Feeding the Future: Agroecological Pathways to Climate Adaptation and Food Security

Tropical and subtropical regions account for a large and expanding share of global milk output, yet the scientific literature that underpins dairy management remains dominated by evidence generated in temperate systems. This review critically examines the intersection of thermal stress, environmental sustainability and climate adaptation in tropical dairy production, and asks whether the prevailing evidence base is adequate to guide practice in the settings where warming is likely to be felt most acutely. Literature was identified through structured searching of multidisciplinary and biomedical scholarly indexes, supplemented by citation tracking, and was appraised for design quality, contextual relevance and consistency rather than aggregated quantitatively. Four problems recur across the reviewed evidence. Exposure is characterised almost universally by the temperature-humidity index, an aggregate measure whose thresholds were derived largely from high-yielding temperate herds and which performs inconsistently when applied to crossbred and indigenous genotypes under humid tropical conditions. The productive, reproductive and health consequences of chronic moderate thermal load are quantified far less reliably than the acute responses characterised in controlled facilities. Adaptation options are usually evaluated in isolation, so the interactions among genetic improvement, feeding, cooling infrastructure and herd management remain largely unquantified. Environmental assessments of tropical milk report wide between-farm variation in emissions intensity that is attributed principally to animal productivity, yet these analyses seldom incorporate the effect of heat load on performance, which recent experimental work indicates may raise methane yield and intensity directly. The evidence supports a cautious conclusion that improved animal productivity lowers emissions per unit of milk in most tropical settings, although the magnitude and durability of that benefit under progressive warming remain uncertain. Priorities include locally calibrated thermal metrics, longitudinal on-farm study of chronic exposure, factorial evaluation of combined adaptation packages, and environmental assessment that explicitly represents climate feedbacks on animal performance.