Climate emergency: world 'may have crossed tipping points' [View all]

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https://www.theguardian.com/environment/2019/nov/27/climate-emergency-world-may-have-crossed-tipping-points

Climate emergency: world 'may have crossed tipping points’

Damian Carrington Environment editor

Wed 27 Nov 2019 18.00 GMT Last modified on Wed 27 Nov 2019 19.30 GMT

The world may already have crossed a series of climate tipping points, according to a stark warning from scientists. This risk is “an existential threat to civilisation”, they say, meaning “we are in a state of planetary emergency”.

Tipping points are reached when particular impacts of global heating become unstoppable, such as the runaway loss of ice sheets or forests. In the past, extreme heating of 5C was thought necessary to pass tipping points, but the latest evidence suggests this could happen between 1C and 2C.

The planet has already heated by 1C and the temperature is certain to rise further, due to past emissions and because greenhouse gas levels are still rising. The scientists further warn that one tipping point, such as the release of methane from thawing permafrost, may fuel others, leading to a cascade.

The researchers, writing in a commentary article in the journal Nature, acknowledge that the complex science of tipping points means great uncertainty remains. But they say the potential damage from the tipping points is so big and the time to act so short, that “to err on the side of danger is not a responsible option”. They call for urgent international action.
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The new article comes as the UN warns action is very far from stopping global temperature rise, with the world currently on track for 3C-4C. The commentary lists nine tipping points that may have been activated.
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