Earth may be approaching irreversible climate tipping points

A new analysis suggests parts of Earth’s climate system may be approaching dangerous tipping points sooner than scientists once expected.

The concern is that once certain thresholds are crossed, powerful feedback loops could accelerate warming and sea-level-rise, making the resulting changes extremely difficult to reverse.

The study brings together evidence on climate feedbacks and 16 major “tipping elements,” including ice sheets, forests, ocean currents, and frozen soils.

Led by Oregon State University scientist William Ripple, the international research team warns that the planet may be drifting away from the stable climate conditions that allowed modern societies to develop, raising the risk of faster and more abrupt climate shifts.

Climate stability may be ending

The researchers start from a simple idea: Earth has not always had a calm, predictable climate. Compared with much of the last million years, the relatively steady period we’ve lived in has been a historical exception.

“After a million years of oscillating between ice ages separated by warmer periods, the Earth’s climate stabilized more than 11,000 years ago, enabling agriculture and complex societies,” Ripple said.

“We’re now moving away from that stability and could be entering a period of unprecedented climate change.”

That matters because tipping points aren’t just about gradual change. They’re about systems snapping into a different state. Once a shift happens, it can make other shifts more likely, like dominoes in a tightly connected world.

What are tipping elements?

In this study, tipping elements are major parts of the Earth system that can lose stability if warming passes critical temperature thresholds. The list includes ice, oceans, forests, and frozen soils.

Some of the key tipping elements are the Greenland and Antarctic ice sheets, mountain glaciers, and sea ice.

Others include boreal forests and permafrost, the Amazon rainforest, and the Atlantic Meridional Overturning Circulation, (AMOC), a major system of ocean currents that strongly influences global climate.

The researchers are concerned that sharp shifts in one place could trigger a cascade of changes elsewhere.

That kind of chain reaction could steer the planet toward extreme warming and rising seas that would be difficult to undo on human timescales, even with major emissions cuts.

The temperature milestone warning

The analysis also points to a worrying milestone. Nearly 10 years after the Paris Agreement set a goal of limiting long-term warming to 1.5°C above preindustrial levels, global temperature increases exceeded 1.5°C for 12 straight months.

That stretch also overlapped with extreme, deadly, and expensive climate disasters, including wildfires and floods.

The authors argue that the year-long breach is not something to shrug off as a short-lived anomaly, because it could indicate the long-term average is already hovering near that level.

Temperature limit exceedance is typically evaluated using 20-year averages, but climate model simulations suggest that the recent 12-month breach indicates the long-term average warming is already at or near 1.5 degrees.

“It’s likely that global temperatures are as warm as, or warmer than, at any point in the last 125,000 years and that climate change is advancing faster than many scientists predicted,” said study co-author Christopher Wolf, a scientist with Terrestrial Ecosystems Research Associates (TERA).

The researchers also point to greenhouse gases as another red flag. They say carbon dioxide levels are likely the highest in at least 2 million years.

With atmospheric CO2 above 420 parts per million, the concentration is about 50 percent higher than it was before the Industrial Revolution.

Climate feedbacks speed warming

One reason that tipping points are so frightening is that climate change can feed on itself.

The study describes how warming triggers responses in ice, forests, soils, and oceans that can circle back and intensify the original warming. These are climate feedback loops.

“Amplifying feedbacks increase the risks of accelerated warming,” Ripple said. “For example, melting ice and snow, permafrost thaw, forest dieback, and soil-carbon loss can all magnify warming – and in turn affect the climate system’s sensitivity to greenhouse gases.”

That “amplifying” part is key. Melting ice reduces the planet’s reflectivity, so it absorbs more heat. Thawing permafrost can release greenhouse gases. Forest dieback can weaken a major natural carbon sink.

Once these processes are underway, they can push the system toward even more warming without any extra emissions added in that moment.

One tipping point can trigger another

The team sketched out a scenario that links Greenland, the AMOC, and the Amazon. For example, as the Greenland ice sheet melts, it could further weaken the AMOC, which in turn could trigger parts of the Amazon to tip from rainforest to savanna.

“The AMOC is already showing signs of weakening, and this could increase the risk of Amazon dieback, with major negative impacts on carbon storage and biodiversity,” Ripple said.

“Carbon released by an Amazon dieback would further amplify global warming and interact with other feedback loops. We need to act quickly on our rapidly dwindling opportunities to prevent dangerous and unmanageable climate outcomes.”

The research also suggests tipping may already be starting in some places. Greenland and West Antarctic ice sheets may be tipping, and boreal permafrost, mountain glaciers, and the Amazon appear close to the edge.

Urgent climate actions needed

The team argues that uncertainty is not comforting here. If anything, it’s a reason to act with more caution. If thresholds are unclear, you don’t want to discover them by crossing them.

“Existing climate mitigation approaches, including scaling up renewable energy and protecting carbon-storing ecosystems, are critical to limit the increase in global temperatures,” Ripple said.

They also call for climate resilience to be baked into government policy, alongside a socially just phaseout of fossil fuels. Beyond that, they argue for more serious risk planning, including coordinated global monitoring of tipping points.

“Uncertain tipping thresholds underscore the importance of precaution – crossing even some of those thresholds could commit the planet to a hothouse trajectory with long-lasting and possibly irreversible consequences,” Wolf said.

Researchers point out that policymakers and the public remain largely unaware of the risks posed by what could become a point-of-no-return transition.

Avoiding a “hothouse” climate trajectory would be far more achievable for Earth than trying to reverse course once the transition is underway.

The study is published in the journal One Earth.

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