Climate Change, Heat Stress, and Agricultural Worker Health in Northern Nigeria: A Longitudinal Climate-Health Integration Study

Climate change is projected to increase ambient temperatures across West Africa by 2 to 4 degrees Celsius by 2050, with profound implications for occupational heat stress among the predominantly outdoor agricultural workforce of Northern Nigeria. This doctoral study integrated climate science and occupational health epidemiology to examine the relationship between increasing temperature trends, occupational heat stress, and worker health outcomes in agricultural communities across Kano, Sokoto, and Kebbi States, North West Nigeria. A longitudinal cohort design followed 600 farm workers over four agricultural seasons from 2022 to 2024, combined with downscaled regional climate modeling for projected temperature scenarios. Occupational heat stress was measured using WBGT index, and health outcomes included heat-related illness incidence, cardiorespiratory physiological strain, work capacity, and agricultural productivity measures. Results demonstrated a 34.2 percent increase in days exceeding the 32 degrees Celsius WBGT threshold for heavy work over the study period, corresponding with a 28.6 percent increase in heat illness incidence and a 19.3 percent reduction in work capacity. Climate projection modeling indicates a 2.4-fold increase in heat stress burden by 2040 under RCP 4.5 scenarios. The study develops an original Occupational Heat-Agricultural Productivity model applicable to Sahelian farming contexts. Recommendations include climate-adaptive work scheduling, irrigation expansion for microclimate cooling, and integration of heat stress adaptation into Nigeria's National Climate Change Action Plan. Keywords: climate change, heat stress, agricultural workers, longitudinal study, Northern Nigeria.