Component of risk

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The characteristics and circumstances of a community, system or asset that make it susceptible to the damaging effects of a hazard.

UNISDR Terminology (2009)

Vulnerability is one of the defining components of disaster risk.

What makes people vulnerable?

Vulnerability is the human dimension of disasters and is the result of the range of economic, social, cultural, institutional, political and psychological factors that shape people’s lives and the environment that they live in (Twigg, 2004).

Vulnerability can be a challenging concept to understand because it tends to mean different things to different people and because it is often described using a variety of terms including ‘predisposition’, ‘fragility’, ‘weakness’, ‘deficiency’ or ‘lack of capacity’.

Some definitions of vulnerability have included exposure in addition to susceptibility to harm. However, it is now understood that exposure is separate to the ‘susceptibility’ element of vulnerability since it is possible to be exposed, whilst at the same time not susceptible to natural hazards.

Despite some divergence over the meaning of vulnerability, most experts agree that understanding vulnerability requires more than analysing the direct impacts of a hazard. Vulnerability also concerns the wider environmental and social conditions that limit people and communities to cope with the impact of hazard (Birkmann, 2006).

Vulnerability is complex.

Vulnerability is not simply about poverty, but extensive research over the past 30 years has revealed that it is generally the poor who tend to suffer worst from disasters (Twigg, 2004; Wisner et al., 2004; UNISDR, 2009b). Poverty is both a driver and consequence of disaster risk (particularly in countries with weak risk governance) because economic pressures force people to live in unsafe locations (see exposure) and conditions (Wisner et al., 2004). Poverty and the other multi-dimensional factors and drivers that create vulnerability mean that susceptibility to the impacts of hazards is often, but not always, associated with certain groups, including women, children, the elderly, the disabled, migrants and displaced populations, amongst others.

Vulnerability relates to a number of factors, including:

Physical factors

e.g. poor design and construction of buildings, unregulated land use planning, etc.

Social factors

e.g. poverty and inequality, marginalisation, social exclusion and discrimination by gender, social status, disability and age (amongst other factors) psychological factors, etc.

Economic factors

e.g. the uninsured informal sector, vulnerable rural livelihoods, dependence on single industries, globalisation of business and supply chains, etc.

Environmental factors

e.g. poor environmental management, overconsumption of natural resources, decline of risk regulating ecosystem services, climate change, etc.

In addition, vulnerability is determined by historical, political, cultural and institutional and natural resource processes that shape the social and environmental conditions people find themselves existing within (IPCC, 2012). These processes produce a range of immediate unsafe conditions such as living in dangerous locations or in poor housing, ill-health, political tensions or a lack of local institutions or preparedness measures (DFID, 2004).

Many of the underlying drivers of vulnerability, including poorly managed urban development, are increasing, resulting in vulnerability increasing in many countries and regions of the world. While evidence suggests that wealthier, well governed countries are able to reduce disaster risks (UNISDR, 2009b, 2011, 2013), some countries have exhibited rapid economic growth in the last few decades without a commensurable rate of vulnerability reduction (UNISDR, 2015a).


Earthquake impacts in rural Kashmir


The Kashmir earthquake illustrates how poor rural livelihoods in remote areas configure mortality risk from earthquakes

SOURCE: UNISDR (2009b) [GAR09]


Social vulnerability in New Orleans


The failure of flood protection infrastructure, a failure to anticipate the disaster, and a badly managed response all exacerbated and magnified the pre-existing conditions of social vulnerability and racial inequality in New Orleans (Levitt and Whitaker, 2009; Tierney, 2006; Amnesty International, 2010; Masozera et al., 2007).

SOURCE: UNISDR (2015a) [GAR15]

Why does vulnerability matter?

By including vulnerability in our understanding of disaster risk, we acknowledge the fact that disaster risk not only depends on the severity of hazard or the number of people or assets exposed, but that it is also a reflection of the susceptibility of people and economic assets to suffer loss and damage. Levels of vulnerability (and exposure) help to explain why some non-extreme hazards can lead to extreme impacts and disasters, while some extreme events do not (IPCC, 2012). In the context of extensive risk in particular, it is often people’s vulnerability that is the greatest factor in determining their risk (UNISDR, 2009a).

