Sep 9, 2022 - Energy & Environment

Study: World at risk of triggering multiple climate "tipping points"

Meltwater lakes on the Greenland ice sheet in August 2022.
Meltwater lakes on the Greenland ice sheet in August 2022. Photo: Lukasz Larsson Warzecha/Getty Images

Even if countries meet the more aggressive goals of the Paris Climate Agreement, global warming could likely still trigger several climate “tipping points" that would drastically change life on Earth, according to a new study published in the journal Science on Thursday.

Why it matters: "Tipping points" refer to junctures in the climate system that, when crossed, can usher in irreversible changes. Tipping points include the near-complete melting of the West Antarctic Ice Sheet or the shutdown of the ocean current that includes the Gulf Stream.

  • The study indicates that even the Paris Agreement's goal of keeping global warming at 1.5°C is not enough to fully avoid some of the dangerous effects of climate change.

How it works: The researchers considered 16 of these tipping elements and determined that at current levels of global heating, the world "already lies within the lower end of five [climate tipping point] uncertainty ranges."

  • These include the massive sea-level rise from irreversible collapse of the Greenland and West Antarctic ice sheets, the degradation of biodiverse biomes like the Amazon rainforest or warm-water coral reefs, and greenhouse gas emissions thawing permafrost.
  • If the world meets the Paris Agreement's goal of keeping global warming to 1.5 degrees Celsius compared to pre-industrial levels, the researchers said four of these trigger events become likely and five more become possible.
  • More trigger events become likely and possible with each tenth of a degree of further warming past 1.5C, they said.

What they're saying: “The world is heading towards 2-3°C of global warming," Johan Rockström, co-author of the paper and director of the Potsdam Institute for Climate Impact Research, said in a statement.

  • "This sets Earth on course to cross multiple dangerous tipping points that will be disastrous for people across the world. To maintain liveable conditions on Earth, protect people from rising extremes, and enable stable societies, we must do everything possible to prevent crossing tipping points. Every tenth of a degree counts," Rockström added.

The big picture: The United Nations warned in 2021 that the Earth will likely warm by more than 2.7°C by the end of the 21st century unless countries further cut greenhouse gas emissions.

  • A UN-sponsored report released last year projected that global warming at the end of the century may range between about 1.3 to 5.7°C compared to pre-industrial levels.
  • It also determined that the world could hit the Paris Agreement's warming limit of 1.5°C between 2030 and 2035.
  • The planet has already warmed 1.1°C above pre-industrial levels.

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