Nations worldwide must finance and implement climate adaptation measures for health systems or risk losing millions of lives as extreme weather, rising temperatures, and intensifying heat threaten healthcare access for nearly half the global population, according to a report published Friday by the World Health Organization and Brazil.

The special report, released at the COP30 summit in Belém, follows Thursday’s launch of the Belém Health Action Plan, which won backing from roughly two dozen countries but secured no financial commitments from governments.

The only funding to support the plan came from philanthropies: a $300 million one-time grant. The report estimates health system adaptation needs at $22 billion per year by 2035.

“The climate crisis is a health crisis – not in the distant future, but here and now,” said Dr Tedros Adhanom Ghebreyesus, WHO Director-General. “This special report provides evidence on the impact of climate change on individuals and health systems, and real-world examples of what countries can do – and are doing – to protect health and strengthen health systems.”

The past decade has been the hottest on record, with global temperatures exceeding 1.5°C above pre-industrial levels for the first time in 2024.

Updated Climate Tracker projections published at the UN climate summit on Wednesday show the world on track for 2.5°C of warming, while the UN Environment Programme projected last week that a business-as-usual scenario has the world heading for 2.8°C. Every fraction of a degree endangers millions.

“Many health systems are fragile, lacking climate-trained personnel, resilient infrastructure and adequate surveillance,” said Simon Stiell, executive secretary of the UN Framework Convention on Climate Change. “Watching super typhoons and flash floods rip through hospitals and local health clinics is heartbreaking, but lamenting is not a strategy. We need real solutions.”

“The real challenges people face, such as extreme heat, air pollution, infectious diseases, mental health and food insecurity – humanity can only win this global climate fight if we connect stronger climate actions to people’s top priorities in their daily lives, and there are few higher priorities than our health,” Stiell said.

The report does not present new evidence, functioning instead as a synthesis of the best available science and data on the risks posed to unprepared health systems by climate change, drawing on academic literature, government and UN reports, and real-world case studies.

“Recent tragedies show that now is the time to implement policies and actions that address the impacts of climate change on health,” said Alexandre Padilha, Brazil’s health minister. “The Belém Health Action Plan and this report offer countries the tools they need to turn scientific evidence into concrete action.”

As storms batter coastlines, floods displace communities, and droughts fuel conflict and hunger, the report paints a picture of health systems under mounting strain. The familiar but alarming statistics form the case to policymakers to invest in adaptation and join the Belém plan.

More than 540,000 people now die annually from extreme heat, a 63% rise since the 1990s. Between 3.3 and 3.6 billion people live in regions highly vulnerable to climate change.

One in twelve of the world’s 200,000 hospitals face the risk of total shutdown due to extreme weather events under high-emissions scenarios, with more than 70% of at-risk facilities located in low- and middle-income countries. Hospitals and health facilities are also 41% more likely to suffer damage from extreme weather events than in 1990.

“Climate change is an unavoidable reality that challenges public health and adds pressure on already overwhelmed systems,” Padilha said, calling policies to protect the health sector one of the “most strategic decisions of the 21st century.”

“Protecting lives, reducing inequalities, and bolstering the resilience of health systems are no longer just goals – they have become ethical and democratic imperatives,” he said.

Mitigation left out of the main Belém text 

While the report and Belém Health Action Plan focus on preparing health systems for climate impacts, the synthesis document draws a clear conclusion about what would most protect those systems: cutting emissions.

“The evidence is clear: urgent and sustained mitigation across all sectors is the single most important health adaptation intervention,” states the executive summary. “There are profound physical, financial, and technological limits to adaptation, and health systems cannot remain resilient in a world of unchecked warming.”

By reducing emissions, health systems face less extreme weather to withstand, fewer heat deaths to treat, and smaller disease burdens to manage – making adaptation needs less severe in the first place.

That finding sits awkwardly with the Belém Health Action Plan itself: it contains no reference to phasing out fossil fuels, the main driver of climate change.

That omission came at the explicit instruction of the Brazilian COP30 presidency, according to people familiar with the negotiations, likely to open the door for more nations to sign on who will not commit to language on fossil fuel phase-out.

What the report identifies as “the most effective measure” to protect health systems has been excluded from the political framework, which requires endorsement from governments, and relegated instead to a supporting document with no political weight.

“When COP30 delegates leave Belém, success will be measured by the courage governments have demonstrated to act on what is already known: that fossil fuels are destroying people’s health,” said Jeni Miller, health lead at the Global Climate and Health Alliance. “To ignore these realities would be to betray both science and humanity.”

A $20 billion gap 

Direct health sector adaptation interventions will require more than $22 billion annually by 2035, according to the report, approximately 7% of total adaptation financing needs in climate-vulnerable countries.

Current health-specific climate finance reaching those countries totals around $500 to $700 million annually, representing 2% of adaptation funding and 0.5% of multilateral climate finance.

Climate and health finance has grown considerably in recent years, rising tenfold from less than $1 billion in 2018 to $7.1 billion in commitments between 2018 and 2022, according to analysis published earlier this year by the Rockefeller Foundation, WHO and other partners.

In 2022, this included $4.8 billion from bilateral donors, $600 million from multilateral development banks, $1.5 billion from multilateral health funds, and $130 million from philanthropies.

The share of climate finance targeting the health sector increased from 1% in 2018 to 9% in 2022, the only sector apart from education to see an increase. Yet these flows remain far below estimated needs, and more than 90% of health adaptation funding from development banks arrives as loans rather than grants.

“The evidence is clear that we have been too slow to act on climate change and we are now ill-equipped to cope with rising temperatures across the world,” said Alan Dangour, health and climate lead at the Wellcome Trust.

The report identifies persistent gaps in readiness. Only 54% of national health adaptation plans assess risks to health facilities. Fewer than 30% of health adaptation studies consider income, 20% consider gender, and less than 1% include people with disabilities. More than 60% of National Adaptation Plans have no formal tracking or evaluation in place.

“Extreme heat, air pollution and infectious disease all hit the most vulnerable hardest: children, pregnant people, older adults, outdoor workers, and communities with the fewest resources,” Dangour said.

“At COP30 and beyond, governments must act on the science – cut emissions, invest in adaptation, and put health at the heart of climate action. Lives, economies, and our future depend on the solutions we deliver now.”

Image Credits: COP30, COP30.