In the context of different hazards, some groups are more susceptible to damage, loss and suffering than others and likewise (within these groups) some people experience higher levels of vulnerability than others (Wisner et al., 2004). Vulnerable groups find it hardest to reconstruct their livelihoods following a disaster, and this in turn makes them more vulnerable to the effects of subsequent hazard events (Wisner et al., 2004). Consequently, we have to reduce vulnerability in order to reduce disaster risk.

How do we measure vulnerability?

Vulnerability is complex. It has many dimensions, it is driven by factors at different levels, from local to global, and it is dynamic as it alters under the pressure of these driving forces (Twigg, 2004). Furthermore, the complex factors that make people vulnerable are not always immediately obvious.

The chain of causes of vulnerability, from the underlying drivers of vulnerability (e.g. socio-economic processes) to the immediate conditions that present themselves (e.g. poor quality housing), can be both long and complex; but by tracking it we can identify the progression of vulnerability that builds pressures on communities. These pressures can be released by taking measures to reduce vulnerability at various points along the causal chain (Twigg, 2004).

Owing to its different facets, there is no one single method for assessing vulnerability. Ideally, any assessment should adopt a holistic approach to assessing vulnerability. In reality, methods are usually divided into those that consider physical (or built environment) vulnerability and those that consider socio-economic vulnerability.

Assessing the vulnerability of the built environment to hazards is extremely important in assessing potential consequences of an event and for mainstreaming disaster risk reduction into the local development planning process. Understanding the response of existing structures to potential hazards, such as ground shaking from earthquakes and wind from tropical cyclones, requires the knowledge of building materials and engineering practices. This information base can only be reliably and sustainably developed at the local level (UNISDR, 2013).

Local engineers are increasingly dedicating themselves to understanding the vulnerability of their local building stock (which varies significantly from country to country and within countries) to different natural hazards. Engineers in the Philippines and Indonesia, for instance, are developing vulnerability calculations relevant to their own national building stocks. However these examples represent the exception. Likewise, opportunities for damage and loss data collection (critical to understanding futures risks) following disaster events continue to be missed (GFDRR, 2014a).

Efforts to quantify socio-economic vulnerability and poverty remain limited, and information of this kind is rarely integrated into risk assessments (GFDRR, 2014a). Quantifying social vulnerability remains a challenge, but indicators and indices to measure vulnerability have been created (quantified and descriptive), ranging from global indicators to those that are applied at the community level. These indicators are usually used to track changes in vulnerability over time. Qualitative approaches to vulnerability assessment have focused on the assessment of the capacity of communities to cope with natural events.

Vulnerability analysis involves understanding the root causes or drivers of vulnerability, but also peoples capacities cope and recover from disasters

At the community level, a number of researchers and humanitarian and development non-governmental organisations, as well as some local governments, have implemented vulnerability and capacity assessments (VCA), primarily through participatory methods. A VCA considers a wide range of environmental, economic, social, cultural, institutional and political pressures that create vulnerability and is approached through a number of different frameworks (Benson et al., 2007). According to Benson, VCA is typically applied as:

  • A diagnostic tool to understand problems and their underlying causes.
  • A planning tool to prioritise and sequence actions and inputs.
  • A risk assessment tool to help assess specific risks.
  • A tool for empowering and mobilising vulnerable communities.

By identifying their vulnerabilities and capacities, local communities identify strategies for immediate and longer-term risk reduction, as well as identifying what they can do themselves to reduce risk and where they need additional resources and external assistance.


The vulnerability of globalized supply chains


As supply chains become globalized, so does the vulnerability of businesses to supply chain disruptions, for example, when disasters affect critical production nodes or distribution links.


How do we reduce vulnerability?

Since we cannot reduce the occurrence and severity of natural hazards, reducing vulnerability is one of the main opportunities for reducing disaster risk. Vulnerability changes over time because many of the processes that influence vulnerability are dynamic, including rapid urbanisation, environmental degradation, market conditions and demographic change (DFID, 2004). Many of these factors are rooted in changing local conditions, but the picture is incomplete without acknowledging the national and global socio-economic and political structures that constrain local development opportunities. This means that a coherent fight against vulnerability needs to take place at three scales: the local, national and international (DFID, 2004).

