Global multi-city heat perception: seasonal dynamics and climate–health signals
Meizi You, ChengHe Guan, Yuming Guo, Bao-Jie He, Steven Jige Quan, John S. Ji, Jianxiang Huang, Rongbin Xu, Zhihu Xu, Tianren Yang, Longxu Yan, Kangning Huang, ... Waishan Qiu
Applies a fine-tuned BERT-based language model to 278 million geotagged social media posts to quantify how people perceive and express heat across 347 cities in 50 countries
- Applies a fine-tuned BERT-based language model to 278 million geotagged social media posts to quantify how people perceive and express heat across 347 cities in 50 countries
- Finds that heat perception extends well beyond summer: 35.4% of cities sustain multi-season perception peaks and 16.1% show counter-seasonal regimes where winter perception surpasses summer
- Shows spatial concentration of heat perception follows continent-specific modes — intensity-driven in Africa and variability-driven in South America
- Demonstrates that co-occurring extreme temperature and elevated perception yields the strongest health associations, especially for adults aged ≥70 (mortality RR = 1.479) and respiratory mortality (RR = 1.826)
- Establishes expressed heat perception as a scalable, season-resolved signal that complements temperature and identifies when heat becomes socially salient