Vulnerability and risk assessment

The drought risk impacts are proportional to the level of vulnerability and the degree of drought in a region.

Why a risk assessment is important?

A risk assessment provides important information that helps define priorities and develop actions that prevent drought from escalating into a disaster and mitigate its impacts. The assessment can also help identify vulnerable locations where the impacts of drought are or expected to be most severe, so that authorities can direct drought preparedness, mitigation and crises response actions to the most vulnerable communities and sectors. Vulnerability and risk assessments should be well-coordinated and consistent to ensure informed decision making and drought risk mitigation intervention priorities, as explained in pillar Three of the Drought Toolbox. Results of the assessment should be incorporated into land use and rural development planning, health care systems, environmental and natural resource management approaches to supply chains and business models, and agricultural as well as non-agricultural sectors.

How does a drought risk assessment fit into a National Drought Plan?

Understanding and assessing drought vulnerability should take into account that various sectors, population groups and regions of a country can be more vulnerable than others or vulnerable in different ways. A National Drought Plan should include a risk assessment to ensure that preparedness, response and drought mitigation activities are effective, efficient and targeted at those who need them most.

The UNCCD 2018-2030 Strategic Framework includes a new strategic objective (SO3) on the consideration of drought in national action programmes. With particular reference to vulnerability and impact assessment, the COP 13 decision 29 focused on the opportunities for the Parties to consider completing assessments for sectors, population groups and regions vulnerable to drought.

What is included in this drought risk assessment?

Here, drought risk is calculated as the probability of harmful consequences or likelihood of losses resulting from interactions between drought hazard (for example, possible future occurrence of drought events), drought exposure (such as the total population, its sources of livelihood and assets in an area in which drought events may occur) and drought vulnerability (for example, the propensity of exposed elements to suffer adverse effects when impacted by a drought event) (Carrão et al. 2016). Drought risk is calculated by using the following formula:

Drought risk = Vulnerability x Hazard x Exposure

Each component of drought risk is calculated independently of each other, based on global-scale indicators of different spatial resolutions.

• Hazard has been established by using historical sequences of monthly precipitation deficits for the period between 1901 and 2010
• Exposure has been computed at the sub-national level using high spatial resolution gridded indicators of population and livestock density, crop cover and baseline water stress
• Vulnerability has been derived from a combination of factors of social, economic and infrastructural indicators