New research shows that multiple climate tipping points are likely if global policies stay unchanged, with a 62% risk on average. However, more sustainable pathways could significantly reduce these risks.
New research finds that multiple climate “tipping points” are likely to be triggered if global policies continue on their current path.
Scientists evaluated the risk of tipping across 16 critical components of the Earth’s system — including the collapse of major ice sheets, the loss of tropical coral reefs, and the dieback of vast forests.
Under current policies and projected warming, their most conservative estimate shows a 62% average risk of crossing one or more tipping points. However, the study also highlights that adopting more sustainable pathways with lower greenhouse gas emissions could significantly reduce this risk.
The study, by the universities of Exeter and Hamburg, also found that carbon released by certain tipping points (Amazon rainforest dieback and permafrost thaw) is unlikely to cause enough warming to trigger other tipping points.
Preventing Tipping Points Is Still Possible
“The good news from our study is that the power to prevent climate tipping points is still in our hands,” said lead author Jakob Deutloff.
“By moving towards a more sustainable future with lower emissions, the risk of triggering these tipping points is significantly reduced. And it appears that breaching tipping points within the Amazon and the permafrost region should not necessarily trigger others.”
A “tipping point” occurs when a small change tips a system into a new state, causing significant and long-term transformation.
The study assessed tipping point probabilities in five different scenarios, known as shared socioeconomic pathways (SSPs).
Professor Tim Lenton, from Exeter’s Global Systems Institute, said: “Climate tipping points could have devastating consequences for humanity. It is clear that we are currently on a dangerous trajectory – with tipping points likely to be triggered unless we change course rapidly. We need urgent global action – including the triggering of ‘positive tipping points’ in our societies and economies – to reach a safe and sustainable future.”
Reference: “High probability of triggering climate tipping points under current policies modestly amplified by Amazon dieback and permafrost thaw” by Jakob Deutloff, Hermann Held and Timothy M. Lenton, 23 April 2025, Earth System Dynamics.
DOI: 10.5194/esd-16-565-2025
During the writing phase, Jakob Deutloff was funded by the German Research Foundation. Professor Lenton’s work was supported by the Bezos Earth Fund.
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12 Comments
“…, their most conservative estimate shows a 62% average risk of crossing one or more tipping points.”
Apparently, all CO2 emission scenarios were used in calculating the 62% average risk. However, others have made the case that the SSP5-8.5 scenario is improbable because of limitations on the long-term availability of fossil fuels. Therefore, SSP5-8.5 should be excluded from this and similar simulations.
What is the uncertainty (margin of error) associated with the above claim? I’m going to assume that the probabilities are multiplicative, meaning that the probability of more than one event is 0.62 raised to the power of the number of so-called ‘Tipping Point’ events. That is, two ‘Tipping Points’ would be 38% probability and three ‘Tipping Points’ would be 24%, etc.
Real scientists use words like “phase change” or “region of stability,” not “tipping points,” which bring up mental images of a tree or building falling over, with no possibility of restoring it.
The world’s most renowned citizens have sounded the alarm, like King Bezos, that tipping points are an undeniable risk. We do not have evidence of tipping points, and none have been observed geologically or in person, but that simply means that every witness didn’t survive to tell the tale. If we continue on the current path, there is a 62% chance the momentum will become unstoppable reaching an irrevocable critical tipping point of no return, and Columbus and his three ships will fall off the edge of the Earth. Based on the best current projection models in the year of our Lord 1492, we must change course rapidly to a more sustainable pathway, such as via the Cape of Good Hope, else the future is at risk.
Ah, “Clyde Spencer” – responds to all climate related posts, but doesn’trespond to posts of any other topic. Trying to sow doubt with “could be”, “perhaps”, and so forth, but never actually talking to the actual scientists to refute anything. No real interest or perhaps competence in science, seems like someone’s doing a job for one of the polluters. So, “Clyde”, how’s the weather in Bangalore?
The climate change ship has sailed. Some of us who have seen a glacier 20 years ago, can go back and check that it has receeded. Most of us have noticed hotter summers in our hometowns. Any one of us who knows basic science knows that we are increasing CO2 in the atmosphere and that it is a greenhouse gas.
I have noted that the glacier across which I used to walk 50 years ago is now very much a lake, and as a result the glacier-supported over- steepened mountainsides up which I used to climb when it wasn’t raining that much are slumping, as is the lateral moraine on either side of the lake. That’s been going on since the late 1880s; I got there in 1973. I suppose that in the 1880s cars were beginning to get invented and smokey western industry was cranking large volumes of smokey stuff. But the CO2 growth curve didn’t take off dramatically until 1945-50, as did antibiotic treatments and the human race has doubled its population since then.
Rob, I first visited the Fox glacier in 1979 while on sabbatical leave from from my teaching position in the geology and geography departments; I went back in 1989 and personally observed that it had retreated significantly. It was an interesting observation. However, it is essentially anecdotal evidence that has little direct bearing on the question of whether or not humans have had a significant influence on that retreat. This is not a forum conducive to working out all the details, nor would it change a lot of minds if I were to make a compelling argument. Truth be known, I’m acting like a gadfly to embarrass those who consider themselves to be scientists, by virtue of their degrees or job title, to act like scientists and be objective. That is, to objectively present facts and consider multiple working hypotheses as explanations, and to clearly state the uncertainty in their measurements, particularly averages, which mean little without the probability distribution and kurtosis.
