Vulnerability of a system refers to its physical, social, and economic aspects.
According to IPCC, vulnerability is a function of the character, magnitude and rate of climate variation to which a system is exposed; its sensitivity; and adaptive capacity (IPCC, 2001).
From the above definition, we can note that IPCC uses three terms to define vulnerability â€“ exposure, sensitivity, and adaptive capacity. Let us know more about these terms.
Click each term to view its detail.
Exposure is defined as â€˜degree of climate stress upon a particular unit analysis; it may be represented as either long-term changes in climate conditions, or by changes in climate variability, including the magnitude and frequency of extreme eventsâ€™ (IPCC, 2001).
There are two main elements to consider in exposure.
- Things that can be affected by climate change (populations, resources, property, and so on)
- The change in climate itself (sea level rise, precipitation and temperature changes, and so on)
You can watch a video on â€˜Adelaide Nowâ€™ to understand how sea level rise in the island-nation of Tuvalu makes it extremely vulnerable to climate change.
Sensitivity is the degree to which a system will be affected by, or responsive to climate stimuli (Smith et al., 2001).
Sensitivity is basically the biophysical effect of climate change; but sensitivity can be altered by socio-economic changes. For example, new crop varieties could be either more or less sensitive to climate change.
- Adaptive Capacity
Adaptive capacity refers to the potential or capability of a system to adjust to climate change, including climate variability and extremes, so as to moderate potential damages, to take advantage of opportunities, or to cope with consequences (Smit and Pilifosova, 2001). As the name suggests, adaptive capacity is the capability of a system to adapt to impacts of climate change.
Smit et al., 2001, have identified the following seven factors that determine adaptive capacity.
- Social capital
Hence, vulnerability is a function of all the three terms.
Mathematically, this can be denoted as
Vulnerability = f (Exposure, Sensitivity, Adaptive Capacity)
In other words, the greater the exposure or sensitivity, the greater is the vulnerability. However, adaptive capacity is inversely related to vulnerability. So, the greater the adaptive capacity, the lesser is the vulnerability.
Therefore, reducing vulnerability would involve reducing exposure through specific measures like building a dyke in case of sea level rise, or increasing adaptive capacity through activities that are closely aligned with development priorities.
The table below is an example of the effect of climate change on livelihoods, and illustrates how interplay of these impacts affects the vulnerability of the system.
Changes in mean climate, variability, extreme events and sea level rise
Effects on livelihoods
Impact on vulnerability
Increased temperature and changes in precipitation reduces agricultural and natural resources
Changes in precipitation run-off and variability leads to greater water stress
Increased incidence or intensity of climate related extremes such as water stress
Temperature, water and vegetation changes resulting in increasing prevalence of disease
Direct impacts of climatic shocks and stresses such as livelihood assets, health, food and water security
Increased pressure on Coping strategies and social protection measures
Reduced ability recover due to increased frequency of climatic shocks or increased intensity of climatic stresses
Increased vulnerability due to:
- Lower capacity to prepare;
- Lower capacity to cope; and
- Lower capacity to recover from climatic and non-climatic shocks and stresses
Source: DFID, 2004
We will now study the factors that determine vulnerability.