Global warming is fuelling an increase in online hate crimes, according to new research.

Incidents soar by more than a fifth when the mercury index rises – shedding fresh light on the phenomenon.

Climate change is getting people hot-under-the-collar during conversations on social media. Temperatures above 30°C (86°F) are consistently linked.

It applies to all climate zones irrespective of socioeconomic differences such as income, religious beliefs or political preferences.

The findings, published in The Lancet Planetary Health, have implications for social cohesion – suggesting there will be more aggression and violence unless greenhouse gas emissions are dramatically reduced.

Scientists used a computer neural network to analyze four billion tweets from users in the US.

First author Dr. Annika Stechemesser said: “People tend to show a more aggressive online behavior when it’s either too cold or too hot outside.

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The AI (artificial intelligence) algorithm identified around 75 million English phrased hate tweets in a data set of more than 4 billion posted between 2014 and 2020.

They then analyzed how the number changed when local temperatures increased or decreased.

Using official UN guidelines, hate speech was defined as discriminatory language with reference to a person or group on the basis of their religion, ethnicity, nationality, race, color, descent, gender or other identity factor.

Dr. Stechemesser said: “We found both the absolute number and the share of hate tweets rise outside a climate comfort zone.

Low levels happened in a ‘feel-good window’ of 12-21°C (54-70 °F) – with the fewest occurring when it was between 15 and 18°C (59-65°F) outside.

It points to “limits of temperature adaptation capability,” say the team at the Potsdam Institute in Germany.

Co-author Professor Anders Levermann said: “Even in high-income areas where people can afford air conditioning and other heat mitigation options, we observe an increase in hate speech on extremely hot days.

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