New Report Reveals the Growing Threat of Climate Change to Human Health
As world observes World Earth Day on 22nd of April a new report from the Lancet Countdown on Health and Climate Change has found that 10 out of 15 key indicators related to climate and health have hit record highs. These worsening conditions are hitting the hardest in communities that are least responsible for climate change—especially the 745 million people who still lack access to electricity. Meanwhile, fossil fuel use and subsidies continue to rise, increasing emissions and worsening the health risks worldwide.
This annual report, first launched in 2015, is produced by a team of 300 researchers and experts from UN agencies and academic institutions. Its goal is to track how climate change is affecting human health globally. The latest edition, released in October 2024, examines 56 key indicators.
Key Health and Climate Finding
Extreme Heat
Dangerous heat has become more frequent. From 2019 to 2023, people experienced 46 more days of health-threatening heat per year compared to a world without climate change. Developing countries are hit hardest, with many facing 100 or more additional days of extreme heat.
Older adults are especially vulnerable—those over 65 saw a 167% increase in heat-related deaths in 2023 compared to the 1990s. From 1990–1999 to 2014–2023, deaths in this age group due to heat rose by 106%.
Wildfires
Recent wildfires in Los Angeles, which killed 24 people and destroyed over 12,000 buildings, are part of a global trend. Warmer temperatures and more frequent droughts have raised wildfire risks in 124 countries since 2003.
Smoke from wildfires contains harmful pollutants like PM2.5, which can worsen respiratory and heart conditions. Even short-term exposure to these particles is linked to higher death rates.
Air Pollution
Fossil fuels are a major source of air pollution. Between 2018 and 2022, 3.8 billion people were exposed to unsafe levels of PM10, a 31% rise compared to 2003–2007.
In recent years, 2.09 million of the 6.4 million deaths linked to PM2.5 pollution were due to fossil fuel emissions. While this number has dropped slightly—mainly due to reduced coal use in highly developed countries—it still shows the ongoing health cost of fossil fuel use.
Food Insecurity
Heatwaves and droughts are making it harder to grow and distribute food. In 2023, nearly half of Earth’s land experienced at least a month of extreme drought.
As a result, 151 million more people faced food insecurity in 2022, driven by lower crop yields, water shortages, and broken supply chains.
Infectious Diseases
Warmer, wetter conditions are helping disease-carrying insects like mosquitoes thrive.
Mosquito-borne diseases cause over one million deaths and 700 million infections yearly. Warming speeds up mosquito development and extends disease transmission seasons. Between 1951–60 and 2014–2023, the risk of dengue transmission rose by 46.3% for one mosquito species and 10.7% for another. Malaria transmission became possible in 17.1% more of the Earth’s land area over the same period.
The Carbon Footprint of Healthcare
Healthcare systems are caught in a tough spot: they treat illnesses worsened by climate change, but they also contribute to it. In fact, healthcare accounts for 4.6% of global emissions, which rose 36% from 2016 to 2021. In 2021 alone, healthcare-related pollution caused the loss of 4.6 million healthy life years.
Healthcare emissions come from:
- Scope 1: Direct emissions from hospitals and clinics
- Scope 2: Indirect emissions from energy use
- Scope 3: Emissions from the production, transport, and disposal of medical supplies and services
The report finds that emissions help improve life expectancy only up to about 400 kg of CO2e per person. Beyond that, they don’t result in better health outcomes. Countries like the US, which emit over 1,600 kg CO2e per person through healthcare, can significantly reduce emissions without lowering care quality.
A Model for Sustainable Healthcare: The UK NHS
The UK’s National Health Service (NHS) is leading the way in cutting healthcare emissions. In 2022, it became the first national health system to legally commit to reaching net zero by 2045.
Their approach includes:
- Upgrading facility energy efficiency
- Using renewable energy
- Reducing staff and patient travel
- Phasing out single-use plastics and high-emission medical products
- Encouraging suppliers to go green
- Switching to low-emission anesthetics and inhalers
The NHS is also converting its 20,000-vehicle fleet to zero-emission models, with a full switch planned by 2040. By 2040, these changes could save 5,770 lives each year from improved air quality and 38,400 lives from increased physical activity.
What’s Next?
There’s a 99.7% chance the world will surpass the 1.5°C Paris Agreement target. At the current pace, global temperatures may rise to 3.1°C by 2100. This is driven by high emissions, growing energy use, and continued fossil fuel subsidies.
Political will is also fading. In 2023, only 35% of countries mentioned climate and health at the UN General Debate, down from 50% in 2022. Of the 58 national climate plans submitted in 2023, less than half referenced health.
Without urgent action, climate change and pollution could cause 30 million deaths annually by 2100. And the burden will fall most heavily on low-income countries—those least responsible for the crisis. As climate researcher Hannah Ritchie puts it: “this is the harsh inequality of climate change.”
