Climate-Driven Environmental Change and Zoonotic Spillover Risk: Implications for One Health Governance

Introduction:
Climate change functions as a pervasive ecological driver reshaping the dynamics of infectious disease emergence. Rising temperatures, altered precipitation patterns, and extreme weather events increasingly affect vector ecology, wildlife migration, and human land use, intensifying interactions at the human–animal–environment interface. These processes collectively elevate the likelihood of zoonotic spillover events. Recognising climate change as a cross-sectoral threat highlights the urgency of strengthening One Health governance frameworks to integrate environmental, veterinary, and public health perspectives within a unified risk management system.

Methods:
A structured narrative review was conducted to examine evidence linking climate-driven environmental change to zoonotic spillover risk. The literature published between 2015 and 2026 was systematically identified through PubMed and Web of Science databases. Eligible studies addressed associations between climatic or ecological changes—such as temperature rise, extreme weather, land-use modification, or biodiversity loss—and zoonotic disease emergence or transmission dynamics. Data were synthesised thematically to elucidate recurrent ecological mechanisms and governance implications; no formal risk-of-bias scoring was applied due to the review’s integrative scope.

Results:
The synthesis identified three primary environmental drivers of spillover: temperature-driven vector expansion (notably Aedes albopictus related to dengue and West Nile virus), extreme weather events triggering vector proliferation or waterborne outbreaks (as in Rift Valley fever following heavy rainfall), and anthropogenic land-use alterations contributing to biodiversity disruption and viral spillover (e.g., Ebola virus disease). Mechanistic patterns included altered vector suitability, wildlife host redistribution, and intensified human–animal contact. Governance analysis revealed fragmented surveillance systems, inadequate integration of climate and health data, and reliance on reactive rather than anticipatory response frameworks.

Conclusions:
Climate change amplifies zoonotic spillover risk by restructuring ecological and epidemiological interactions. Effective prevention necessitates integrated, climate-informed One Health governance that unites environmental, veterinary, and human health sectors. Strengthened transdisciplinary surveillance and predictive modelling are critical for anticipatory risk management in an era of accelerating climate variability.