Food Security in the Face of Climate Change: Adaptive Capacity of Small-Scale Social-Ecological Systems To Environmental Variability

Improving the adaptive capacity of small-scale irrigation systems to the impacts of climate change is crucial for food security in Asia. This study analyzes the capacity of small-scale irrigation systems dependent on the Asian monsoon to adapt to variability in river discharge caused by climate change. Our study is motivated by the Pumpa irrigation system, a small-scale irrigation system located in Nepal that is a model for this type of system. Based on ethnographic data, we developed an agent-based model in which we simulated the decisions farmers make about the irrigation strategy to use according to available water flow. Given the uncertainty associated with how climate change may affect the Asian monsoon, we simulated the performance of the system under different projections of climate change in the region (increase and decrease in rainfall, reduction and expansion of the monsoon season, and changes in the timing of the onset of the monsoon). Accordingly to our simulations, farmers will need to adapt to rainfall intensification and a late onset in the monsoon season. The demands for collective action among farmers (e.g. infrastructure repair, meetings, decisions, etc.) might increase considerably due to climate change. Although our model suggests that investment in new infrastructure might increase the performance of the system under some climate change scenarios, the high inequality among farmers when water availability is reduced can hinder the efficiency of these measures due to a reduction of farmers’ willingness to cooperate. Our modeling effort helps to improve our understanding of the most sensitive climate change scenarios for small-scale irrigation farming and helps to frame a discussion of some possible solutions and fundamental trade-offs in the process of adaptation. This understanding is crucial to help small-scale irrigation systems in the adaptation process to climate change for food and water security in Asia.