In northern Vermont, where I live, old newspaper clippings show pictures of people driving trucks across Lake Champlain. Those icy, ephemeral corridors, though, seem like relics of a bygone era.
Roughly half a century ago, maybe more, the region started to warm. At first, the change was imperceptible. The lake froze every year between 1850 and 1917 and then almost every year until the late 1940s. This past decade, though, thaw years outnumbered freeze years. This February, the lake froze for the first time in seven years.
Technically speaking, a lake freezing versus not freezing is a small shift. A degree too warm and you have running water, and a degree too cold and you have the local tourist ferry entombed in ice. Lean into that split, says Grace Liu, a machine learning expert at Carnegie Mellon University in Pittsburgh. People pay more attention when shown information in black and white — such as, years the lake froze versus did not freeze — than continuous data, such as temperature increases over time, she and her colleagues reported in July 2025 in Nature Human Behaviour.
“People notice change more frequently if they are presented with binary data,” Liu says.
Getting people to notice that something is amiss is a key first step to addressing climate change, say Liu and others. But whether that attention spurs action remains an open question.
The boiling frog effect
Scientists used to believe that once hurricanes got strong enough, wildfires destructive enough, droughts frequent enough and so on, that people would wake up to the threat of climate change. Not so much, research shows.
When researchers analyzed more than 2 billion social media posts from spring 2014 to fall 2016, they found that people think of normal temperatures as those occurring just two to eight years earlier. People’s mental baseline shifts too quickly for even rapid climate change to be noticed, the team reported March 2019 in the Proceedings of the National Academy of Sciences.
The researchers referred to this apathy as the boiling frog effect. Per lore, a frog immersed in a slowly boiling pot of water fails to notice the rising heat until, perhaps, the moment of death. Analogously, this great pot known as Earth is now coming to a rolling boil, yet many people remain oblivious to the pending disaster.
That rapid normalization of abnormal extends beyond rising temperatures. Another research team surveyed roughly 500,000 Americans exposed to some 15,000 natural disasters, including storms, floods, hurricanes, tornadoes and wildfires, from 2006 to 2022. Exposure to extreme events did little to change beliefs about climate change or willingness to support pro-environmental policies, the team reported in a seminar at the Universitat de Barcelona.
“Nothing moves the needle in any significant way,” says Toni Rodon, a political scientist at Universitat Pompeu Fabra in Barcelona.
Problematically, people perceive climate change as slow even though the rate of global warming over the past two decades is unprecedented, says Rachit Dubey, a computational cognitive scientist at UCLA. “We … gaslight ourselves into thinking it’s not a big deal.”
If people so readily normalize climate change happening within a span of a few years, imagine what happens across generations. My daughter, who was 4 years old the last time Lake Champlain froze, can scarcely remember crunching across the icy expanse. Open water in late February, at least for her, is entirely normal.
Our mental shortcut
Therapists and self-help writers are quick to note that thinking in binaries is generally a bad idea. For instance, a person struggling with depression who screens just below the cutoff for a formal diagnosis isn’t necessarily flourishing.
“A lot of therapy involves helping people see areas of gray,” says psychologist Jeremy Shapiro, author of the book Finding Goldilocks, a screed against dichotomous thinking. Black-and-white thinking is a mental shortcut, he says. “It requires fewer neurons and less effort and energy to divide things in halves.”
In a distant past with scarce resources and plentiful predators, quickly parsing good from bad could make the difference between that cruelest of binaries — life and death. Nowadays, we remain, Shapiro says, “cognitive misers.”
Data patterns indicating climate threats tend to be harder to grasp than the presence of saber-toothed big cats. In February, New York City got walloped with more than 50 centimeters of snow. Yet snowfall, once the norm in the Big Apple, has become rare. In January 2024, flakes fell in the city following a 701-day snow drought. Most of the Northern Hemisphere, researchers reported that same month in Nature, seems to be heading toward a “snow-loss cliff,” where even small increases in temperature will result in ever larger snow losses.
