Time to Treat the Climate and Nature Crisis as One Indivisible Global Health Emergency

The article argues that climate change and biodiversity loss constitute a single, indivisible planetary crisis with profound implications for global health. It critiques current global governance for addressing climate and nature as separate issues (e.g., COP28 for climate and COP16 for biodiversity) and warns that this separation is a dangerous mistake. Citing a 2020 IPBES-IPCC workshop, the authors emphasize that integrated approaches are essential to avoid maladaptation and to maximize health and environmental benefits. The purpose is to call on the United Nations, political leaders, and health professionals to recognize and treat the combined climate–nature crisis as a global health emergency requiring urgent, coordinated action.

The piece synthesizes cross-disciplinary evidence from planetary health, climate science, and biodiversity research. It highlights ecological interdependence and feedback loops where damage in one subsystem (e.g., climate-driven droughts, wildfires, and floods) degrades biodiversity and carbon storage, amplifying warming. It notes that climate change is on course to surpass land-use change as the primary driver of biodiversity loss. The authors describe nature’s regenerative capacity (e.g., natural forest regeneration; rapid turnover of marine phytoplankton biomass) and the vital role of Indigenous land and sea stewardship in conservation and restoration. They also discuss the potential for synergistic gains (e.g., soil restoration enhancing carbon sequestration) and trade-offs (e.g., monoculture tree planting sequestering carbon but harming biodiversity). The review integrates public health literature linking environmental degradation with water quality declines, food and nutrition insecurity, infectious disease emergence from altered land use, and associations between reduced biodiversity/nature contact and noncommunicable and neuropsychiatric conditions. It also cites evidence for health benefits of urban green spaces and the uneven distribution of environmental burdens, underscoring the intersection of environmental crises with social inequities.

- Climate change and biodiversity loss are interdependent, mutually reinforcing crises that must be addressed together to protect health and prevent catastrophic outcomes. - Health harms are both direct (e.g., heat, extreme weather, air pollution, infectious disease spread) and indirect via disruption of land, shelter, food, and water systems, leading to poverty, migration, and conflict. - Water pollution is degrading drinking water quality and raising water-borne diseases; terrestrial contamination impacts distant marine ecosystems via runoff. - Global nutrition depends on food diversity; there is marked loss of genetic diversity in food systems. About one-fifth of people rely on wild species for food and livelihoods, and many countries (in Africa, South Asia, and small island states) obtain more than half of dietary protein from fish. Ocean acidification is reducing seafood quality and quantity. - Land-use change is increasing cross-species contact, elevating pathogen exchange and pandemic risk. Reduced biodiversity and diminished human-nature contact are linked to increases in noncommunicable, autoimmune, inflammatory, metabolic, allergic, and neuropsychiatric disorders. - Access to quality green spaces improves physical and mental health, reducing air pollution exposure, cooling local climates, encouraging activity, and fostering social connection; these benefits are threatened by accelerating urbanization. - Environmental and health impacts are distributed unequally within and between countries; shared structural drivers mean co-benefits are possible when addressing environmental challenges and inequities. - Despite the 2022 biodiversity COP commitment to conserve/manage at least 30% of land, coastal areas, and oceans by 2030 and to mobilize $30 billion per year for developing nations, many COP commitments remain unmet, pushing ecosystems toward tipping points with potentially globally catastrophic health impacts. - Nature’s regenerative capacities offer solutions (e.g., natural forest regeneration; marine phytoplankton turnover of ~1 billion tonnes of photosynthesizing biomass every eight days), but poorly designed interventions (e.g., single-species plantations) can harm biodiversity.

Framing climate change and biodiversity loss as a single planetary health crisis clarifies that siloed responses risk maladaptation and missed co-benefits. The authors argue that the scale and nature of current and projected health harms meet the World Health Organization’s criteria for a Public Health Emergency of International Concern: the crisis is serious and unusual, crosses borders, and requires immediate international action. They call for WHO to declare this emergency by or before the 77th World Health Assembly (May 2024). To operationalize an integrated response, they recommend harmonizing the climate and biodiversity COP processes and aligning national climate plans with biodiversity strategies. They emphasize leverage points including new visions of good quality of life, reducing consumption and waste, shifting values about human–nature relationships, addressing inequalities, and strengthening education—measures that also improve health. Health professionals are urged to advocate for restoration of biodiversity and climate action, highlighting the substantial health co-benefits of integrated environmental policy.

The article’s central contribution is a unified framing of climate change and biodiversity loss as one indivisible global health emergency. It issues a call to action for WHO to declare this emergency, for international processes (particularly the COPs) to be harmonized, and for national plans to integrate climate and biodiversity objectives. It underscores the health co-benefits of ecosystem restoration, sustainable resource use, and equity-focused policies. Future directions include developing and implementing integrated policy frameworks, strengthening interdisciplinary research bridging climate, biodiversity, and health, evaluating co-benefit interventions that avoid trade-offs, and supporting Indigenous and community-led stewardship as part of global health strategies.