Understanding disaster risks to agriculture and food security
Understanding disaster risks and exposure is fundamental for policy formulation, planning, and decision-making in agriculture. This chapter outlines examples of risk assessment and analysis tools that complement climate change impact scenarios (see module C8). Given that effective strategies can only be achieved by understanding the disaster risks that farmers are already facing, these tools can also support planning for climate change adaptation and climate-smart agriculture.
Building resilience of livelihoods to shocks demands that stakeholders “grasp the dimension of multiple challenges” (High-level Panel on Global Sustainability, 2012). An examination of the diversity of natural hazards affecting agriculture and food security indicates that, even without climate change, many hazards are already eroding livelihoods and compromising gains made in food security. These hazards add to the challenge of reaching Sustainable Development Goal 2: “End hunger, achieve food security and improved nutrition and promote sustainable agriculture.” Along with climate-related hazards, other natural hazards, such as earthquakes, tsunamis and volcanic eruptions, and human-induced hazards, such as conflict, economic crises, high food prices must also be taken into account. Examples described below of large-scale disasters caused by climate-related hazards highlight the magnitude of their impacts and the different types of recurring disaster risks.
In 2010, Pakistan experienced the worst flooding in over 80 years. Over 20 million people were affected. Heavy rains during the 2011 monsoon season caused renewed and devastating flooding that affected almost 10 million people (World Bank and Asian Development, 2010). Over 70 percent of farmers lost more than half of their expected income. The floods caused USD 5 billion in damage and losses to the agriculture sectors (FAO, 2015). In 2012, over 18 million people faced food insecurity in the Sahel region of West and Central Africa (FAO, 2012a; FAO, 2012b). In 2013, 2015 and 2016 several tropical cyclones had devastating effects on a number of countries, for example Typhoon Haiyan in Philippines, Cyclone Pam in Vanuatu and Winston in Fiji, Hurricane Mathew in Haiti. Typhoon Haiyan alone affected 14.1 million people, and caused damage and losses of about USD 1.4 billion (FAO, 2015). In 2015, the Nepal earthquakes affected millions of people in a total of 39 districts, out of 75 districts countrywide. In all these events, the impacts on food security and agricultural livelihoods were extremely high. Millions of hectares of standing crops were damaged. Families lost livestock, crops, food stocks and agricultural inputs. Markets were disrupted, and damaged infrastructure constrained the delivery of emergency assistance.
Climate change will increase the frequency and intensity of extreme weather events. It will also have slow onset impacts. All of these impacts, raise the probability of some countries becoming trapped in chronic crises situations. These crises can vary in their nature and complexity. In 'simultaneous crises' different hazards occur at the same time; in ‘sequential crisis’ hazards trigger series of cascading disasters; and in ‘synchronous failures’ different hazards converge and interact (FAO, 2008). It is becoming increasingly challenging to ensure food security in the face of multiple hazards and the impacts of climate change.
C5 - 2.1 Mapping multiple risk and vulnerabilities
The assessment of threats to agriculture is a necessary first step in designing effective risk reduction measures to safeguard food security. Multi-hazard risk and vulnerability assessments are vital to ensure sound decisions are made about disaster risk reduction and climate-smart agriculture. These assessments are needed not only for risk reduction and adaptation planning, but also for risk-informed sustainable intensification of production and the implementation of potential climate change mitigation measures.
Hazard maps delineate the geographic areas exposed to a specific type of hazard. Typically, they indicate the likelihood of the hazard's occurrence, the frequency and its potential severity. Hazard maps are based on historical data and knowledge of past events.
Vulnerability mapping identifies the elements (e.g. populations, property, agricultural areas, livelihoods, services, health facilities) that are exposed to hazards and that may be adversely affected them. Vulnerability assessments also include social or economic dimensions, including livelihoods.
Risk is determined through the combined analysis of potential hazards and existing conditions of vulnerability. Hazard and risk maps can be developed at different spatial scales to display how risks are distributed across a given geographical area. These maps can be site-specific, encompass municipal or provincial administrative areas and subnational landscapes (e.g. river basins), or they can be national and even regional in scope.
Methodologies and tools used for hazard and risk assessment and mapping vary considerably, but some of the most advanced follow an all-hazards, all-risks approach. This approach makes it possible to assess the cumulative consequences of hazards and their interactions. For instance, some areas may be prone to drought during the dry season, but also to floods during the rainy season. This has important implications for the design of appropriate measures for disaster risk reduction and climate-change adaptation. Figure C5.2 provides an example of the comprehensive multi-hazard risk assessment framework used in Nepal to guide risk reduction measures.
