Vulnerability of small-scale farming livelihoods under climate variability in a globally important archipelago of the Global South

In recent decades, the pace of change in social-ecological systems has accelerated. The adverse effects of climate variability and extreme events put increasing pressure on rural small-scale farmers' households whose livelihoods depend on nature. However, socioeconomic, political, and institutional changes also affect this group, responsible for producing at least a third of the world's food. This study assessed the influence of climate variability on the spatial distribution of the social-ecological vulnerability of small farmers' livelihoods within a Globally Important Agricultural Heritage System (GIAHS) in southern South America. Data were collected through a questionnaire-based survey of 100 small-scale farmers' households, selected via stratified random sampling. Climate variability and extreme event data spanning 30 years were included, with spatial and temporal resolutions of 1 × 1 km and one year, respectively. Through an indicator-based approach, the study identified 17 vulnerability indicators across Exposure, Sensitivity, and Adaptive Capacity components. The Livelihood Vulnerability Index (LVI) for small-scale farming in the Chiloé Archipelago was calculated at the household level, following the IPCC vulnerability assessment framework and the Sustainable Livelihoods perspective. The findings reveal that LVI values for small-scale farmers ranged from 0.28 (least vulnerable) to 0.54 (most vulnerable). Principal Component Analysis indicated that agricultural extension support, supplementary income, social relations, and ownership of agricultural equipment enhance local adaptive capacity. Spatial autocorrelation analysis revealed clustering in exposure, sensitivity, adaptive capacity, and vulnerability patterns. The finding suggests that extension interventions should strengthen vulnerable households' adaptive capacity by supporting rural livelihood diversification.