Shapiro spends most of his time trying to get people out of the binary mindset. “Thinking in spectrums … [is] more scientifically accurate in almost all situations,” he says. But given the persistent challenge of cracking people’s apathy around climate change, he’s intrigued by the idea that climate communicators could instead work with people’s miserly tendencies.
“I think it’s a brilliant flip,” he says.
An illusion of change
As an undergraduate student at Princeton University a few years ago, Liu first noticed what she and Dubey, then also at Princeton, call the “binary climate effect.” Tasked with digging into local climate impacts for a research project, Liu scoured newspaper articles from the early 1900s. People frequently reported ice skating and playing hockey on the local body of water, Lake Carnegie, she discovered. And they reacted with surprise and dismay in those odd years when the lake failed to freeze.
Yet for Liu, a freely flowing Lake Carnegie in winter felt normal. “I’ve never seen the lake freeze enough to ice skate,” she says. When, she wondered, did surprise fade? And could that feeling be restored?
For the paper that eventually appeared in Nature Human Behaviour, she and Dubey recruited almost 800 online participants and presented them with lake freeze data from Townsville, a fictional town known for frigid winters and ice skating on the local lake. They divided participants into two groups. One group saw graphs depicting the town’s winter temperature history from 1939 to 2019 as a time series of scattered dots, and the other “binary” group saw graphs depicting whether the lake froze or not during that same period.
On a scale from 1 to 10, participants rated the impact of climate change in Townsville. Participants viewing the continuous graphs gave the town an average climate change rating of 6.6, while those viewing the binary graphs rated it 7.5. The researchers repeated the experiment with actual data from five U.S. lakes with almost 250 people and got similar results.
The team then recruited nearly 400 more participants to see if they perceived a point in time, or changepoint, when weather patterns in another fictional town abruptly shifted. There actually was no such point because the researchers set the rate of temperature increase or lake freeze likelihood as constant. Yet roughly half the participants viewing continuous data perceived a year when things began to shift. That perception jumped to almost 75 percent of participants viewing the lake freeze data, the team found. Dichotomous data, Liu and Dubey concluded, enhances an illusion of sudden change.
Those who perceived a changepoint also rated the impacts of climate change in the town as more severe than those who did not perceive such a point. The researchers didn’t track participants’ initial views about climate change. Still, the findings hint at the possibility that such illusions can open people’s eyes to the gravity of the climate crisis.
An over-simplified world
By design, presenting the world in black and white oversimplifies a complex world, Liu says. “Any time you binarize data, you are losing information.” The key, she says, is to present all the messiness of the real world alongside a more concrete template.
Concrete information, while paring down the world to something simpler and smaller, might help people identify ways to take action, suspects anthropologist Julian Sommerschuh of the University of Hamburg. In Germany, people often experience climate disasters through television and social media feeds. Faced with gargantuan datasets that the mind can barely comprehend, they often perceive any action that fails to move the needle globally as a failure.
“[German] people are apathetic because they feel overwhelmed,” Sommerschuh says.
Contrast that with farmers in western Kenya, a place where Sommerschuh has spent decades conducting ethnographic research. Though unpredictable rain poses a palpable threat to the farmers’ way of life, they remain hopeful about the future, Sommerschuh reported in March in American Anthropologist. And they talk about concrete solutions, such as planting trees, which can prevent erosion and increase crop yields for subsequent generations.
A frozen lake is, in this vein of thinking, a palpable, concrete thing. A passerby can touch icicles curtaining a sea cave and craft sculptures from enormous blocks of ice chipped off the glassy surface. But the jagged expanse is also hard to grasp. Standing atop that vast plain, one cannot help but feel small in a grander universe.
Now, with the onset of spring, all those frozen details are melting, and meteorologists are warning people to stay off the lake. As the birds usher in spring, can those of us living along the lake’s shores hold onto winter’s memory?
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