Climate Risk and Vulnerability Assessment

Not every weather extreme has to become a disaster

Climate Risk Analysis and Vulnerability Assessment (CRAVA) is a framework to identify which regions, communities, or value chains are most at risk from climate hazards like droughts, floods, or heatwaves. It acknowledges that a weather extreme only becomes a disaster if lives and livelihoods are exposed to it, and if there is low capacity to deal with the impacts.

For example:

• A farmer without access to accurate weather information is more likely to lose crops to sudden storms and heavy rainfall.
• Rain-fed agriculture is more vulnerable during dry spells compared to irrigated farms.
• Improper harvest storage increases losses from wind gusts and extreme weather.

This is the basis of Climate Risk Analysis and Vulnerability Assessment (CRAVA) – also known as Climate Risk Assessment (CRA) or Climate Risk and Vulnerability Assessment (CRVA). It helps decision-makers prioritize climate adaptation strategies by pinpointing the factors that contribute most to climate risk. Climate risk is a function of the climate hazard, exposure, and vulnerability:

Risk = Hazard × Exposure × Vulnerability

• Climate hazards are physical events such as extreme weather events that are driven by our current climate. Most hazards are changing in severity and frequency due to anthropogenic climate change.
• Exposure refers to the presence of people, infrastructure, or assets such as crops that could be affected by the hazard. In other words, exposure relates to the “what” and “where”.
• Lastly, vulnerability is a measure of the intrinsic susceptibility of exposed elements to harm, considering both sensitivity as well as capacity to adapt, cope, or recover. Vulnerability factors can be physical, social, financial, gender-sensitive, or systemic.

How does climate risk analysis work?

CRAVA will locate the regions and assets that are most at climate risk, as well as determine which element is contributing most to the risk being high. This can then help to identify the optimal climate adaptation strategy for the affected value chain or marginalised community in a specific area.

How can climate risk assessments help governments and NGO’s?

Climate risk assessments will provide governments, NGOs, and other stakeholders with the right tools to take adaptation measures or allocate funds.  This way they contribute to stronger and more resilient communities.

How to adapt to high-risk situations?

For example, when risk is high due to recurring droughts, a strategy can be to invest in the dissemination of drought-resilient crops and seed varieties. Or when widespread flooding is a source of high risk, a community can decide to build dykes and flood protection to reduce exposure. When vulnerability is the crucial factor contributing to high risk, government policies should prioritize poverty reduction, conflict resolution, health infrastructure, or all-season road access.

Weather Impact’s tailored CRAVA method

The Weather Impact team has developed a Climate Risk Analysis and Vulnerability Assessment (CRAVA) method, based on the IPCC Climate Risk framework, which can be accustomed to specific countries and to various value chains. We can select a different combination of hazards, exposed elements, and vulnerability factors, to quantify climate risks and to arrive at a tailor-made risk assessment for the stakeholders involved.

Fig.1 Weather Impact’s CRAVA method, based on IPCC framework.

Which steps are crucial in climate risk and vulnerability assessments?

The Weather Impact CRAVA framework consists of four key steps:

1. First, we identify the main climate hazards (e.g. erratic rainfall variability, drought, wildfires) and quantify the level of threat from each of these. We start from either historical (f.e. ERA5) or future (CMIP6, different SSP scenarios) climate data such as temperature and precipitation and transform this into gridded hazard layers through tested statistical methods. Additionally, we consider a multi-hazard layer which combines the threat level of all single hazards, to identify compounded hazards.
2. The next step is to quantify the exposure of key value chains to the hazards. The definition of exposure depends fully on the assets that should be considered. For example, we use physical crop area for agricultural value chains. The (normalised) exposure layer is multiplied by the hazard layers to obtain the exposure score, which is a relative measure of the magnitude of assets that are exposed to each hazard.
3. Next, we assess the vulnerability of relevant sectors and actors. Vulnerability is defined as the ratio between sensitivity (intrinsic susceptibility to hazards) and adaptive capacity (the ability to absorb and recover from shocks). These can be crop-specific (e.g. level of irrigation), socio-economic pressures (e.g. poverty level), enabling services (e.g. proximity to water, sanitation, and health or WASH services), or physical infrastructure (e.g. access to roads and markets).
4. The final step is to calculate the risk score by multiplying the exposure score with the vulnerability. The risk scores are normalized indices (0 meaning no risk and 1 meaning highest risk), per single- or multi-hazard, in the current and future climate, and per value chain.

We can do additional risk analysis:

• Quantifying the potential of risk amplification (e.g. by additional hazards),
• Pinpointing fragility hotspots (e.g. where climate risk, conflict, and food insecurity can lead to cascading impacts),
• Identifying the factor that has the highest risk-reducing potential (for prioritization of the most effective adaptation strategy).
• Diagnosing gender-aggregated risk, for example through census data on woman-led agricultural households.

Examples of projects where we employ CRAVA

• Climate risks to maize, rice, and soybean assets in Northern Nigeria https://www.weatherimpact.com/products/nigeria/
• Resilient maize-soybean-poultry value chain in five provinces in Mozambique weatherimpact.com/products/mozambique/
• Compounding risk to sorghum, maize, rice, sesame, and fisheries in South Sudan https://www.weatherimpact.com/products/south-sudan/
• Climate challenges to the agricultural sector in Cameroon https://www.weatherimpact.com/products/cameroon/

Example: Climate risk of fisheries sector in South Sudan

One project where we assess climate risk and vulnerabilities is a technical support for climate adaptation solutions in South Sudan. First, we identify the major climate-related threats to the fisheries value chain: droughts, flooding, heat stress, and erratic rainfall. Then, we define river and wetlands area, together with census-data on number of fishers per state, as exposure layer. Lastly, we combine this with country and value chain specific data on vulnerabilities to compute the risk scores. These climate risks scores (Figure 2) are calculated per hazard type and are specific for the fisheries value chain. Our assessment tells us that the main risks to the fisheries sector in South Sudan is coming from drought and heat stress. This information will help us to inform adequate climate adaptation strategies.

Fig.2 Climate risk scores for the fisheries sector in South Sudan to (a) droughts, (b) flooding, (c) heat stress, and (d) changes in rainfall variability, based on historical data from 1995 – 2015. Red means a higher risk. The blue regions are the specific counties of interest to our project.