Methods and Tools Applied for Climate Change Vulnerability and Adaptation Assessment in Cambodia’s Tonle Sap Basin
Cambodia is highly susceptible to natural disasters due to the frequency and intensity of extreme climatic events, primarily floods, droughts and windstorms, but also in particular to increased climate variability.These disasters and climate-related hazardshave exacted huge socioeconomic costs on the country’s economy and people’s livelihoods, especially in the last decade. It isimportant, therefore, to understand not only the level of impactbut also the vulnerability and the capacity of people to adapt to these hazards. This emphasises the needfor vulnerability and adaptation assessmentsthat are tailored to site-specific local scale.
This paper reviews existing methods and tools used for understanding the impacts of climate change, the vulnerability and the adaptive capacity of local people, with a particular focus on water use and governance in three project target areas in the Tonle Sap Basin, under the project “Climate Change and Water Governance in Cambodia”. The objectives of this review are twofold: to understand how different organisations have approached the evaluation of vulnerability and adaptive capacity in relation to climate change and water governance; and toanalyse the strengths and gaps in existing tools and methods based on how they address vulnerability and adaptation as a function of exposure, sensitivity and adaptive capacity.
The tools and methods that have been applied by various organisations in different institutional settings and at different geographical scales and locationscan be broadly grouped under three categories: climate, hydrologicaland socioeconomic modelling and downscaling; participatory approaches that engage local communities; and decision support tools to evaluate alternative adaptation strategies.
To detect trends and understand the implications of climate change at the local level, the regional climate modelling system Providing REgional Climates for Impacts Studies (PRECIS) can be used to downscale the outputs of general circulation models (GCMs) from the national scale (Cambodia) to catchment (Tonle Sap) scale.Hydrological models, the Soil and Water Assessment Tool (SWAT) and Integrated Water Quantity and Quality Model (IQQM) have been applied at the catchment level to generate new understandingabout river basin and human controls on the spatial and temporal distribution of water flow and to deepen understanding of supply-demand relationships. Also, ISIS—a software package that can simulate water flow, hydrology, water quality changes and sediment transport in rivers, floodplains, lakes, canals and coastal areas—has been used as a flood forecasting tool in the Tonle Sap Basin.
Participatory tools including climate vulnerability and capacity analysis (CVCA), communitybased adaptation toolkits and participatory capacity and vulnerability assessment (PCVA) have been used to assess the impacts of climate variability and change on local livelihoods, especiallythose of vulnerable groups. This approach tries to understand how people directly experience the effects of climate change.
Cost benefit analysis (CBA) and multi-criteria analysis (MCA) are popularly used as decision support tools for selecting and prioritising interventions and/or projects as well as relevant policy areas relatedto climate change.
The review concludes that testing the extent of climate change vulnerability and adaptive capacity requires an integrated approach combining comprehensive vulnerability and adaptation assessment frameworks. Whether these vulnerability assessment frameworks should be applied simultaneously or one at a time dependson the specific context,data availabilityand resource requirements.
Indicators and indices that measure climate change exposure, sensitivity and adaptive capacity could be used to produce maps showing the spatial distribution of these three components of vulnerability. In the Tonle Sap, the indicators should be used for monitoring the extent of adaptation, mitigation and vulnerability at the community and local levels.
The selection, application and cost-effective use of appropriate databases,tools and methods, and the conduct ofcommunity and catchment-level vulnerability and adaptation assessments will eventually lead to recommendations for improved and locally-appropriate site- and contextspecific vulnerability adaptation measures in the Tonle Sap Basin catchments.