Climate tipping points are a specter looming over our future — thresholds beyond which the Earth’s systems switch into new states, often abruptly and irreversibly.
The long-frozen soil beneath the Arctic could rapidly thaw and release vast amounts of carbon dioxide and methane stored within it, heating up the atmosphere even more in a feedback loop. Fast-melting fresh water from Greenland’s ice (one tipping point) could disrupt the Atlantic Ocean’s circulation pattern (another tipping point), causing weather chaos around the world: Temperatures might plunge in northern Europe, the tropics could overheat, the rainy and dry seasons in the Amazon could flip, and parts of the U.S. East Coast could be submerged by rising seas.
A new paper in the journal Nature Climate Change makes the case that all these alarming events should be called something other than “tipping points.” The framing is intended to draw attention to the radical changes that global warming might bring. But a group of scientists from Canada, the United Kingdom, Switzerland, and cities around the United States argue that the concept is scientifically imprecise — and worse, it might be backfiring.
Bob Kopp, a co-author of the paper who researches climate change and sea level rise at Rutgers University, said that talking about tipping points, as scary as they are, might not inspire people to do something about climate change. That’s because fear is an unreliable motivator. It might be key to generating attention online, but it can too often leave people feeling defeated and disengaged. “Tipping points are not, as a way of looking at the world, some inherent property of the world,” Kopp said. “It’s a choice to use that framing.”
The metaphor surged in popularity after the pop-science writer Malcolm Gladwell published the book The Tipping Point in 2000, inspired by an idea from epidemiology for the moment when a virus starts spreading explosively. “When I heard that phrase for the first time, I remember thinking, ‘Wow, what if everything has a tipping point?’” Gladwell recounted in 2009. “Wouldn’t it be cool to try and look for tipping points in business, or in social policy, or in advertising, or in any number of other nonmedical areas?”
The concept was quickly embraced by scientists trying to raise the alarm about global warming. “We are on the precipice of climate-system tipping points beyond which there is no redemption,” the climate scientist James Hansen said during a lecture to the American Geophysical Union in 2005. Three years later, the climate scientist Tim Lenton co-authored a much-cited paper assessing how close the world might be to various tipping points — when the lush Amazon rainforest might turn into a dry savanna, for example, or when the warm water eating away at the underside of the West Antarctic ice sheet could lead it to collapse into the sea. (Climate researchers have also applied the idea to cultural trends that would help cut emissions, called “social tipping points,” such as accelerating the adoption of electric vehicles or plant-heavy diets.)
Kopp said that the emphasis on climate tipping points might have made sense as a call to action 20 years ago, when the consequences of climate change weren’t so obvious. But in 2024, the hottest year ever recorded, its effects are apparent, with floods, fires, and heat waves noticeably worse than they used to be. “You just need to open the newspaper to see the impacts of dangerous climate change,” Kopp said.
Such disasters can trigger the kind of collective recognition that can lead to policy changes, like how New York City poured resources into climate adaptation after Hurricane Sandy struck in 2012. Tipping points just don’t produce this kind of response, Kopp said: “We’re never going to stand up and say, ‘Today is the day the West Antarctic ice sheet is collapsing. We better do something about that.’”
Lenton, whose work has influenced how people think about the climate’s tipping points, said that Kopp’s paper misrepresented efforts he and colleagues have made to clarify what they meant by tipping points. “Most importantly, tipping points are real and are well established in both climate and social systems — readers of this paper could get the false impression that they don’t exist,” said Lenton, who now studies climate change and Earth systems at the University of Exeter in the United Kingdom, in an email.
In Lenton’s personal experience, the framing of “tipping points” can help people understand the risks of climate change. “What makes me sad about this paper is that, as is too often the case, some members of the climate community would rather pick arguments with each other than constructively work together in a common quest for the public good, against a well-organized opposition,” Lenton said.
Lenton’s paper in 2008 justified its review of what climate systems might tip because of “increasing political demand to define and justify binding temperature targets.” But there are still unknowns about how much global warming would actually trigger tipping points. Take, for example, the potential for a major slowdown in the Atlantic Ocean’s conveyor belt of currents that regulate temperatures, distributing heat from the equator to the poles, and vice versa. One study from 2022 found that the threshold for collapse could be anywhere between 1.4 and 8 degrees Celsius of warming.
Despite that, tipping points have become conflated with international goals to keep global temperatures beneath 1.5 degrees C (2.7 degrees Fahrenheit). Kopp and his colleagues found many references, from the news as well as in scientific studies, to “the 1.5-degree C tipping point.” But the temperature thresholds for tipping into catastrophe are very uncertain. What’s for sure is that with every tiny amount of global warming, the risk continues to grow.
“If people think the scientific community has been telling them that 1.5 degrees C is a tipping point, but nothing happened when we went over 1.5 degrees C, that can threaten scientific credibility at a time when actually we are facing a lot of dangers from climate change,” Kopp said.
He isn’t suggesting that people should keep quiet about the tipping points the world faces. He simply wants different terminology — perhaps a phrase like “potential surprises.” But given the widespread appeal of “tipping points,” which has made its way into more than 2,200 scientific papers at this point, switching to a new phrase would be a major challenge.
