Climate Inaction Is Killing Millions: Lancet-WHO Report Calls for Health-Focused Climate Action

As the planet approaches critical climate thresholds, the 2025 Lancet Countdown on Health and Climate Change — released in partnership with the World Health Organization (WHO) — delivers a powerful and sobering message: the health of humanity is already paying the price of climate inaction. The report makes a compelling case for placing health at the heart of climate strategies ahead of COP30 in Belém, Brazil.

According to the report, which is the most comprehensive to date, 12 out of 20 key health-climate indicators have reached record highs. These trends underscore the urgent need for decisive climate action to avoid further catastrophic impacts on health systems, economies, and vulnerable populations worldwide.

Warming World, Dying Populations: The Grim Toll of Climate Inaction

The 2025 report paints a stark picture of a world already suffering from intensified climate impacts:

• Heat-Related Mortality Soaring: Compared to the 1990s, heat-related deaths have surged by 23%, with an average of 546,000 deaths annually attributed to heat exposure. The year 2024 alone saw the average person experience 16 days of dangerous heat directly attributable to climate change. Vulnerable groups — especially infants and older adults — endured over 20 heatwave days per person, marking a fourfold increase in just two decades.

• Food Insecurity Linked to Drought and Wildfires: Prolonged droughts and heatwaves in 2023 were associated with an additional 124 million people facing moderate or severe food insecurity, as rising temperatures continue to devastate agricultural productivity and water supplies.

• Economic Fallout: Heat exposure in 2024 caused the loss of 640 billion labor hours, equivalent to a productivity loss of US$ 1.09 trillion. The direct economic cost of heat-related mortality among older adults was estimated at US$ 261 billion.

• Fossil Fuel Subsidies vs. Climate Finance: Global governments spent US$ 956 billion on fossil fuel subsidies in 2023 — more than three times the amount pledged annually to support climate-vulnerable nations. Startlingly, 15 countries allocated more to fossil fuels than to their entire national health budgets.

Dr. Jeremy Farrar, WHO's Assistant Director-General for Health Promotion and Disease Prevention, emphasized:

"The climate crisis is a health crisis. Every fraction of a degree of warming costs lives and livelihoods. Climate inaction is killing people now in all countries. However, climate action is also the greatest health opportunity of our time."

Climate Action Is Already Saving Lives — But Needs Acceleration

Despite the grim statistics, the report also showcases encouraging signs of progress:

• Air Quality and Lives Saved: From 2010 to 2022, improved air quality resulting from reduced coal use led to 160,000 fewer premature deaths annually.

• Renewable Energy Advancements: Renewable sources now supply 12% of global electricity, creating 16 million jobs and reducing emissions at scale.

• Growing Climate Awareness in Health Education: In 2024, two-thirds of medical students received education on climate and health, preparing a new generation of health professionals to lead in climate resilience.

Dr. Marina Romanello, Executive Director of the Lancet Countdown at University College London, called for rapid systemic shifts:

"We already have the solutions at hand to avoid a climate catastrophe… Rapidly phasing out fossil fuels, shifting to healthy, climate-friendly diets, and transforming agriculture could save over ten million lives annually."

Cities and Health Systems Leading the Way Amid Sluggish Governmental Action

While national governments are falling behind on climate promises, cities, communities, and the health sector are stepping up. The report reveals:

• Cities Taking Action: Out of 858 cities surveyed, 834 have conducted or plan to conduct climate risk assessments, signaling localized leadership in climate adaptation.

• Healthcare Sector Reducing Its Own Footprint: Global greenhouse gas emissions from the health sector fell 16% between 2021 and 2022, while care quality improved — demonstrating that decarbonization need not compromise service delivery.

• Health System Preparedness: WHO reports that 58% of Member States have completed Vulnerability and Adaptation Assessments, while 60% have finalized Health National Adaptation Plans — showing increased awareness and strategic planning.

COP30 in Brazil: A Defining Moment for Health-Centered Climate Policy

The findings are released ahead of COP30, to be held in Belém, Brazil, where health is expected to take center stage in global climate policy. The WHO will build on this report with a COP30 Special Report on Climate Change and Health, outlining key investments and policies needed to protect health, reduce inequities, and realize the Belém Action Plan — the anticipated flagship outcome of the summit.

This year's report, now in its ninth edition, is produced by University College London in collaboration with WHO, Wellcome, and 71 academic institutions and UN agencies, providing an authoritative annual benchmark on the health dimensions of climate change.

A Call to Action: Climate Solutions Are Health Solutions

The 2025 Lancet Countdown report issues a clear call: health must become a primary driver of climate policy. From reducing emissions to transforming food systems and strengthening health services, every action taken for the climate can yield massive health dividends — but time is of the essence.

With momentum building toward COP30, global leaders are faced with a defining choice: continue business as usual and deepen the health crisis — or embrace bold, evidence-backed health-centered climate action that protects people and the planet alike.