Breaking the Planet: Scientists Issue Dire Warning of Risks of Triggering Irreversible Climate Tipping Points
Stringent emissions reductions this decade is necessary for planetary stability, and overshooting 1.5°C risks locking in devastating collapse of key planetary systems, a new study finds.
The Pine Island Glacier, along with neighboring Thwaites glacier, connects part of the West Antarctic Ice Sheet with the ocean. These glaciers are starting to break apart as the planet heats up. Credit: European Space Agency via Flickr, CC BY-SA 2.0
Urgently slashing greenhouse gas emissions this decade is “critical for planetary stability” and every additional increment of warming above 1.5°C elevates the risk of triggering climate tipping points, scientists warn.
In a new peer-reviewed study published on August 1 in Nature Communications, researchers assess climate tipping risks – the probability of triggering abrupt, irreversible, and self-reinforcing shifts in key physical systems of the planet that, once altered, would render much of the Earth dangerously unstable and potentially uninhabitable. Understanding these risks is one of the most challenging, important, and frankly terrifying parts of climate science. Crossing climate tipping points essentially means reaching the point of no return, where climate destabilization spirals out of control. While warming itself might be reversible, breaching tipping thresholds locks in devastating consequences for the entire planet.
“Consequences of climate tipping would be severe and potentially include a global sea level rise of several metres, ecosystem collapse, widespread biodiversity loss, and substantial shifts in global heat redistribution and precipitation pattern,” the new study explains.
Researchers focused on four interconnected “tipping elements” – the Greenland Ice Sheet, the West Antarctic Ice Sheet, the Atlantic Meridional Overturning Circulation (AMOC), and the Amazon Rainforest – and analyzed the risks of catalyzing abrupt destabilizations, or “tipping,” of these planetary systems under modeled future emissions scenarios.
They found that under current climate policies and emissions trajectories, there is significant tipping risk (45%) by 2300, even if global mean temperature returns to below 1.5°C in the long-term. Furthermore, the study states: “Every 0.1°C of additional overshoot above 1.5°C increases tipping risk, and greenhouse gas emissions need to reach net zero as early as possible and maintain it to minimize the risk of climate tipping points.”
“We see an increase in tipping risk with every tenth of a degree of overshoot above 1.5°C. But if we were to also surpass 2°C of global warming, tipping risks would escalate even more rapidly. This is very concerning as scenarios that follow currently implemented climate policies are estimated to result in about 2.6°C of global warming by the end of this century,” Annika Ernest Högner of the Potsdam Institute for Climate Impact Research and one of the researchers who co-led the study, said in a statement.
"This analysis of tipping point risks adds further support to the conclusion that we are underestimating risks, and need to now recognize that the legally binding objective in the Paris Agreement of holding global warming to ‘well below 2°C’, in reality means limiting global warming to 1.5°C,” said study co-author and Potsdam Institute director Johan Rockström. “Due to insufficient emission reductions, we run an ever increasing risk of a period overshooting this temperature limit, which we need to minimize at all costs, to reduce dire impacts to people across the world.”
Here are some of the key findings and takeaways from this study:
Current emissions reduction pledges and policies are insufficient to minimize tipping risks. Heating up the planet by 2.6°C over preindustrial levels by the end of this century, as is projected under current climate policies, would be disastrous in terms of the risk of triggering irreversible tipping points in the climate system. “This underscores the importance of the Paris Agreement climate objective to hold warming to ‘well below 2°C’ even in case of a temporary overshoot above 1.5°C,” the study states.
Stepping up climate action this decade is absolutely critical. Realizing net-zero greenhouse gas emissions by 2100 at the latest can reduce tipping risks, and the sooner emissions are zeroed out the better. Large-scale deployment of carbon dioxide removal (CDR) might be a necessary part of the mitigation portfolio, but it is risky and unproven and various CDR approaches come with their own concerns and limitations. Minimizing reliance on CDR necessitates steep emissions reductions during this decade. “Our results underscore that stringent emission reductions in the current decade are critical for planetary stability,” the study’s abstract states.
Even the 1.5°C limit is not really “safe.” The study emphasizes that keeping temperature rise at or as close to 1.5°C as possible (current levels are around 1.2°C) is essential in order to stave off the highest tipping risks. But, the study also cautions that 1.5°C “is not ‘safe’ in terms of planetary stability.” As the researchers explain: “Our findings imply that stabilization of global temperatures at or around 1.5°C is insufficient to limit tipping risk in the long term. In order to effectively minimize this risk, our study suggests that temperature needs to return to below 1°C above pre-industrial level.”
This is truly a decisive decade for climate action. The choices we make over the next few years could have enormous implications for human civilization and the planet for generations or centuries. Despite some progress on boosting clean energy and starting to curb emissions, the reality is that our society is on track for a much more dangerous and destabilizing future as the effort to address the climate problem has not been commensurate with the scale of this planetary crisis. Climate scientists are terrified. The risk of triggering climate tipping points is increasing. In simple terms, climate tipping means that the planet is breaking. Earth’s life-support systems break down.
“We are currently on a pathway to lose basically everything,” Peter Kalmus, a climate scientist with NASA’s Jet Propulsion Lab, said last year at the March to End Fossil Fuels in New York City. “This is not something that we can just reverse. It’s not like cleaning up garbage in a park. However hot it gets, that’s how hot it’s gonna stay for generations.” He said the science is clear that fossil fuels must be phased out to avoid calamity.
“The scientists of the world have spoken. We have to stop expanding fossil fuels and ramp down fossil fuels as quickly as we can. It cannot be more clear,” Kalmus said. “I’ve got two kids in high school. I am terrified for their future. I am terrified for my own future right now.”
Urgent climate action is needed now more than ever, scientists tell us. As the researchers on the climate tipping risks study conclude: “Domestic policies to reduce emissions need to be adopted and implemented, not only pledged, and a more significant and urgent effort is needed to mitigate the risks associated with tipping elements.”