Vulnerability is broadly used to convey being susceptible to negative impacts (i.e. damage or harm) induced by some external stimuli – whether gradual changes or sudden extreme events – that thereby pose a threat.
Read the following articles for more on this:
Within the research domain there has long been a tendency to consider vulnerability to a single stressor. However in the last decade there has been a shift towards trying to understand vulnerability to multiple stressors in combination (see O’Brien et al 2004 for an early study of vulnerability to both climate change and globalisation across India) because this more accurately reflects lived experience and better explains autonomous adaptations that are undertaken. Taking a multi-stressor approach to vulnerability raises a number of challenges related to attributing causality, capturing vastly differing spatial and temporal scales, dealing with variable predictability in terms of the distribution and evolution of stressors, etc. To learn more about this evolution in vulnerability research, current challenges in vulnerability analysis and integrated approaches being developed read the excellent review paper published in 2006 by Hallie Eakin and Amy Luers.
In most cases climate change is not a single stressor but rather a set of multiple climatic stressors specific to the location in question, for example a combination of prolonged hot spells, intensifying rain events, delays in the onset of the rainy season, rising sea levels, etc. Such climate stressors often in turn manifest in concert with other environmental and non-environmental stressors, such as deforestation, pollution of water bodies, overfishing, national political instability, regional in-migration, international financial crises, etc. Distinguishing the relative important of stressors in driving a particular outcome / impact, e.g. a shortage of water for domestic use, is an ongoing methodological challenge.
Decisions about which stressors to consider when assessing vulnerability are context specific and are tied to decisions about whose or what’s vulnerability is being assessed e.g. a bounded socio-ecological system, an ecosystem, households within a village, livelihood groups, an administrative district, etc. It is important to be explicit and transparent when considering and documenting or communicating these decisions so that people can consider the implications of these decisions is relation to the findings of the assessment.