17:15 〜 19:15
[HCG24-P06] Assessing climate variability impacts on water availability and economic resilience in the Limpopo River Basin, Southern Africa
キーワード：Climate models, Extreme precipitation, River basin management, Hydro-economic models, Water policy
Extreme rainfall events impact hydrological and socioeconomic systems in southern Africa, particularly in transboundary river basins like the Limpopo. Spanning ~414,800 km² across South Africa (45%), Botswana (19%), Mozambique (21%), and Zimbabwe (15%), the Limpopo River Basin (LRB) faces persistent challenges in balancing water supply and quality, mitigating flood and drought risks, and sustaining water-dependent economies under increasing climate variability (Heyns et al., 2008).
Regional climate models (e.g., CORDEX, CORE) outperform global models (CMIP5, CMIP6) in simulating rainfall extremes in the region (Samuel et al., 2023), though wet biases in threshold-based indices (e.g., R10mm, R20mm) reduce reliability. Percentile-based indices (e.g., the 95th and 99th percentiles of daily rainfall) may be more robust given the large variation in mean annual rainfall (160–1103 mm) (Mosase & Ahiablame, 2018). Additionally, large-scale climate drivers, such as sea surface temperature (SST) variability, influence extreme rainfall events in the region, affecting seasonal cycles, droughts, and flood risks (Hoell et al., 2017). These dynamics highlight the need for integrated climate-hydrology-economic assessments to improve risk evaluation and decision-making.
This study assesses the projected impacts of changes in rainfall, temperature, and moisture on water resources, agriculture, and eco-tourism in the LRB under different scenarios. We establish a baseline by analyzing historical climate trends and rainfall drivers, then integrate projections into a model linking climate, hydrological, and economic systems to assess water allocation and sectoral trade-offs. The model uses a basin-scale water balance approach, incorporating climate-driven streamflow projections (e.g., up to 20% reductions under severe droughts) (Watson et al., 2022) and sectoral water demand functions. Agricultural water demand is modeled using crop water requirements and yield response functions, with economic losses estimated via price elasticities (-0.2 to -0.8) and productivity shifts derived from Cobb-Douglas production functions (Bekchanov et al., 2015). For instance, a 25% irrigation water reduction could lower total crop output by 8% (Medellín-Azuara et al., 2012). Eco-tourism revenues are assessed using visitor demand elasticities (Zhou et al., 2024).
Findings have direct implications for designing effective adaptation strategies to enhance climate resilience, support sustainable water management, balance sectoral demands, and safeguard socio-economic stability across the basin.
References
Bekchanov, M. et al., 2015. Review of hydro-economic models to address river basin management problems: Structure, applications and research gaps. IWMI.
Heyns, P.S. et al., 2008. Transboundary water resource management in Southern Africa: meeting the challenge of joint planning and management in the Orange River basin. Int. J. Water Resour. Dev., 24(3), pp.371-383.
Hoell, A. et al., 2017. Modulation of the southern Africa precipitation response to the El Niño Southern Oscillation by the subtropical Indian Ocean dipole. Clim. Dyn., 48, 2529-2540.
Medellín-Azuara, J. et al., 2012. Analysis of effects of reduced supply of water on agricultural production and irrigation water use in Southern California. Univ. of California Agricultural Issues Center, Davis, California.
Mosase, E., & Ahiablame, L., 2018. Rainfall and temperature in the Limpopo river basin, Southern Africa: Means, variations, and trends from 1979 to 2013. Water, 10(4), 364.
Samuel, S. et al., 2023. Comparison of multimodel ensembles of global and regional climate models projections for extreme precipitation over four major river basins in southern Africa—Assessment of the historical simulations. Clim. Change., 176(5), 57.
Watson, A. et al., 2022. Using soil-moisture drought indices to evaluate key indicators of agricultural drought in semi-arid Mediterranean Southern Africa. Sci. Total Environ., 812, 152464.
Zhou, W. et al., 2024. Meta-analysis of the climate change-tourism demand relationship. J. Sustain. Tour., 1-22.
Regional climate models (e.g., CORDEX, CORE) outperform global models (CMIP5, CMIP6) in simulating rainfall extremes in the region (Samuel et al., 2023), though wet biases in threshold-based indices (e.g., R10mm, R20mm) reduce reliability. Percentile-based indices (e.g., the 95th and 99th percentiles of daily rainfall) may be more robust given the large variation in mean annual rainfall (160–1103 mm) (Mosase & Ahiablame, 2018). Additionally, large-scale climate drivers, such as sea surface temperature (SST) variability, influence extreme rainfall events in the region, affecting seasonal cycles, droughts, and flood risks (Hoell et al., 2017). These dynamics highlight the need for integrated climate-hydrology-economic assessments to improve risk evaluation and decision-making.
This study assesses the projected impacts of changes in rainfall, temperature, and moisture on water resources, agriculture, and eco-tourism in the LRB under different scenarios. We establish a baseline by analyzing historical climate trends and rainfall drivers, then integrate projections into a model linking climate, hydrological, and economic systems to assess water allocation and sectoral trade-offs. The model uses a basin-scale water balance approach, incorporating climate-driven streamflow projections (e.g., up to 20% reductions under severe droughts) (Watson et al., 2022) and sectoral water demand functions. Agricultural water demand is modeled using crop water requirements and yield response functions, with economic losses estimated via price elasticities (-0.2 to -0.8) and productivity shifts derived from Cobb-Douglas production functions (Bekchanov et al., 2015). For instance, a 25% irrigation water reduction could lower total crop output by 8% (Medellín-Azuara et al., 2012). Eco-tourism revenues are assessed using visitor demand elasticities (Zhou et al., 2024).
Findings have direct implications for designing effective adaptation strategies to enhance climate resilience, support sustainable water management, balance sectoral demands, and safeguard socio-economic stability across the basin.
References
Bekchanov, M. et al., 2015. Review of hydro-economic models to address river basin management problems: Structure, applications and research gaps. IWMI.
Heyns, P.S. et al., 2008. Transboundary water resource management in Southern Africa: meeting the challenge of joint planning and management in the Orange River basin. Int. J. Water Resour. Dev., 24(3), pp.371-383.
Hoell, A. et al., 2017. Modulation of the southern Africa precipitation response to the El Niño Southern Oscillation by the subtropical Indian Ocean dipole. Clim. Dyn., 48, 2529-2540.
Medellín-Azuara, J. et al., 2012. Analysis of effects of reduced supply of water on agricultural production and irrigation water use in Southern California. Univ. of California Agricultural Issues Center, Davis, California.
Mosase, E., & Ahiablame, L., 2018. Rainfall and temperature in the Limpopo river basin, Southern Africa: Means, variations, and trends from 1979 to 2013. Water, 10(4), 364.
Samuel, S. et al., 2023. Comparison of multimodel ensembles of global and regional climate models projections for extreme precipitation over four major river basins in southern Africa—Assessment of the historical simulations. Clim. Change., 176(5), 57.
Watson, A. et al., 2022. Using soil-moisture drought indices to evaluate key indicators of agricultural drought in semi-arid Mediterranean Southern Africa. Sci. Total Environ., 812, 152464.
Zhou, W. et al., 2024. Meta-analysis of the climate change-tourism demand relationship. J. Sustain. Tour., 1-22.