Climate change adaptation and livelihood outcomes under rainfall variability: evidence from smallholder farmers in semi-arid Tanzania

Climate change is increasingly affecting agricultural systems in sub-Saharan Africa, particularly in semi-arid regions where rainfall variability poses significant risks to smallholder livelihoods. This study examines the effectiveness of adaptation strategies in improving livelihood outcomes for smallholder farmers facing rainfall variability in Singida District, Tanzania. The study uses historical rainfall data (1985–2024) and household survey data from 406 farming households. Rainfall trends were analyzed using the Mann–Kendall test and Sen’s slope estimator. The results show high rainfall variability (coefficient of variation = 22.9%) and a statistically insignificant upward trend (Sen’s slope = 1.27 mm/year). Farmers respond by adopting multiple adaptation strategies, with crop diversification (99.5%) and drought-tolerant crops (71.4%) being the most prevalent measures. The results show that rainfall variability affects livelihood outcomes (β = −0.380, p < 0.01). Instrumental variable estimates show a positive and statistically significant effect of adaptation strategies on livelihood outcomes (β = 2.614, p < 0.05). The findings suggest that adaptation strategies can strengthen food security, agricultural productivity, and income stability under rainfall variability. Generally, the results demonstrate that while adaptation plays a critical role in sustaining livelihoods amid climate variability, its benefits are context-dependent. The study provides policy-relevant evidence to inform the design of targeted and integrated interventions that strengthen climate resilience in semi-arid agricultural systems in Africa.