Hate speech spikes on social media when temperatures rise above 30 degrees Celsius (86 degrees Fahrenheit), according to researchers at the Potsdam Institute for Climate Impact Research.

The study published in The Lancet Planetary Health earlier this month also suggests that heat is associated with psychiatric hospitalizations, increased suicide rates and more domestic violence, Bloomberg reports.

And aggressive behavior online has also been linked to violence offline, found the study which was conducted on a sample of 4 billion tweets between 2014 and 2020 from US-based users.

According to the Council on Foreign Relations, a New York-based think tank, the exasperated messages have led to more violence against minorities, including mass shootings, lynchings and ethnic cleansing.

They used artificial intelligence to identify around 75 million hate messages in English, using the United Nations’ definition of online hate, which includes racial discrimination, misogyny and homophobia.

They then analyzed how the number of tweets changed as local temperatures rose or fell.

The researchers found that online hate speech increased as daily high temperatures rose above 21C (70F) – a ‘feel good’ point. Hate messages increased by 22% in warm weather, compared to average hate online during mild weather periods. Across all climate zones and socioeconomic groups in the United States, online tensions escalated even more when temperatures exceeded 30°C. Researchers observed that online hate speech increased by up to 24% – from the point of well-being – when temperatures reached 42°C to 45°C in US regions with hot and dry climates like some parts from Texas, Arizona, New Mexico and California. Last year, a study by the same researchers in Europe came to similar conclusions.

Social media reactions indicate how well people can adapt to high temperatures, said Annika Stechemesser, the study’s lead author.

She said if the temperatures get too hot or too cold, it has been found that there is an increase in hate speech online, regardless of socio-economic differences, religion or political beliefs.

“When discussing climate change, it’s important to remember that we feel the effects everywhere, not just in places where big disasters happen,” Stechemesser said. “There are places where the social consequences of the heat haven’t been discussed very thoroughly, especially how we can live together as a society and manage our well-being in the future.”

The researchers analyzed the tweets as a whole and did not look at specific incidents. That means there’s no way of knowing whether the weather escalated online tensions after the May 2020 killing of George Floyd, for example, or before the attack on the US Capitol in January 2021. Still, some conclusions can be drawn. ahead of the U.S. midterms on Nov. 8.

“Our results show that if September is particularly hot, we can expect to see more hate on Twitter,” Stechemesser said. “But the research doesn’t really show what kind of hate it is or on what topics – we don’t yet know if the hate we’re seeing is related to political issues.”

Europe, China and the United States have experienced drought and a series of heat waves this summer amid global warming of around 1.1°C on average since pre-industrial times.

The direct relationship between heat and hate online has also been documented in China, where researchers analyzed over 400 million tweets from a sample of 43 million users posting to the world’s largest microblogging platform. country, Sina Weibo. They concluded that days with temperatures above 35°C, rain, higher wind speeds, overcast skies and air pollution make people grumpier online.

“Of course people can to some degree consciously decide whether they want to be nice or not, but we still find that you’ll have more hateful behavior if you’re in a certain temperature range,” Stechemesser said. “The first thing to do is to limit global warming, this is the most obvious approach to solving this problem.”