2025’s Global Health Polycrisis: Climate, Contagion and the Limits of our Defences

This article explores how 2025 marked a defining year for global public health, shaped by a polycrisis of resurgent infectious diseases, climate-driven emergencies, antimicrobial resistance, and an escalating mental health burden. It details the re-emergence of diseases like measles and mpox, record-breaking dengue outbreaks, and rising drug-resistant infections, alongside the growing toll of extreme heat, air pollution, and flooding on both physical and mental health. The piece highlights the operationalisation of the “One Health” framework and the shift toward integrated surveillance, AI-enabled diagnostics, and pragmatic medtech adoption. While 2025 saw major technological gains, the year underscored the fragility of global health defences and the urgency of sustained investment in climate-resilient, accessible, and systems-based health care.