Climate tipping points are conditions beyond which changes in a part of the climate system become self-perpetuating. Global warming rates have put the Earth at risk of causing 6 dangerous climate emergency events soon. Crossing these thresholds would mean disrupting the Earth’s systems, triggering the collapse of ice sheets and loss of coral reefs.
Research, based on data published since 2008, found that the risks increase with each tenth of a degree of warming. Even under an optimistic scenario, if current global climate targets are achieved, the world will see average warming of 1.8 degrees Celsius. If these “tipping points” are ‘tipped over, it would affect oceans, weather and chemical processes, which would be “irreversible”, according to the UN.
While in 2008 it was thought that the tipping points would only be crossed if global average temperatures increased to more than 5 degrees Celsius, there has now been increasing evidence that these thresholds may be crossed much earlier.
The six tipping points likely to be crossed are:
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Greenland Ice Sheet collapse
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West Antarctic Ice Sheet collapse
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The collapse of ocean circulation in the polar region of the North Atlantic
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Coral reef die off in the lower latitudes
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Sudden thawing of permafrost in northern regions
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Abrupt sea ice loss in the Barents Sea
The lead author of the research, David Armstrong McKay from Stockholm Resilience Centre, University of Exeter and the Earth Commission, said some destabilisation which precedes a system breakdown is already starting to be seen in the polar regions.
Greenland and Antarctica are currently losing ice six times faster than 30 years ago, and Greenland’s ice sheet has been shrinking continuously for the last 25 years due to climate change, according to the UN.
Even though some other tipping points such as dieback in the Amazon Rainforest aren’t expected to be triggered unless global temperatures rise by 3.5 degrees Celsius, all of these systems are connected.
A 2021 study with three million computer simulations of a climate model further showed that nearly one-third of those simulations would result in domino (or “cascading”) effects even if temperature increases were limited to 2 degrees Celsius – the upper limit set by the 2015 Paris Agreement. While there is great uncertainty as to how these effects may unfold, the cascading tipping points represent “an existential threat to civilisation”.
The 10 m of sea level rise from the combined melt of Greenland and West Antarctica would require moving many cities inland. A collapse of the Atlantic Overturning Circulation would alter Europe radically, and lead to a metre of sea level rise in the North Atlantic. These impacts could happen simultaneously in the case of cascading tipping points.
The intervention time left to prevent tipping could already have shrunk to zero, and the reaction time to achieve net zero emissions is 30 years at best. Therefore, we might already have lost control of whether tipping happens. A saving grace is that the rate at which damage accumulates from tipping — and hence the risk posed — could still be under our control to some extent.
The stability and resilience of our planet is in peril. International action, including on an organizational and individual level, and not just words, must reflect this.
