What happened: The Lancet Countdown report, produced with the World Health Organization and led by University College London, estimated a record 710,000 heat-related deaths worldwide in 2023, UN News reported on Oct. 28. For the first time, more than seven in 10 of those deaths were attributed to human-caused climate change. The report tracks 54 indicators linking climate and health.

Why it matters: It finds extreme drought affected 51.8% of the world's land for at least a month in 2025, and conditions for dengue spread by one mosquito species rose 24% since the 1980s. It also says the 100 largest oil and gas companies plan to produce 150% more fossil fuels by 2040 than a 1.5°C path allows.

How much agreement is there? Some disagreement. The health trends are drawn from many research groups; the debate is over response. The authors want climate change formally declared a global health emergency before the COP31 talks, and they also note a record $2.1 trillion in clean-energy investment last year.

Could someone help? Communities and young volunteers can check on older or isolated neighbors during heat waves, and health groups can push for the national health adaptation plans the report tracks.