Climate change health risks are accelerating as the global response falls short

The 2026 Lancet Countdown finds that climate-related health risks have increased and accelerated across many indicators since the Paris Agreement was adopted ten years ago. The past 11 years have been the hottest on record, with heat, drought and water extremes increasingly threatening food security, livelihoods and lives. In 2025, extreme drought affected more than half of the world’s land for at least a month. 

A new satellite analysis shows growing extremes in water storage. Since 2003, 43 percent of global land has become drier over the long term, while 37 percent has become wetter. These changes affect more than 80 percent of the world’s land, threatening crops, food supplies and sanitation. Very heavy rainfall has also become more common, affecting almost 17.2 percent of global land annually in 2016-2025, up from 14.8 percent in the previous decade. This increases the risk of floods, landslides and waterborne diseases.

Heat takes a growing toll on lives and livelihoods

Climate change is estimated to have caused almost three million heat-related deaths between 2016 and 2023. Heat was associated with an estimated 540,800 deaths per year on average over this period, with 68 percent attributable to climate change, up from 55 percent in 2006-2015.

Heat also undermines people’s ability to work. In 2025, heat-related reductions in labour productivity cost the global economy an estimated USD 1.07 trillion in potential income, equivalent to 0.91 percent of global economic output. South-East Asia and Africa were hit hardest, with losses equivalent to 3.9 and 3.2 percent of GDP, respectively, compared with 0.2 percent in Europe. Agriculture and construction accounted for the largest shares of losses. In Africa, agriculture alone accounted for 71 percent of heat-related potential income losses.

PIK researchers track developments in climate-and-health research

The Lancet Countdown monitors the health impacts of climate change and the health benefits of climate action through a set of 54 indicators. The 2026 report introduces four new indicators covering water availability on land, greenhouse gas emissions from the healthcare sector, climate-and-health research funding, and legislative engagement with health and climate change.

PIK scientists contributed to the report for the fifth time, using artificial intelligence to map developments in climate-and-health research. Scientific publications on human health and climate change increased by 28 percent between 2024 and 2025, while the share examining the health effects of climate mitigation declined. The analysis also found that the share of publications focusing on low and middle Human Development Index (HDI) countries rose from 15 percent in 2006-2015 to 19 percent in 2016-2025. These countries face particularly severe climate impacts.

Clean energy brings health benefits, but progress remains insufficient

The report identifies progress in clean energy, health-system preparedness and health-protective regulation, but concludes that action remains too slow and uneven to offset growing risks.

Global clean-energy investment grew by 7.2 percent in 2025 and was 82 percent higher than investment in fossil fuels, which stood at USD 1.16 trillion. Renewable electricity’s share of global generation rose from 5.5 percent in 2016 to 13.5 percent in 2023. Cleaner air is already saving lives: in at least 77 countries where air pollution from fossil fuels has declined since 2016, an estimated 323,000 deaths are prevented each year.

Yet the transition away from fossil fuels remains inadequate. Fossil fuels still supply more than 80 percent of global energy, climate-heating emissions reached a record high in 2024, and air pollution from fossil fuels continues to cause an estimated 2.73 million deaths annually.

The authors call for climate change to be formally recognised and addressed as a global health emergency, with health placed at the centre of climate decisions, from emissions reductions to funding priorities.

The Lancet Countdown was established in 2016 in partnership with Wellcome, which continues to provide core financial support.