From Watts Up With That?

Essay by Eric Worrall

What does it take to properly cross one of these tipping points?

Overshoot: The World Is Hitting Point of No Return on Climate

With warming set to pass the critical 1.5-degree limit, scientists are warning that the world is on course to trigger tipping points that would lead to cascading consequences — from the melting of ice sheets to the death of the Amazon rainforest — that could not be reversed.

BY FRED PEARCE • JANUARY 28, 2026

The world is poised to overshoot the goal of limiting average global warming to 1.5 degrees Celsius, as for the first time, a three-year period, ending in 2025, has breached the threshold. And climate scientists are predicting devastating consequences, just as the world’s governments appear to have lost their appetite for tackling the emissions that are causing the warming. 

…

“We are rapidly approaching multiple Earth system tipping points that could transform our world with devastating consequences for people and nature,” says British global-systems researcher Tim Lenton, of the University of Exeter. If he and other scientists are right, then hopes currently being expressed of a temperature reset by reducing emissions after overshoot may be fanciful. Before we know it, there may be no way back.

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A three-year breach of 1.5 degrees does not mean we have broken the Paris limit, which is framed as a long-term average. Conventionally, scientists measure this over 20 years, to smooth out year-on-year aberrations caused by natural cycles such as the El Niño oscillation. Using this method, it will be several more years before researchers can say for certain if warming has reached 1.5 degrees. But according to two studies published last year, the world has likely already surpassed this critical threshold. 

Without an abrupt change of course, the warming will only accelerate. James Hansen, the Columbia University climatologist who first put climate change on the world’s front pages during testimony to Senate hearings in 1988, believes we could hit 2 degrees C as soon as 2045, a forecast based on several climate models under a high-emissions scenario. 

…Read more: https://e360.yale.edu/features/1.5-degrees-tipping-points

I have a theory about 1.5C. Climate scientists appeared to be building up to a big dramatic tipping point crossed media frenzy, then the world spoiled the media campaign by abruptly jumping above their doomsday limit, likely due to the Hunga Tonga eruption.

Hunga Tonga volcano: impact on record warming

Hunga Tonga was an unusual eruption, because rather than blasting vast quantities of sulphur into the atmosphere, which would have temporarily cooled the planet, it blasted vast quantities of water vapour into the atmosphere, which has a strong warming effect.

The impact on climate scientists of blowing up their 1.5C limit was just as devastating as the impact of the eruption on Hunga Tonga on anyone nearby. I mean, here they were building up to a carefully orchestrated 1.5C climate disaster, then nature goes and spoils everything by shoving the world past their doomsday limit before they were ready.

The distinct lack of any noticeable doom hasn’t helped matters.

Now climate scientists seem to be flailing about, trying to figure out how to put their climate doomsday campaign back on track.

For a while there was an attempt to quietly memory hole the 1.5C limit, by pushing the new 2C limit, as if 1.5C wasn’t that important anyway.

Passing 1.5C Global Warming is Now an “Opportunity”

But the attempt to switch to 2.0C didn’t really gain traction. Everyone knew the 1.5C red line, so it was just too embarrassing to backflip the narrative by claiming it never really mattered.

So, climate scientists were forced to try to rescue their 1.5C narrative.

Passing a red line, that has some psychological impact. But passing a deadline then waiting years for anything interesting to happen, that’s just boring.

Obviously, these struggling climate scientists need our help to try to think up a new way to engage the public, to get past the embarrassment of their flopped 1.5C red line. What do you suggest?

Update (EW): Added “on anyone nearby” to clarify what I meant by the impact of the eruption of Hunga Tonga.