02-21-2022, 02:00 PM
https://e360.yale.edu/features/as-climat...ints-looms
As Climate Change Worsens, A Cascade of Tipping Points Looms
BY FRED PEARCE, DECEMBER 5, 2019
New research warns that the earth may be approaching key tipping points, including the runaway loss of ice sheets, that could fundamentally disrupt the global climate system. A growing concern is a change in ocean circulation, which could alter climate patterns in a profound way.
Some of the most alarming science surrounding climate change is the discovery that it may not happen incrementally — as a steadily rising line on a graph — but in a series of lurches as various tipping points are passed. And now comes a new concern: These tipping points can form a cascade, with each one triggering others, creating an irreversible shift to a hotter world. A new study suggests that changes to ocean circulation could be the driver of such a cascade.
A group of researchers, led by Tim Lenton at Exeter University, England, first warned in a landmark paper 11 years ago about the risk of climate tipping points. Back then, they thought the dangers would only arise when global warming exceeded 5 degrees Celsius (9 degrees Fahrenheit) above pre-industrial levels. But last week, Lenton and six co-authors argued in the journal Nature that the risks are now much more likely and much more imminent. Some tipping points, they said, may already have been breached at the current 1 degree C of warming.
The new warning is much starker than the forecasts of the Intergovernmental Panel on Climate Change, which critics say has until now played down the risks of exceeding climate tipping points, in part because they are difficult to quantify.
The potential tipping points come in three forms: runaway loss of ice sheets that accelerate sea level rise; forests and other natural carbon stores such as permafrost releasing those stores into the atmosphere as carbon dioxide (CO2), accelerating warming; and the disabling of the ocean circulation system.
Researchers’ biggest fear is for the future of the ocean circulation system, which moves heat around the world and may dictate global climate. The researchers once considered these tipping points to be largely independent of each other. Now they warn that the world faces a "cascade" of abrupt shifts in the planet’s climate system, as global warming takes hold. "We might already have crossed the threshold for a cascade of inter-related tipping points," they wrote in Nature. This "could trigger a shift in the state of the Earth system as a whole," one of the authors, Will Steffen of the Australian National University in Canberra, told Yale Environment 360......
As Climate Change Worsens, A Cascade of Tipping Points Looms
BY FRED PEARCE, DECEMBER 5, 2019
New research warns that the earth may be approaching key tipping points, including the runaway loss of ice sheets, that could fundamentally disrupt the global climate system. A growing concern is a change in ocean circulation, which could alter climate patterns in a profound way.
Some of the most alarming science surrounding climate change is the discovery that it may not happen incrementally — as a steadily rising line on a graph — but in a series of lurches as various tipping points are passed. And now comes a new concern: These tipping points can form a cascade, with each one triggering others, creating an irreversible shift to a hotter world. A new study suggests that changes to ocean circulation could be the driver of such a cascade.
A group of researchers, led by Tim Lenton at Exeter University, England, first warned in a landmark paper 11 years ago about the risk of climate tipping points. Back then, they thought the dangers would only arise when global warming exceeded 5 degrees Celsius (9 degrees Fahrenheit) above pre-industrial levels. But last week, Lenton and six co-authors argued in the journal Nature that the risks are now much more likely and much more imminent. Some tipping points, they said, may already have been breached at the current 1 degree C of warming.
The new warning is much starker than the forecasts of the Intergovernmental Panel on Climate Change, which critics say has until now played down the risks of exceeding climate tipping points, in part because they are difficult to quantify.
The potential tipping points come in three forms: runaway loss of ice sheets that accelerate sea level rise; forests and other natural carbon stores such as permafrost releasing those stores into the atmosphere as carbon dioxide (CO2), accelerating warming; and the disabling of the ocean circulation system.
Researchers’ biggest fear is for the future of the ocean circulation system, which moves heat around the world and may dictate global climate. The researchers once considered these tipping points to be largely independent of each other. Now they warn that the world faces a "cascade" of abrupt shifts in the planet’s climate system, as global warming takes hold. "We might already have crossed the threshold for a cascade of inter-related tipping points," they wrote in Nature. This "could trigger a shift in the state of the Earth system as a whole," one of the authors, Will Steffen of the Australian National University in Canberra, told Yale Environment 360......