A Dynamic Assessment of Water Scarcity Risk and Climate Change Adaptation in the Lower Brahmaputra River Basin

For assessing vulnerability and risk of water resources system and defining climate change adaptation policies and measures, the integrated contribution of several disciplines is required, enabling a comprehensive, but also complex, dynamic description of present state and future trends. But, the notions of vulnerability and risk and the approaches for their assessment, have found different and often contrasting solutions by various schools of thought over recent times. For example, the traditional conceptualization of vulnerability and risk by the disaster risk reduction (DRR) community is different from that of the climate change adaptation (CCA) community. But there is a need for achieving greater synergy between the two communities to advance sustainable development. Recently the IPCC has released a special report on ‘Managing the risks of extreme events and disasters to advance climate change adaptation’ (IPCC-SREX Report). With the publication of the IPCC-SREX, a substantial move from the CCA community towards the concepts and definitions consolidated in the DRR could be observed, in which vulnerability and risk are conceptualized in a way that can be used to consider both climate change adaptation and disaster risk management. In this study we provide an operational system analysis approach and a simulation tool for water scarcity risk assessment that has been developed within the broad context of climate change adaptation and disaster risk management with an aim to support decision making processes. The methodology has been applied in the Lower Brahmaputra River Basin, a region where hydrological impact of climate change is expected to be strong. In the assessment of risk, indicators selected based on the previously developed framework by Gain et al (2012) and Giupponi et al. (2012) which were further reframed consistent with the recent release of the IPCC-SREX Report– are used to describe past and future trends of model variables, and their trajectories are used to explore possible trends of risk and adaptation needs. As the notion of risk is the result of combined effect of different social and ecological variables, this can not be objectively measured by using a welldefined static or dynamic model. Instead, a subjective way for its estimate is accomplished through a non-additive aggregation operator to construct concise indexes with a weighting procedure reflecting stakeholders' preferences. The results of this study are intended to be used for contributing to planned adaptation of water resources systems, in Bangladesh and other developing countries.