Scientists discovered that heatwaves influence emotions worldwide. They studied over one billion social media posts from 157 countries. When temperatures crossed 35°C, negative moods rose, especially in poorer regions. The research showed heat dampens positivity and sharpens irritability across cultures.
MIT researchers and international partners rated posts from X and Weibo. They linked each sentiment score to local weather. Results revealed that low-income countries experienced triple the emotional impact compared to wealthier nations.
Heat and Human Reactions
Previous studies already tied hot days to bad tempers. Drivers honk more in heat, journalists write with harsher words, and crime rates rise. In Greece, murders were far more common on days above 25°C. Global history shows uprisings often peak in summer months. Hot weather has also been linked to higher numbers of suicides.
Scientists suggest that heat may alter brain chemistry, reducing serotonin and increasing hormones linked to aggression. However, they warn the link may be complex, with social and economic stress also involved.
The Road Ahead
Climate models predict that rising temperatures could reduce global positivity by over two percent by the year 2100. Groups most vulnerable to heat, like children and older adults, are underrepresented in online data. The actual emotional toll may therefore be greater.
Experts stress the need to prepare for heat’s hidden effects. Adapting to both the physical and psychological challenges of a warming world will be essential.
