Recognizing the Interconnected Crises
Over 200 health journals across the world have come together to simultaneously publish this call to action, urging world leaders and health professionals to recognize that climate change and biodiversity loss are not separate challenges, but rather one indivisible crisis that must be tackled together to preserve human health and avoid catastrophe.
This is a dangerous mistake. The world is currently responding to the climate crisis and the nature crisis as if they were distinct issues, when in fact they are deeply interconnected. As the health world has recognized through the development of the concept of planetary health, the natural world is made up of one overall interdependent system. Damage to one subsystem can create feedback that damages another – for example, drought, wildfires, floods and other effects of rising global temperatures destroy plant life, leading to soil erosion and inhibiting carbon storage, which in turn fuels more global warming.
In fact, climate change is set to overtake deforestation and other land-use changes as the primary driver of nature loss. Meanwhile, the remarkable regenerative power of nature, including the ability of deforested land to revert to forest through natural processes and the rapid turnover of marine phytoplankton that act as natural carbon sinks, demonstrates how restoring one subsystem can help another. However, actions intended to benefit one subsystem can also inadvertently harm another, such as planting forests with a single tree species to remove carbon dioxide but compromising the biodiversity fundamental to healthy ecosystems.
The Profound Health Impacts
Human health is profoundly damaged by both the climate crisis and the nature crisis. The indivisible planetary crisis will have major effects on health through the disruption of social and economic systems – shortages of land, shelter, food, and water that exacerbate poverty and lead to mass migration and conflict. Rising temperatures, extreme weather events, air pollution, and the spread of infectious diseases are just some of the major health threats exacerbated by climate change.
As UN Secretary-General António Guterres bluntly stated, “Without nature, we have nothing.” Even if we could limit global warming to 1.5°C above pre-industrial levels, we could still cause catastrophic harm to health by destroying nature. Access to clean water, crucial for human health, has been damaged by pollution leading to a rise in waterborne diseases. Nutritional diversity, underpinned by a variety of foods, has been severely compromised by the loss of genetic diversity in the food system, with about a fifth of the world’s population relying on wild species for food and livelihoods. The decline of wildlife, especially in low- and middle-income countries, poses a major challenge, as fish provide more than half of dietary protein in many African, South Asian and small island nations, but ocean acidification has reduced seafood quality and quantity.
Changes in land use have forced tens of thousands of species into closer contact, increasing the exchange of pathogens and the emergence of new diseases and pandemics. The loss of contact with the natural environment and declining biodiversity have also been linked to increases in noncommunicable, autoimmune, and inflammatory diseases, as well as metabolic, allergic and neuropsychiatric disorders.
For Indigenous communities, the health benefits of caring for and connecting with nature are particularly important. Nature has also been a crucial source of medicines, so reduced diversity constrains the discovery of new treatments. Even the health benefits of access to high-quality green spaces, which filter air pollution, regulate temperatures, and provide opportunities for physical activity, are threatened by the continuing rise in urbanization.
Crucially, the health impacts of climate change and biodiversity loss are experienced unequally, with the most vulnerable communities often bearing the highest burden. This inequality is also arguably fueling these environmental crises, as the drivers of environmental challenges and social/health inequities are intertwined, presenting opportunities for co-benefits in addressing them.
A Global Health Emergency
In December 2022, the biodiversity conference (COP) agreed on the effective conservation and management of at least 30% of the world’s land, coastal areas, and oceans by 2030, with industrialized countries committing to mobilize $30 billion per year to support developing nations. These agreements echo promises made at climate COPs, yet many commitments have not been met, allowing ecosystems to be pushed further to the brink and greatly increasing the risk of abrupt breakdowns in the functioning of nature. If these tipping points were to occur, the impacts on health would be globally catastrophic.
This risk, combined with the severe impacts on health already occurring, means that the World Health Organization should declare the indivisible climate and nature crisis as a global health emergency before or at the Seventy-seventh World Health Assembly in May 2024. The three pre-conditions for WHO to declare a situation as a Public Health Emergency of International Concern are:
- It is serious, sudden, unusual or unexpected.
- It carries implications for public health beyond the affected State’s national border.
- It may require immediate international action.
Climate change and biodiversity loss, while not sudden or unexpected, are certainly serious and unusual, and meet all three criteria for WHO to make this declaration. Tackling this emergency requires harmonizing the separate COP processes for climate and nature, starting with better integration of national climate plans and biodiversity equivalents.
A Call to Action for Health Professionals and Leaders
As the 2020 workshop that brought climate and nature scientists together concluded, critical leverage points include exploring alternative visions of good quality of life, rethinking consumption and waste, shifting values related to the human-nature relationship, reducing inequalities, and promoting education and learning – all of which would benefit health.
Health professionals must be powerful advocates for restoring biodiversity and tackling climate change to preserve human health. Political leaders must recognize both the severe threats to health from the planetary crisis and the benefits that can flow from addressing it. But first, we must all recognize this crisis for what it is: a global health emergency that demands immediate, coordinated action.
Human health is intrinsically linked to the health of our planet. The time has come to treat the climate and nature crises as one indivisible global health emergency, and to mobilize all available resources to confront this existential threat to humanity. The future of our communities, our economies, and our very way of life depends on it.
