A new analysis projects that climate-driven heat could deprive people of significant sleep by century's end, with cascading effects on cognitive development and global earnings.
Researchers led by Bowen Chu at Nanjing University connected existing data on temperature and sleep with studies on childhood rest and lifetime productivity. Under a high-emissions scenario, they estimate average annual sleep loss of 16.4 hours per person by the 2100s compared with a 2001–2010 baseline.
The largest impacts are projected for southern and eastern Africa and southern and eastern Asia. The study calculates a global economic cost from reduced intelligence of roughly $2.86 trillion in the 2100s, with greater per-person IQ losses expected in lower-income regions.
The findings rest on a no-adaptation assumption and a high-emissions pathway that could warm the world 2.4°C by 2060. The authors note that lower-emissions paths would reduce the projected harm.