Study: Four Major Climate Tipping Points Near Trigger | Nation / world

Even if the world somehow manages to limit future warming to the most stringent international temperature goal, four Earth-changing climate “tipping points” are still likely to be triggered with much more of a threat as the planet heats up more after that, according to a new study.

An international team of scientists has looked at 16 climate tipping points – when a side effect of warming is irreversible, self-sustaining and major – and calculated approximate temperature thresholds at which they trigger. None of these are considered likely at current temperatures, although a few are possible. But with just a few tenths of a degree more warming from now, at 1.5 degrees Celsius (2.7 degrees Fahrenheit) since pre-industrial times, four is within the likely range, according to a study published Thursday in the journal Science.

The study indicates that the slow but irreversible collapse of the Greenland and West Antarctic ice sheets, the more immediate loss of tropical coral reefs around the world, and the thawing of northern permafrost which is releasing massive amounts of gas to greenhouse gases trapped in now frozen land are four major tipping points that could be triggered at 1.5 degrees Celsius of warming, or three tenths of a degree (half a degree Fahrenheit) warmer than today. Current policies and actions put the Earth on a warming trajectory of around 2.7 degrees Celsius (4.9 degrees Fahrenheit) since pre-industrial times, according to some projections.

“Let’s hope we’re not right,” said study co-author Tim Lenton, an earth systems scientist at the University of Exeter in the UK. “Chances are that some of these tipping points are unavoidable. And therefore, it’s really important that we think more about how we are going to adapt to the consequences.”

Timing is a key issue for Tipping Points in two ways: when they trigger and when they cause damage. And in many cases, like ice cap collapses, they could be triggered soon, but their impacts, while unavoidable, take centuries to manifest, the scientists said. A few, like the loss of coral reefs, cause more damage in just a decade or two.

“It’s a future-generation problem,” said the study’s lead author, David Armstrong McKay, an Earth systems scientist at the University of Exeter. “This collapsing ice cap is kind of this thousand-year timescale, but it’s still bequeathing an entirely different planet to our descendants.”

The concept of tipping points has been around for more than a decade, but this study goes further by examining temperature thresholds to find out when they can be triggered and what impacts they would have on people and the Earth and over the past 15 years or so “the risk levels just keep going up,” Lenton said.

Lenton likes to think of tipping points as someone leaning on a folding chair.

“When you start to rock backwards, then you have a very simple sort of feedback on the forces of gravity acting to propel you backwards to SPLAT,” Lenton said.

Study co-author Johan Rockstrom, director of the Potsdam Institute for Climate Impact Research in Germany, compared it to someone lighting a fuse on a bomb “and then the fuse will burn. until the big bang and the big bang could be further in time”. line.”

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