Global venomous snake redistribution and snakebite risk under climate change

Climate change is reshaping the global distribution of venomous snakes, with important implications for public health. Snakebite envenoming is estimated to cause approximately 63,400 deaths annually, mostly in tropical and developing countries. However, few studies have comprehensively assessed the future global patterns of envenomation risk, particularly across venom types with differing clinical and ecological characteristics. In this study, we modeled the current and future distributions of 193 medically important venomous snake species (neurotoxic and hemotoxic) under 4 climate change scenarios through 2100. We assessed 3 indices to quantify snakebite risks: the Venom Richness Index (VRI) for species-specific venom diversity, the Snakebite Range Expansion Index (SREI) to capture range expansion or contraction, and the Venom Overlap Index (VOI) for geographic co-occurrence of venom types. We found that snakebite risk is projected to increase in temperate and cold regions under high-emissions scenarios, with VRI and SREI increasing in areas such as North America, Europe, and East Asia. In contrast, VRI and SREI are projected to decline across parts of tropical Africa, India, and southern China. VRI transitions are projected to expand in northern Mexico, Brazil, Spain, southwestern China, and southern Australia, increasing the potential for diagnostic uncertainty and treatment complexity. VOI is expected to rise in highly populated but poorly urbanized regions, highlighting the vulnerability of developing countries with limited infrastructure. These spatial and venom-specific shifts underscore the need for regionally tailored antivenom strategies, improved diagnostics, and high-resolution risk forecasting to mitigate the future burden of snakebite under global change.