From fossil fuels to fatalities: WHO highlights climate’s human toll

The World Health Organisation (WHO) and global partners released the 2025 Lancet Countdown on Health and Climate Change report, warning that continued reliance on fossil fuels and slow adaptation to climate change were already causing devastating health impacts worldwide. The report, produced in collaboration with WHO, found that 12 of 20 key health indicators had reached record levels, highlighting the human cost of climate inaction.

Dr Jeremy Farrar, WHO Assistant Director-General, stated that "every fraction of a degree of warming costs lives and livelihoods", emphasising that climate action offered the greatest opportunity to save lives through cleaner air, healthier diets, and resilient health systems.

The report showed that heat-related deaths had risen 23% since the 1990s, reaching an average of 546,000 per year. In 2024, the average person experienced 16 days of dangerous heat, with infants and older adults facing over 20 days. Droughts and heatwaves contributed to food insecurity for 124 million people in 2023, while heat exposure caused 640 billion potential lost labour hours, equivalent to US$1.09 trillion in productivity losses.

The report also highlighted the disparity between fossil fuel subsidies and climate finance: governments spent US$956 billion on fossil fuels in 2023, more than triple the global climate finance pledged.

Despite these challenges, climate action yielded measurable benefits. Reduced coal pollution prevented an estimated 160,000 premature deaths annually between 2010 and 2022, renewable energy created 16 million jobs, and health-related greenhouse gas emissions fell 16% globally.

As COP30 in Brazil approached, WHO and partners urged placing health at the center of climate policy, emphasising that rapid clean energy adoption, sustainable diets, and resilient health systems could save millions of lives while curbing climate change.