Drop a frog into a pot of boiling water, and it will immediately jump out. But if you start with cool water gradually warmed to its boiling point, the unsuspecting amphibian will acclimate to its environment, remaining in the pot until the situation passes the point of no return—or so the urban legend (erroneously) goes.
Although this fable has been definitively debunked, a new study published in the Proceedings of the National Academy of Sciences suggests the metaphor has its merits—at least when it comes to humans’ evolving perceptions of extreme weather events. As Ula Chrobak reports for Popular Science, a survey of 2.18 billion tweets posted by users in the continental United States revealed that after experiencing just two to eight years of extreme temperatures, people appear to stop viewing climate change-driven phenomena as an anomaly.
Earther’s Brian Kahn writes that researchers led by Frances Moore of the University of California, Davis, focused their analysis on tweets dating to March 2014 through November 2016. Upon identifying a selective sample of 6,000 weather-related posts, the scientists, according to The New York Times’ Kendra Pierre-Louis, compared users’ local temperatures at the time a tweet was sent to baseline temperatures recorded in those same areas between 1981 and 1990.
Unsurprisingly, Amber Jorgenson notes for Discover magazine, the team found that Twitter users were more likely to post about the weather on days that were unseasonably hot or cold. If extreme temperatures became an annual occurrence in posters’ locales, however—consider a town where winter temperatures drop unexpectedly one year and never quite return to pre-drop levels—individuals seemed to gradually adjust, with tweets commenting on the weather tapering off after two to eight years of exposure to the now-normalized conditions.
Another insight offered by the study relates to extreme weather’s effect on humans’ state of mind. As Earther’s Kahn explains, the researchers used a technique known as sentiment analysis to gauge whether bouts of unusually hot or cold temperatures correlated with users’ mood.
The team found that individuals experiencing extreme weather conditions expressed more negative sentiments than their “normal” weather counterparts regardless of how long they had been continually exposed to abnormal temperatures. This suggests, the authors write in the study, that while humans may find extreme weather less remarkable over time, they remain ill-equipped to deal with its adverse effects.
“We saw that extreme temperatures still make people miserable, but they stop talking about it,” Moore says in a press release. “This is a true boiling-frog effect. People seem to be getting used to changes they’d prefer to avoid. But just because they’re not talking about it doesn’t mean it’s not making them worse off.”
It’s worth noting that the study has its limitations. Yotam Ophir, a science communication researcher from the University of Pennsylvania who was not involved in the survey, tells Earther that Twitter users tend to be “young, highly educated, and urban. So what we can learn from a study such as this one is how people who use Twitter talk about weather on Twitter.”
Still, Discover’s Jorgenson argues, the scientists’ findings could have important implications for the fight against climate change: If people start normalizing extreme weather, they may adopt a warped view of our warming planet, making it more difficult for researchers and policymakers to enact legislation aimed at combating the phenomenon. Instead of judging weather in relation to recent years, the researchers advise, look to longer-term patterns dating back decades or even centuries.