Overview
- The study projects that 86% of 221 global marathons, including all Abbott World Marathon Majors, will see reduced odds of ideal temperatures by 2045.
- Researchers define performance sweet spots near 4°C for elite men and 10°C for elite women and use historical records, climate models, and the Climate Shift Index to assess future odds.
- Heat at the 2025 Tokyo and Berlin marathons was made two to three times more likely by human-caused warming, pushing race days beyond peak-performance thresholds.
- Projections show Tokyo’s ideal-day odds for elite men dropping from 69% to 57% by 2045, while Berlin’s for elite women fall from 40% to 29%.
- Starting closer to sunrise can improve chances for elite men in some cities but can reduce them for elite women, highlighting limited adaptations and the need to cut emissions for lasting relief.