Appreciated comment. I was on the other side of the Main Divide. Those NZ Glaciers were often higher than their lateral moraines back in the day, which was back around 1880-1890, which was about when any advancing glaciers stopped and began their shrinkage and retreat. It was interesting to see how rock-falls produced angular fragments of assorted sizes on top of the glaciers and how the rivers exiting the glacier snouts produced beautifully rounded clasts. That led to my opinion that glacier-driven erosion is produced by assorted sub-glacial rivers carrying clasts that do more erosion to the sub-strate than glacial plucking by the ice, and that that is a feature of perhaps glacial retreat in a warming pperiod. I have seen interesting large potholes drilled in bedrock in regions formally covered by ice-sheets/glaciers. I can’t see ice doing that.
Most river/stream erosion occurs during flood stage because the carrying capacity of sediment is very non-linear with respect to water velocity.
There is a locality in New England, the Baker River, where the Summer flow is generally shallow enough to walk through. However, the bed of the river is littered with boulders the size of cars and there are huge potholes — 2-3m across and probably at least 3-4m deep. The depth is uncertain because they are filled with gravel and boulders. The potholes were undoubtedly made during the late-Pleistocene to Early-Holocene as the continental glaciers were melting.
It looks like you haven’t done your homework. I DO respond to other topics, although I focus on the areas where I have some expertise. Actually, you just stole my line. I frequently complain about people who call themselves ‘scientists’ but use the qualitative language of lawyers — “could be, perhaps, and so forth” — and my ever favorites, “might,” and “possibly.” There is plenty of opportunity for “actual scientists” to call me to task for asking inconvenient questions like “What is the uncertainty (margin of error) associated with the claimed average?” So far, it hasn’t happened. Is that because they don’t have an answer that wouldn’t make them look incompetent or biased?
You have demonstrated that you don’t even understand the issues, despite your claim to know “basic science.” There is no argument among scientists about whether the climate has warmed over the last 25,000 years. There is no argument about whether or not CO2 (a potential greenhouse gas) has increased over that same period. What IS contentious is whether or not those two variables are demonstrating what is known as a “spurious” or even an inverted correlation. That is, are the two variables demonstrating a correlation that is just coincidence or possibly that temperature is driving the production of biogenic CO2. It is easily demonstrated that the seasonal changes in CO2 flux is driven by biology and is at least an order of magnitude greater than anthropogenic CO2, which is essentially constant throughout the year. After all, the ice core from Law Dome C strongly suggests that CO2 lags changes in temperature by nearly a millenium, suggesting that temperature is actually the driver! You present NO evidence on what the net effect is for the interaction of the two variables of interest after participating in numerous feedback loops. Global Circulation Models attempt to do that, but have consistently run too warm, except for the Russian model, which even the modelers admit. It is all a house of cards held up by the so-called ‘news’ media and journal editors that make it difficult to get contrary views published.
You have chosen to insult me and question my competence in science while presenting the flimsiest of evidence to support your belief system, despite trying to impress readers with your implied mastery of “basic science.” Now it is time to demonstrate that you really understand that which you are defending. If you decide to respond, try using some specific, germane facts that demonstrate your mastery of “basic science” and the complexities of the subject.
As you are aware, I favour the precautionary principle having proved the point of wearing decent clothes and helmet when both riding motorcycles and climbing friable mountains. The same applies to societies, even if the greenies are incorrect about our future; and if application of that principle spawns new useful technologies such as solar power systems etc, then I have no problems with the word “could”. It stimulates thought and for some, action and industry, even if “could” is not rigorous scientifically.
And as you are aware, I can’t support your position because you haven’t been able to define a threshold for when to invoke the Precautionary Principle. That is, you promote sanctimonious hand waving without concrete advice about when the cost is too high or the effort is a waste of money because the PP could not be sufficient to prevent the potential outcome. It is akin to saying the one in in favor of “motherhood and apple pie” without defining what that means. To be practical, PP behavior has to actually be able to prevent some problem. Building on a river flood plain, and putting a 1 meter-high dike around the house when hydrologists predict a 2m-high flood every decade is a waste of time and money because it will not prevent having one’s home flooded. Building a dike high enough and strong enough to prevent flooding in the expected life-time of the home defeats the purpose if the dike costs more than than the home is worth and prevents one from enjoying the scenery. What is appropriate is a cost-benefit analysis to make the decision whether to spend any money at all or to not build on a flood plain.
I would submit that wearing a protective helmet is essential for spelunking, generally required by law for working in a quarry or open-cast mine despite workers having been killed by fist-sized cobbles falling from a high-wall killing workers wearing an ‘approved’ helmet. Motorcycle helmets are more problematic in that in some accidents they may prevent traumatic head injury, but the outcome is still fatal for the rider. That is, following the PP is insufficient to accomplish its purpose and one could have avoided the expense and inconvenience and have the same outcome.
My threshold. When I am scared. Terribly irrational and unscientifc but commonly a human weakness. I don’t spelunk for that reason; what goes down don’t necessarily come up. I could always fall off a mountain. It’s why I used a rope and a belay and climbed with a partner in certain instances, and carried the necessary equipment to do to SHOULD the opportunity arise that it COULD be useful. Expensive stuff to have carted around at times, and on occasion certainly not cost-effective in cash or sweat.
Flood-plains; best left to farming . Yes, don’t ride a motorcycle………..
Sanctimonius hand waving………….so be it.
Looks like SOME folks need to hear a few verses of “Soft Kitty”.