Figure C5.2. Nepal risk assessment and mapping framework
The framework, which includes a national assessment of hazards, including of earthquakes, floods, droughts and landslides, is based on historical information, with maps indicating the spatial distribution of hazards in the country. The assessment was followed by an analysis of exposure, vulnerability and risk for various physical, social and infrastructural assets, including those related to the agriculture sectors.
The application of risk assessments for various planning objectives is growing. Disaster risk assessments are used in land-use planning and territorial development, investment planning, urban planning, the design of public infrastructure, scenario analysis, disaster preparedness and climate change adaptation.
C5 - 2.2 Combining risk assessment and climate change scenarios
Integrated landscape management requires an understanding of all natural hazards and risks affecting a given landscape and an assessment of the potential impact of climate change on agricultural ecosystems. This approach provides evidence-based geographic assessments of current disaster risks and future climate change scenarios that can be used to help countries design holistic climate-smart agriculture policies, strategies, and practices at the national or local level (see also module A3 on integrated landscape management). To give planners short-, medium- and long-term perspectives when designing and implementing appropriate measures, it is necessary to develop a harmonized framework that uses computer modelling to integrate data and analysis of natural hazards with projected climate change scenarios (see also module C8 on assessments for climate-smart agriculture policy). An example of such an approach can be found in a pilot project from Jamaica, which is illustrated in Box C5.2.
Box C5.2 Jamaica - the Risk and Vulnerability Assessment Methodology (RiVAMP)
The Risk and Vulnerability Assessment Methodology (RiVAMP), piloted in Negril on the west coast of Jamaica (Figure C5.3), is an evidence-based assessment tool that assists national and local decision-makers in making informed choices that can reduce risk and support sustainable development through improved ecosystem management. RiVAMP, which takes into account climate change factors, was designed particularly for land-use and spatial development planners, and key stakeholders involved in natural resource management and disaster risk management.
The project examined the impacts of tropical cyclones and their secondary effects, particularly storm surges and flooding, as well as the potential impacts of rising sea levels. Environmental features were analysed to determine the extent to which coral reefs and sea grasses serve as a natural protective barrier against storm surges and rising sea levels.
RiVAMP used a blend of proven scientific methods, including risk mapping with the use of the Geographic Information System (GIS); satellite imagery analysis and other remote sensing techniques; and statistical analyses and modelling of buffering effects of coral and sea grass. The science-based analysis was complemented by stakeholder interviews and consultation workshops.
Figure C5.3. Maps of Negril pilot area: Map of Negril pilot area, and flood hazard map 50-year return period exposure for a) population and b) assets
GIS mapping and analysis, which included population distribution, infrastructure and other exposed assets, assisted in calculating the exposure to storm surges and flooding associated with tropical cyclones (Figure C5.4). Remote sensing used high-resolution satellite images and aerial photographs from 1968 to determine the types and distribution of coral and sea grasses. These images and photographs were also used in the analysis of coastline erosion due to tropical cyclones and rising sea levels. An ensemble of six widely-used, numerical models were applied to assess the range of shoreline retreat of Negril beaches under various rates of sea level rise and storm surges. Multiple regression analyses were used to identify the positive influence of coral reefs and sea grass meadows on the beach erosion patterns along the Negril coastline.
Figure C5.4. Distribution of coastal ecosystems and locations of the profiles used for the multiple regression analysis
GIS mapping and analysis assisted in the computation of exposure to storm surge and flooding associated with tropical cyclones. The analysis included population distribution, infrastructure and other exposed assets. Remote sensing used high resolution satellite images and aerial photographs from 1968 to determine the types and distribution of coastal ecosystems, especially coral and sea grasses. These images and photographs were also used in the analysis of coastline erosion due to tropical cyclones and rising sea levels. An ensemble of six widely-used, numerical models were applied to assess the range of shoreline retreat of Negril beaches under various rates of sea level rise and storm surges. Multiple regression analyses were used to identify the positive influence of coral reefs and sea grass meadows on the observed beach erosion patterns along the Negril coastline.
Estimations based on global projections of long-term or accelerated sea level rise (ASLR) together with local predictions of extreme storm waves and surges showed that by 2060, the combination of ASLR and extreme wave surges will have a devastating impact on Negril’s beaches and the coastal infrastructure behind it. This has significant implications for risk reduction and adaptation planning. RiVAMP was intended to be used for Small Island Developing States (SIDS) with similar risks as Jamaica, and holds potential for other island states highly exposed to rising sea levels.
Source: UNEP, 2010
There are various initiatives and resources that combine multi-hazard risk assessment and climate change scenarios, such as the Probabilistic Risk Assessment Initiative (CAPRA), the Pacific Catastrophe Risk Assessment and Financing Initiative (PCRAFI) and the GeoNetwork.