Scientists have uncovered a clear link between rising temperatures and worsening moods. They examined over a billion social media posts from 157 countries. The analysis showed that whenever temperatures exceeded 35°C, expressed emotions turned more negative. Low-income regions experienced the strongest shifts, with far greater negativity than wealthier countries.
Researchers from MIT and international institutions gave each post a sentiment score and matched it to weather data. Compared with cooler days, hot days produced significant increases in negative content. The findings point to a direct emotional consequence of climate change.
Anger, Aggression, and Heat
Past research supports this connection. Drivers honk more during hot days, and journalists choose harsher words when covering events in hot conditions. Studies have linked heatwaves to crime, violent incidents, and even suicides. Historic uprisings across centuries were also more likely to erupt in summer months.
Scientists suggest heat may affect brain chemistry or hormones, reducing stability and heightening aggression. Still, they caution these effects are complex and often combine with larger social pressures.
The Future Outlook
Using climate models, researchers predict global sentiment could decline by over 2% by the year 2100 due to sustained heat. Vulnerable groups underrepresented on social media—especially children and older adults—may suffer even greater impacts.
Experts warn that adaptation must go beyond physical safety. Preparing societies for the emotional strains of rising heat will be vital in the decades ahead.
