Hateful tweets multiply in extreme temperatures, US analysis finds

The research used machine-learning algorithms to identify around 75 million English-phrased hate tweets – around 2% of the sample – in 773 US cities between 2014 and 2020. Photograph: Olivier Douliery/AFP/Getty Images

Hateful tweets multiply dramatically as temperatures become more extreme, an analysis of 4bn geo-located tweets in the US has found.

Scientists logged rises of up to 22% in racist, misogynist and homophobic tweets when temperatures rose above 42C, and increases of up to 12% when the mercury fell below -3C, according to a study by The Lancet Planetary Health.