Earth barrelling towards multiple ‘irreversible’ climate tipping points under current warming rate, study says

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Earth barrelling towards multiple ‘irreversible’ climate tipping points under current warming rate, study says

The Earth’s current warming rate due to greenhouse gas emissions could lead to the planet crossing several “irreversible” climate tipping points by the 2030s, a new study warned.

The research, published on Friday in the journal Science, calls for limiting additional warming “as much as possible” as risks of irreversible damage to the planet increase with each tenth of a degree of further warming.

“Our new work provides compelling evidence that the world must radically accelerate decarbonising the economy to limit the risk of crossing climate tipping points,” Tim Lenton, director of the Global Systems Institute at the University of Exeter, said in a statement.

Climate tipping points, researchers say, are threshold conditions, which if hit, will cause climate change damage that is irreversible.

“These changes may lead to abrupt, irreversible, and dangerous impacts with serious implications for humanity,” scientists warned in the study.

Scientists conducted a comprehensive review of over 200 papers published since 2008, and developed an updated assessment of the most important climate tipping points, including temperature thresholds, time scales and impacts.

These include the Greenland and West Antarctic ice sheets, widespread abrupt permafrost thaw, and massive die-off of tropical coral reefs.

The research found that 16 major systems involved in regulating the planet’s climate – so-called “tipping elements” – “have the potential” to cross tipping points where their changes can become self-sustaining and likely irreversible.

It suggested that even if the global temperature stopped rising, once the ice sheet, ocean, or rainforest passed a tipping point, it would carry on changing to a new state.

Five of the 16 known tipping points may be triggered even at today’s temperatures, scientists say.

They say four of these move from “possible events” to “likely” at a global warming scenario of 1.5C above pre-industrial levels and five more become possible around this level of heating.

“We can see signs of destabilisation already in parts of the West Antarctic and Greenland ice sheets, in permafrost regions, the Amazon rainforest, and potentially the Atlantic overturning circulation as well,” study lead author David Armstrong McKay from the University of Exeter says. “The world is already at risk of some tipping points. As global temperatures rise further, more tipping points become possible.”

Limiting warming to well below 2C and preferably 1.5C is not enough to fully avoid dangerous climate change, scientists warn.

However, they say the chance of crossing tipping points can be reduced significantly by rapidly cutting greenhouse gas emissions, starting immediately.

The study estimates that global greenhouse gas emissions must be cut by half by 2030, reaching net-zero by 2050, in order to have a 50 per cent chance of achieving 1.5C and thus limiting tipping point risks.

“The world is heading towards 2-3C of global warming. This sets Earth on course to cross multiple dangerous tipping points that will be disastrous for people across the world,” Johan Rockström, director of the Potsdam Institute for Climate Impact Research, said.

“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,” Dr Rockström added.

Scientists warn that crossing these limits may generate cascading effects that increase the likelihood of crossing other such tipping points.

“Currently the world is heading toward 2 to 3C of global warming; at best, if all net-zero pledges and nationally determined contributions are implemented it could reach just below 2C. This would lower tipping point risks somewhat but would still be dangerous as it could trigger multiple climate tipping points,” they concluded.