Earth tipping points pose ‘unprecedented’ threat to humanity
PARIS—Humanity faces an “unprecedented” risk from tipping points that could unleash a domino effect of irreversible catastrophes across the planet, researchers warned Wednesday.
The most comprehensive assessment ever conducted of Earth’s invisible tripwires was released as leaders meet for UN climate talks in Dubai with 2023 set to smash all heat records.
While many of the 26 tipping points laid out in the report—such as melting ice sheets—are linked to global warming, other human activities like razing swathes of the Amazon rainforest could also push Earth’s ecosystems to the brink.
Five of these are showing signs of tipping—from melting ice sheets threatening catastrophic sea level rise, to mass die-off of tropical coral reefs—the report warned.
Some may have already begun to irrecoverably transform.
Mass hungerOnce the world crosses the threshold for just one tipping point, dealing with the immediate humanitarian disaster could distract attention away from stopping the others, creating a “vicious cycle” of mass hunger, displacement and conflict, the report warned.
Tim Lenton, an Earth system scientist at University of Exeter and lead author of the report, told AFP that these tipping points pose a “threat of a magnitude that is unprecedented for humanity.”
But it was not all bad news.
The report also highlighted a range of positive tipping points—such as electric vehicles, renewable energy and changing to plant-based diets—that have the potential to swiftly build momentum and tip things back the other way.
“Imagine leaning back on a chair to that balance point where a small nudge can make a big difference,” Lenton said.
“You could end up sprawled on your back on the floor—or if you’re lucky, back upright.”
Shrunken ice sheets
A key concern is if the melting West Antarctic and Greenland ice sheets collapse.
That could raise sea levels 2 meters by 2100, exposing nearly half a billion people to frequent coastal flooding, the report said.
The Greenland ice sheet has been shrinking at such a rate that it might already be too late.
“Is it past the tipping point or could it stop shrinking? No one’s quite sure,” Lenton said.
The other three tipping points most at risk are dying tropical coral reefs, melting permafrost and an ocean current called the North Atlantic subpolar gyre circulation.
Another ocean tipping point is the Atlantic Meridional Overturning Circulation (Amoc), a vast system that regulates the global transfer of heat from the tropics into the northern hemisphere.
The new report said it was plausible—though unlikely—that the Amoc would collapse this century. —AFP
