Climate Inaction Is Now Costing Millions of Lives Every Year, Warns New Global Report

The newly released 2025 Lancet Countdown on Health and Climate Change paints an alarming yet deeply factual picture of how the world’s continued reliance on fossil fuels and slow climate action are directly harming human health today—not in some distant future. The report, led by University College London (UCL) and created in collaboration with the World Health Organization (WHO), the London School of Hygiene & Tropical Medicine (LSHTM), and more than 70 research institutions and UN agencies, examines 57 indicators that collectively track the global relationship between climate change and health.

This is the ninth edition of the Lancet Countdown report, and it arrives with new measurements on extreme heat impacts, wildfire smoke, urban blue spaces, and climate finance. According to its findings, 12 out of 20 major health indicators have now reached their worst levels on record, signaling an escalation of climate-driven threats worldwide.

Heat Exposure and Rising Mortality

One of the most striking findings is the dramatic increase in heat-related deaths. Compared to the 1990s, the rate has climbed 23%, resulting in an average of 546,000 deaths per year between 2012 and 2021. The year 2024 was officially the hottest year ever recorded, pushing global temperatures beyond anything measured in human history.

Certain populations are suffering the most. Infants under one year and adults over 65 experienced over 300% more heatwave days compared to 1986–2005 averages. These are groups with the least ability to regulate body temperature and the least resilience against extreme heat. This makes them especially vulnerable as heatwaves become longer, hotter, and more frequent.

Heat is also affecting how people work. In 2024, workers globally lost 639 billion potential labor hours due to unsafe heat exposure. That loss translated into an estimated USD $1.09 trillion in global income—about 1% of the world’s total GDP. Even countries with cooler climates are feeling the economic pinch: the United Kingdom alone lost more than 5 million labor hours, costing roughly $103 million.

Wildfires, Extreme Weather, and Environmental Instability

The planet is not only heating up; it’s also becoming drier in many regions, contributing to a rise in wildfires. In 2024, wildfire smoke was associated with a record 154,000 deaths worldwide. Smoke contains tiny particles that can penetrate deep into the lungs and bloodstream, increasing the risk of respiratory and cardiovascular diseases.

At the same time, extreme rainfall—which drives flash floods and landslides—is becoming more common, along with worsening droughts. Over 60% of the world’s land surface saw increases in extreme rainfall and drought events. These conditions damage crops, disrupt food supply chains, and push communities into food insecurity.

Climate extremes aren’t isolated events anymore—they’re overlapping and compounding each other, creating a complex web of risks for millions of people.

Infectious Diseases Are Expanding Their Reach

Changing temperatures and rainfall patterns are allowing diseases to spread more easily. The report finds that the global potential for dengue transmission has increased by nearly 50% since the 1950s. Diseases such as dengue thrive in warm, humid environments, and as more regions become suitable for mosquito breeding, outbreaks become harder to predict and control.

Other diseases influenced by environmental conditions—such as Vibrio infections, often found in warming coastal waters—are also rising to record levels.

Air Pollution From Fossil Fuels Remains a Major Killer

The continued burning of coal, oil, and gas is not only warming the planet but also degrading air quality. Millions of people die each year from polluted air, and the report highlights that this remains one of the most preventable causes of death worldwide.

A notable example is the United Kingdom, where air pollution caused 28,000 premature deaths in 2022, more than half of which were directly linked to fossil fuels. Globally, unsustainable food systems—characterized by high-carbon, unhealthy diets—contributed to 11.8 million diet-related deaths the same year.

The Economic Cost of Fossil Fuel Dependence

The world is still heavily financing fossil fuels. In 2023, governments collectively spent $956 billion on net fossil fuel subsidies—more than triple the amount promised to support vulnerable nations at COP29.

This financial imbalance illustrates the gap between climate commitments and real-world decisions. Instead of investing in resilience, cleaner energy, or sustainable food systems, much of the world is still supporting the industries driving climate change.

Some Good News: Signs of Progress

It’s important to acknowledge that it isn’t all bad news. Some indicators show promising improvements. For example:

• The health sector’s greenhouse gas emissions dropped 16% between 2021 and 2022.
• Renewable energy generation reached record levels worldwide.
• About 160,000 premature deaths are prevented each year due to decreased coal use and cleaner air in high-income countries.
• Many cities have begun assessing climate risks and taking steps to adapt.

These positive developments show that meaningful change is possible and already happening in some areas—just not fast enough to counter the accelerating consequences of climate inaction.

Why Climate Change Is a Health Issue, Not Just an Environmental One

The report strongly argues that climate change should be understood as a health crisis. When policymakers frame it that way, it becomes easier to justify urgent action—because the consequences are immediate and personal, not abstract or distant.

Climate change affects:

• Respiratory health (air pollution, wildfire smoke)
• Heart health (heat stress, particulates)
• Food security (crop failures, supply disruptions)
• Mental health (displacement, disasters)
• Vector-borne diseases
• Livelihoods and income stability

A health-centered approach also highlights solutions that offer multiple benefits at once.

What the Report Recommends

The experts behind the Lancet Countdown emphasize several urgent actions:

1. Transition Away From Fossil Fuels

Governments need to reduce subsidies for fossil fuels and invest in cleaner energy sources. This is not just an environmental necessity—it’s a public health imperative.

2. Strengthen Health Systems

Hospitals, clinics, and public health networks must be equipped to withstand climate shocks, whether they’re heatwaves, floods, or disease outbreaks.

3. Promote Sustainable Food Systems

Shifting toward low-carbon, healthier diets can drastically reduce pollution and prevent millions of deaths.

4. Build Climate-Resilient Communities

Urban planning should prioritize green and blue spaces, improve early-warning systems for extreme weather, and support vulnerable populations during heat events.

5. Increase Global Support for Low-Resource Countries

Regions most affected by climate impacts are often the least financially equipped to adapt. More equitable global climate financing is needed.

Additional Context: Why These Trends Matter Long-Term

Understanding the specifics of climate-driven health impacts helps make sense of why climate inaction is so costly. Scientists have long warned that the effects of climate change would not only hit ecosystems but also destabilize economies and public health systems. This report confirms that those predictions have now become measurable realities.

Heat waves that were once rare are now common. Diseases are changing geographical zones. Food production is becoming riskier. And the economic losses from disrupted work and disaster recovery are escalating. Each of these factors compounds the others, creating a cycle that is difficult to break without decisive action.

Research Reference:
https://lancetcountdown.org/2025-report/