Climate change and environmental degradation represent the defining public health challenges of the twenty-first century, exerting profound direct and indirect impacts on global well-being. Their effects are far-reaching from increased incidence of vector-borne diseases and heat-related illnesses to disruptions in food and water systems, mental health burdens, widening health inequities, socioeconomic collapse, and conflict. This review integrates multidisciplinary evidence across climatology, ecology, medicine, and digital health to illuminate the complex linkages between environmental degradation and human health outcomes. Rising temperatures, altered precipitation patterns, oceanic disruption, and biodiversity loss are amplifying vector-borne diseases, food insecurity, and heat-related morbidity. These systemic stresses disproportionately affect vulnerable populations, accelerating inequities and threatening societal stability. Building on recent frameworks, this paper advances a holistic Climate–Health Nexus model that emphasizes adaptive resilience through surveillance, early warning systems, and decision intelligence. Professor Hugh Montgomery’s analogy of climate change as a critically ill patient underscores the urgency for coordinated, evidence-based intervention. Integrating insights from digital health platforms such as MyJEEVA, we outline how community-level engagement, real-time data, and AI-enabled decision support can enhance climate preparedness and health system responsiveness. The synthesis concludes with actionable pathways linking mitigation, adaptation, and governance to safeguard planetary and human health.