors that affect risk. Risk also depends on the exposure to the hazard and how vulnerable it is to damage.
Conclusion
In general, climate change scientists frame vulnerability and risk in a wider spatial context. This means that most climate risk studies are carried out on a national or regional scale. Due to the nature of the processes studied by the climate change community, it is not feasible and even senseless to assess vulnerability at detailed scales, something that is quite common in the natural hazards community. This poses an interesting paradox: ‘On the one hand reducing the vulnerability of local communities to natural hazards needs to take into account climate change, on the other hand, the most effective vulnerability reduction often takes place locally’ (Schipper & Pelling, 2006). When aiming to understand the operation of vulnerability concepts, these two extreme operating scales, global (mostly in climate change) and local (mostly in natural hazards), are not so adequate. The key, in our opinion, is to aim for an intermediate scale of complexity.
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Reference:
This is a synthesis of a paper published in “Climate Extremes and Their Implications for Impact and Risk Assessment” (2019). Edited by Jana Sillmann, Sebastian Sippel and Simone Russo. Paper on Bapon Fakhruddin, et al. (2019), Assessing Vulnerability and Risk of Climate Change, Climate Extremes and Their Implications for Impact and Risk Assessment.
