Over 200 health journals call on the United Nations, political leaders and health
professionals to recognize that climate change and biodiversity loss are one indivisible
crisis and must be tackled together to preserve health and avoid catastrophe. This
overall environmental crisis is now so severe as to be a global health emergency.
The world is currently responding to the climate crisis and the nature crisis as if
they were separate challenges. This is a dangerous mistake. The 28th Conference of
the Parties (COP) on climate change is about to be held in Dubai, while the 16th COP
on biodiversity is due to be held in Turkey in 2024. The research communities that
provide the evidence for the two COPs are unfortunately largely separate, but they
were brought together for a workshop in 2020 when they concluded that: ‘Only by considering
climate and biodiversity as parts of the same complex problem … can solutions be developed
that avoid maladaptation and maximize the beneficial outcomes’(Otto-Portner et al.,
2021).
As the health world has recognized with 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 the other effects of rising global temperatures destroy plant life and
lead to soil erosion and so inhibit carbon storage, which means more global warming
(Ripple et al., 2023). Climate change is set to overtake deforestation and other land-use
change as the primary driver of nature loss (European Academies Science Advisory Council,
2021).
Nature has a remarkable power to restore. For example, deforested land can revert
to forest through natural regeneration, and marine phytoplankton, which act as natural
carbon stores, turn over one billion tonnes of photosynthesizing biomass every 8 days
(Falkowski, 2012). Indigenous land and sea management has a particularly important
role to play in regeneration and continuing care (Dawson et al., 2021).
Restoring one subsystem can help another—for example, replenishing soil could help
remove greenhouse gases from the atmosphere on a vast scale (Bossio et al., 2020).
But actions that may benefit one subsystem can harm another—for example, planting
forests with one type of tree can remove carbon dioxide from the air but can damage
the biodiversity that is fundamental to healthy ecosystems (Levia et al., 2020).
The impacts on health
Human health is damaged directly by both the climate crisis, as the journals have
described in previous editorials (Atwoli et al., 2021; 2022), and by the nature crisis
(WHO, UNEP, Convention on Biological Diversity, 2015). This indivisible planetary
crisis will have major effects on health as a result of the disruption of social and
economic systems—shortages of land, shelter, food and water, exacerbating poverty,
which in turn will lead to mass migration and conflict. Rising temperatures, extreme
weather events, air pollution and the spread of infectious diseases are some of the
major health threats exacerbated by climate change (Magnano San Lio et al., 2023).
‘Without nature, we have nothing,’ was UN Secretary-General António Guterres’s blunt
summary at the biodiversity COP in Montreal last year (Jelskov, 2022). Even if we
could keep global warming below an increase of 1.5°C over pre-industrial levels, we
could still cause catastrophic harm to health by destroying nature.
Access to clean water is fundamental to human health, and yet pollution has damaged
water quality, causing a rise in water-borne diseases (World Health Organization,
2022). Contamination of water on land can also have far-reaching effects on distant
ecosystems when that water runs off into the ocean (Comeros-Raynal et al., 2021).
Good nutrition is underpinned by diversity in the variety of foods, but there has
been a striking loss of genetic diversity in the food system. Globally, about a fifth
of people rely on wild species for food and their livelihoods (IPBES, 2022). Declines
in wildlife are a major challenge for these populations, particularly in low- and
middle-income countries. Fish provide more than half of dietary protein in many African,
South Asian and small island nations, but ocean acidification has reduced the quality
and quantity of seafood (Falkenberg et al., 2020).
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
(Dunne, 2022). People losing contact with the natural environment and the declining
loss in biodiversity have both been linked to increases in noncommunicable, autoimmune
and inflammatory diseases and metabolic, allergic and neuropsychiatric disorders (WHO,
UNEP, Convention on Biological Diversity, 2015; Altveş et al., 2020). For Indigenous
people, caring for and connecting with nature is especially important for their health
(Schultz and Cairney, 2017). Nature has also been an important source of medicines,
and thus, reduced diversity also constrains the discovery of new medicines.
Communities are healthier if they have access to high-quality green spaces that help
filter air pollution, reduce air and ground temperatures and provide opportunities
for physical activity (Macguire et al., 2022). Connection with nature reduces stress,
loneliness and depression while promoting social interaction (Wong et al., 2018).
These benefits are threatened by the continuing rise in urbanization (Simkin et al.,
2022).
Finally, the health impacts of climate change and biodiversity loss will be experienced
unequally between and within countries, with the most vulnerable communities often
bearing the highest burden (WHO, UNEP, Convention on Biological Diversity, 2015).
Linked to this, inequality is also arguably fuelling these environmental crises. Environmental
challenges and social/health inequities are challenges that share drivers, and there
are potential co-benefits of addressing them (WHO, UNEP, Convention on Biological
Diversity, 2015).
A global health emergency
In December 2022, the biodiversity COP agreed on the effective conservation and management
of at least 30% of the world’s land, coastal areas and oceans by 2030 (Secretariat
of the Convention on Biological Diversity, 2022). Industrialized countries agreed
to mobilize $30 billion per year to support developing nations to do so (Secretariat
of the Convention on Biological Diversity, 2022). These agreements echo promises made
at climate COPs.
Yet many commitments made at COPs have not been met. This has allowed ecosystems to
be pushed further to the brink, greatly increasing the risk of arriving at ‘tipping
points’, abrupt breakdowns in the functioning of nature (Armstrong Mckay et al., 2022;
Ripple et al., 2023). If these events 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 WHO should declare the indivisible climate and nature crisis as a global health
emergency. The three pre-conditions for WHO to declare a situation to be a Public
Health Emergency of International Concern (WHO guidance for the use of Annex 2 of
the International Health Regulations (2005)) are that it (1) is serious, sudden, unusual
or unexpected, (2) carries implications for public health beyond the affected state’s
national border and (3) may require immediate international action. Climate change
would appear to fulfil all of those conditions. While the accelerating climate change
and loss of biodiversity are not sudden or unexpected, they are certainly serious
and unusual. Hence, we call for WHO to make this declaration before or at the 77th
World Health Assembly in May 2024.
Tackling this emergency requires the COP processes to be harmonized. As a first step,
the respective conventions must push for better integration of national climate plans
with biodiversity equivalents (European Academies Science Advisory Council, 2021).
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’ (Otto-Portner
et al., 2021). All of these would benefit health.
Health professionals must be powerful advocates for both restoring biodiversity and
tackling climate change for the good of health. Political leaders must recognize both
the severe threats to health from the planetary crisis as well as the benefits that
can flow to health from tackling the crisis (Australian Government Department of Health
and Aged Care, 2023). But first, we must recognize this crisis for what it is: a global
health emergency.