Climate tipping points will not be the point of no return

A new study suggests that the catastrophic consequences of climate “tipping points” could still be prevented if global warming is swiftly reversed. The experts report that tipping points will not necessarily be permanent, depending on how quickly we act. 

Once a certain threshold of warming is reached, tipping points in the climate system will trigger abrupt changes such as the loss of major ice sheets and large carbon stores like forests.

In previous studies, scientists have warned that a cascading series of climate events could push the Earth into a hothouse state that is characterized by food and water shortages, the displacement of hundreds of millions of people due to sea level rise, and unsuitable living conditions.

But while it is assumed that crossing the threshold of climate tipping points would be the point of no return, the new study concludes that thresholds could be “temporarily exceeded” without prompting permanent shifts.

According to the researchers, the time available to act would depend on the level of global warming and the timescale involved in each tipping point.

Study lead author Dr. Paul Ritchie is an expert in the Global Systems Institute and the Department of Mathematics at the University of Exeter.

“The more extreme the warming, the less time we would have to prevent tipping points,” said Dr. Ritchie. “This is especially true for fast-onset tipping points like Amazon forest dieback and disruption to monsoons, where irreversible change could take place in a matter of decades.”

“Slow-onset tipping points take place over a timescale of many centuries and – depending on the level of warming – this would give us more time to act.”

Study co-author Joe Clarke said that fortunately, the events that are predicted to occur first are slow-onset tipping points. “This may give us a lifeline to avoid dangerous climate change.”

Major tipping points, like the shrinking Greenland ice sheet, are the main focus of the Paris Agreement. For this treaty, 197 nations have made commitments to work toward a common goal of limiting global warming to 1.5 degrees Celsius above pre-industrial levels. 

However, the current rates of climate warming make it almost inevitable that Earth’s temperature will exceed the targeted, noted Professor Peter Cox.

“It is widely assumed that this means we are now committed to suffering these tipping events,” said Dr. Ritchie.

“We show that this conventional wisdom may be flawed, especially for slow-onset tipping elements such as a collapse of the Atlantic Meridional Overturning Circulation or the melting of ice sheets.”

Dr. Chris Huntingford said that, ideally, we will not cross tipping point thresholds, but this gives hope we may be able to pull back from danger if needed.

The study is published in the journal Nature.

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By Chrissy Sexton, Earth.com Staff Writer