Lancet Countdown report calls for climate change to be declared a global health emergency as heat deaths near three million since 2016

Key facts

• The 10th edition of the Lancet Countdown on Health and Climate Change report, produced by 146 researchers from 30 countries and published ahead of the COP31 climate summit, calls for climate change to be formally declared a global health emergency.
• Heat caused a record 710,000 deaths in 2023, with over 70% linked to human-caused climate change, and nearly three million heat-related deaths occurred globally between 2016 and 2023 since the Paris Agreement.
• Warming-related productivity losses cost the global economy over one trillion dollars per year in the past three years, with Southeast Asia and Africa losing the equivalent of 3.9% and 3.2% of GDP respectively.
• Fossil fuels still supply 80% of global energy and their air pollution causes 2.73 million deaths per year, though about 323,000 deaths have been avoided in at least 77 countries where such pollution fell since 2016.
• Clean energy investment reached $2.1 trillion in 2025, double that of fossil fuels, and 56 of the WHO's 194 member states have adapted health and early-warning systems for extreme events since 2016.
• India ranks among the top countries with the highest heatwave exposure for infants and older adults, along with China, the U.S. and Russia; in 2025 older adults faced 10.8 billion person-days of heatwave exposure and infants 1.1 billion.
• Funding for climate-related health research rose sevenfold to $316 million in 2024, but 84% goes to researchers in wealthy countries.