Smallholder Adaptation to Climate Change in the West African Sahel: A Critical Narrative Review of Practices, Evidence and the Limits of Incremental Adjustment

Abstract

Rainfed smallholder agriculture in the West African Sahel operates within one of the most variable rainfall regimes on the planet, and the adaptation of Sahelian farming households has become a substantial field of research spanning agronomy, climatology, economics, geography and development studies. This review examines that literature critically rather than descriptively, asking what can defensibly be concluded about the practices Sahelian smallholders adopt, the conditions under which those practices deliver benefits, and the quality of the evidence supporting current policy enthusiasm. Literature was identified through structured searching of open scholarly databases and indexes, supplemented by citation chaining and searches of authoritative institutional sources, and was appraised for design adequacy, measurement validity, treatment of confounding, external validity and consistency with independent evidence. Six analytical themes are developed: the climatic signal and its agronomic translation; perception and its uncertain link to action; land and water management as the core adaptation repertoire; varietal and crop-calendar adjustment; information, insurance and finance; and diversification, mobility and non-farm response. The synthesis indicates that the strongest evidence concerns the agronomic effects of soil and water conservation, nutrient microdosing and farmer-managed natural regeneration under defined biophysical conditions, and that the weakest evidence concerns whether these practices reduce climate-related risk over time at household scale. Much of the adoption literature relies on single-round cross-sectional surveys, self-reported adaptation and estimators whose identifying assumptions are rarely defended, which limits causal interpretation of reported welfare gains. Recurrent findings that adaptation is concentrated among better-endowed households, and evidence that some responses shift rather than reduce vulnerability, indicate that the field has under-examined distributional outcomes and maladaptation. Priorities include longitudinal and spatially explicit measurement of adaptation, pre-specified evaluation of scaled programmes, and analysis of the conditions under which incremental adjustment ceases to be sufficient.