A global heavy metal risk vulnerability index: Linking agricultural intensification, climate change, and adaptive capacity

Heavy metal contamination is an increasingly serious threat to food safety, environmental sustainability, and human health worldwide. This study proposes a novel Heavy Metal Risk Vulnerability Index (HMRVI) for 12 selected countries over the period 2000–2023, which is constructed through the combination of various anthropogenic indicators including fertilizer consumption, pesticide use, industrial value added, and CO 2 emissions, based on the entropy weight method. Fixed-effects and panel quantile regression models were used to investigate the influence of climate (temperature anomaly, precipitation variability), socioeconomic development (GDP per capita, urbanization), adaptive capacity (ND-GAIN), and ecological capacity (biocapacity per capita) on vulnerability. The results show significant spatial and temporal heterogeneity in heavy metal vulnerability across the selected countries, with China and Brazil recording the highest HMRVI values in 2023, while Pakistan and Nigeria recorded comparatively lower values. Climate variability showed heterogeneous associations across vulnerability levels, while adaptive and ecological capacities were mainly associated with reduced vulnerability in lower-vulnerability contexts. The robustness analyses verify the validity of estimated relationships under alternative model specifications such as panel-corrected standard errors and the exclusion of ND-GAIN. The study provides guidelines for evidence-based policies to reduce heavy metal-related vulnerability and support safer food systems, ensuring food security, and supporting sustainable agricultural development in the face of climate change.