Humans prefer their weather in something of a Goldilocks zone—a not-too-hot, not-too-cold temperature window which not only affects our physical comfort, but also our mood. Tempers can become irritable, patience may be afflicted, and behaviours could suffer from heat waves and deep freezes. New research has shown that the heat wave and deep freeze can lead to tempers fraying, poor patience and even behavior problems. The Lancet Planetary HealthThis is true in both our online interactions and in person. As temperatures rise or fall above or below a comfort zone of 54ºF to 70ºF (12ºC to 21ºC), online hate speech in the U.S.—at least on Twitter—increases accordingly.
Leonie Wenz (working group leader, Potsdam Institute for Climate Impact Research) led the research team. They began by analyzing more than 4Billion geolocated Tweets that were posted in the U.S. during a period of six years, from May 2014 through May 2020. They programed an artificial intelligence algorithm to scan the tweets for hate speech, which they defined, according to United Nations standards, as any communication that “attacks or uses pejorative or discriminatory language with reference to a person or a group on the basis of … their religion, ethnicity, nationality, race, color, descent, gender or other identity factor.”
That’s a broad definition and the algorithm could sometimes be flummoxed by it. Although the researchers were able train the algorithm to recognise hateful words and phrases, there are many meanings. Notably, software had to understand the meaning of N-word. One variant of the word, which ends in “-a”, for example, has been “reappropriated as a type of endearment in some communities,” the authors wrote. In that case, they taught the software to look for surrounding words that were “aggressive or derogatory.”
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Overall, just over 75 million tweets—or 2% of the four billion total in the six-year window—analyzed by the algorithm qualified as hate speech. However, the exact time and origin of tweets can vary greatly. This study used geolocation to determine the origin of hate-filled tweets in 773 U.S. cities. It also cross-referenced the information with data about the temperature at the locations where the tweet was written.
The study didn’t find any cities or regions that produced the most hate tweets. However, they found one critical variable: the temperature. The fewest hate tweets occurred in a narrow six-degree temperature range of 59ºF to 65ºF (15ºC to 18ºC), within the identified broader comfort zone. Outside of that 54º F to 70º F sweet spot, things could vary widely. On extremely cold days, for example—more common in the northern tier than elsewhere in the country—when temperatures ranged from 21ºF to 27ºF (-6ºC to -3ºC), hate tweets increased by 12.5%. On extremely hot days—especially in the desert southwest—when temperatures maxed out between 108ºF and 113ºF (42ºC to 45ºC)—hate tweets rose by 22%.
“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,” said Anders Levermann, head of complexity science at PIK and a co-author of the study, in a statement accompanying its release. “There are likely limits of adaptation to extreme temperatures and these are lower than those set by our mere physiological limits.”
That’s not to say we don’t adapt at all. This study separated the 773 tweets from seven cities into five climate zones. Broadly, they found that increases in hate tweets varied, with, say, people in the cold region—which covered most of the northern part of the 48 contiguous states—showing less of a bump in online misbehavior during an extreme cold snap than people in the hot-humid region, who would not be as accustomed to sudden thermometer plunges.
“This could suggest that the hate tweet increases are dependent on the temperatures we are used to,” the authors wrote.
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Limitations in the study didn’t allow researchers to use geographical information to tease out any differences in weather-related hate tweeting depending on socioeconomic status, faith, race, political party membership or more. “Groupings based on income, religion and partisan [affiliation] are not perfect since cities are never perfectly homogenous,” they wrote; their geolocated data, however, did not control for those factors.
Although it was difficult to identify the exact demographics who were sending hate tweets, it wasn’t hard to find out the target audience. According to the study, existing research shows that 25% of Blacks and 10% of Hispanics have experienced online harassment. These communities also are most susceptible to extreme weather and climate change. The study also found that members of the LGBTQ community were four times more likely than other groups to report harassment online. These same groups, the authors warn, are the likeliest to suffer from all hate tweets, including temperature-related ones—and that poses a danger to their well-being.
“Being the target of online hate speech is a serious threat to people’s mental health,” said Annika Stechemesser, a doctoral researcher at PIK and a co-author of the study, in a statement. “The psychological literature tells us that online hate can aggravate mental health conditions especially for young people and marginalized groups.”
As human-caused global warming worsens, and temperatures extremes increase, this danger will grow. “Assuming little adaptation and similar communication patterns,” they write, “this would mean that hate expressed online could increase under future global warming.” Hate is a uniquely human quality, and climate change is one of our most regrettable handiworks. These two make an awful pair.
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