Overview
- A Stanford-led paper in The Lancet Planetary Health recalculated heat exposure using lab data for older adults and found previous estimates seriously undercounted risk.
- Under 1.5°C of warming roughly 22% of people aged 60 and over—about 290 million—would face at least 180 hours a year of intolerable heat, the study reports.
- The authors say each extra degree of warming adds about one billion more people to the group who will get roughly another month of heat and humidity beyond what their bodies can tolerate.
- At 3°C of warming parts of South Asia and the Persian Gulf could see day-and-night dangerous heat for about three months a year, putting countries with high poverty and low cooling access at greatest risk.
- Because older adults sweat less, have weaker circulation, and often have chronic disease, the study urges rapid emissions cuts, targeted heat plans, and broader indoor cooling infrastructure to reduce deaths, health-system strain, and possible climate-driven displacement.