ADOPT, a socio-hydrologic, agent-based drought adaptation model to evaluate drought risk reduction strategies for smallholder farmers in semi-arid Kenya

Abstract:

To account for dynamic adaptive behaviour in risk models, we developed a multidisciplinary agricultural drought risk model, ADOPT, that simulates the bounded-rational agricultural water management decisions of smallholder farmers in the Kenyan Drylands (Wens, 2020). The model combines a socio-hydrologic and agent-based approach and fits within the traditional disaster risk framework. Coupled with the FAO crop water model AquacropOS (Foster et al. 2017) and parameterised with a rich empirical dataset including information from stakeholder interviews, a water managers survey and extensive household survey and choice experiment among farmers in the Kenya drylands (Wens, 2018; Wens, 2019), the model estimates yield losses, food insecurity and emergency aid needed as a result of droughts.

Endogenizing the feedbacks between agricultural water management decisions and seasonal weather conditions, and incorporating perceptions, adoption constraints and social interactions, we show that the reality of complex human adaptation decisions can best be described assuming bounded rational adaptive behaviour; and that an agent-based approach and the choice of adaptation theory matter when quantifying historic risk. Furthermore, we explore farmers’ reactions to changing drought occurrence under RCP2.6 - RCP8.5 and under popular governmental policies regarding resilience building. Supported by econometric analyses, the model allows comparing the effect of climate change and pro- and reactive top-down decisions on the household- and community drought risk.

We demonstrate that progressed extension services, improved early warning systems, ex-ante cash transfers and a reduced credit rate, increases - on average and in descending order of magnitude – farmers’ intention to adopt new measures. A multitude of reactions towards said policies appear possible, with climate change, education, cropland size and household expenses as well as interactions between the policies largely defining the magnitude of their efficiency. The model highlights the conditions required to break the economic poverty - environmental fragility vicious circle and incentivise farmers towards climate-smart agriculture, thus ensuring reduced drought risk, related losses and aid needs.