Approaches to vulnerability reduction include:

  • Implementing building codes
  • Insurance and social protection (risk transfer)
  • Emphasising economic diversity and resilient livelihoods
  • Knowledge and awareness raising
  • Preparedness measures

Rather than focusing only on what limits people's ability to reduce their risk, the policy objective of disaster risk reduction (DRR) instead emphasises understanding people's capacity to resist and recover from disasters, as well as enhancing the overall resilience of people, society and systems. The local and traditional knowledge vulnerable communities possess to respond to disasters should form the basis of outside interventions to reduce disaster risk (Twigg, 2004).

Developing sustainable DRR capacities at national and local level requires that capacity locally generated, owned and sustained whilst also being the concern of society, rather than any single agency. Capacity development requires not only building technical capacities (such as environmental management) but also the promotion of leadership and other managerial and functional capacities. Finally, capacity development requires an enabling environment i.e. strong political ownership and commitment at the highest level (UNDP, 2010).


Stabilising livelihoods through participatory community based preparedness


Community-based preparedness and mitigation strategies can lower vulnerability and build resilience. By focusing on children the project minimised caste exclusion and made interest spread quickly throughout the community. Community participation was a key success factor, along with competent training staff, and networking with community-based organisations and the government.

SOURCE: World Vision – India (In partnership with World Vision UK, the Government of India and UNICEF) in UNISDR (2008)


Related Sections on Preventionweb

Components of Risk

Disaster Risk
Risk is a forward looking concept, so disaster risk can be understood as the likelihood (or probability) of loss of life, injury or destruction and damage from a disaster in a given period of time (adapted from UNISDR, 2015a).
A dangerous event that may cause loss of life, injury or other health impacts, as well as damage and loss to property, infrastructure, livelihoods and services, social and economic disruption and, or environmental damage is known as a hazard (UNISDR, 2009b).
The presence and number of people, property, livelihoods, systems or other elements in hazard areas (and so thereby subject to potential losses) is known as exposure (UNISDR, 2009b and IPCC, 2012).
The name given to the set of characteristics and circumstances of a community, system or asset that make it susceptible to the damaging effects of a hazard is vulnerability.

Risk Drivers

Climate change
Climate change can increase disaster risk in a variety of ways – by altering the frequency and intensity of hazard events, affecting vulnerability to hazards, and changing exposure patterns.
Environmental degradation
Environmental degradation is both a driver and consequence of disasters, reducing the capacity of the environment to meet social and ecological needs.
Globalized economic development
Globalized economic development can lead to increased exposure of assets in hazard-prone areas, leading to further increases in intensive risk if not managed.
Poverty & inequality
Poverty is both a driver and consequence of disasters, and the processes that further disaster risk related poverty are permeated with inequality
Poorly planned urban development
Whether or not disaster risk is factored into investment decisions in urban development will have a decisive influence on the future of disaster risk reduction.
Weak governance
Governance of disaster risk management must be improved, not only through specialized and stand-alone sectors, but also through strengthened governance arrangements across sectors and territories in order to address disaster risk.

Key Concepts

Capacity refers to all the strengths, attributes and resources available within a community, organization or society that can be used to achieve agreed goals.
Deterministic & probabilistic risk
Deterministic risk considers the impact of a single risk scenario, whereas probabilistic risk considers all possible scenarios, their likelihood and associated impacts
Direct & indirect losses
Direct disaster losses refer to the number of people killed and the damage to buildings, infrastructure and natural resources. Indirect disaster losses include declines in output or revenue and generally arise from disruptions to the flow of goods and services.
Disaster risk reduction & disaster risk management
DRR is the policy objective of anticipating and reducing risk. Although often used interchangeably with DRR, DRM can be thought of as DRR implementation, since it describes the actions that aim to achieve the objective of reducing risk.
Intensive & extensive risk
Extensive risk is used to describe the risk of low-severity, high-frequency disasters, mainly but not exclusively associated with highly localized hazards. Intensive risk is used to describe the risk of high-severity, mid to low-frequency disasters, mainly associated with major hazards.
Resilience refers to the ability of a system, community or society exposed to hazards to resist, absorb, accommodate to and recover from the effects of a hazard in a timely and efficient manner.
Sovereign risk
Sovereign risk is the economic impact a government would face in the event of a disaster.


Risk modeling
We need data on hazard, exposure, vulnerability and losses in order to understand and assess disaster risk.


Data and statistics are important in understanding the impacts and costs of disasters.
Data Viewers
Open access, online data viewers present hazard, disaster, and risk data in an easily accessible manner.