A group of the world’s leading climate scientists have warned the globe is reaching a range of tipping points that could lead to rapid and irreversible changes to the Earth’s climate unless urgent action is taken on climate change.
The scientists, including co-author and emeritus professor at the Australian National University Will Steffen, warn dominoes of uncontrollable massive releases of carbon dioxide are dangerously close to tipping and could push the planet into a state that threatens human civilisation.
AAP Newsagency reports the group of seven leading scientists, in an article published in the leading scientific journal Nature, warn that the globe is nearing nine major tipping points.
These include coral die-offs in the Great Barrier Reef, the extensive loss of Arctic sea ice and ice sheets in Greenland and Antarctica, the thawing of permafrost, and the destruction of boreal forests in high-altitude areas and the Amazon rainforest, they say in the commentary for scientific journal Nature.
The scientists highlighted the fact that current national climate change pledges are insufficient to limit warming to safe levels, and that the world is likely heading to warming of at least three degrees Celius above pre-industrial levels.
“As soon as one or two climate dominoes are knocked over, they push Earth towards others,” said Professor Steffen, one of the authors.
“We fear that it may become impossible to stop the whole row of dominoes from tumbling over, forming a cascade that could threaten the existence of human civilisations.”
Professor Steffen said each of these tipping points could trigger massive and uncontrollable releases of carbon into the atmosphere from where it had previously been stored on Earth.
That, in turn, would accelerate the heating and further destabilisation of other ice sheets.
“The time to act decisively is now. Any more dithering is irresponsible, as the risks are increasing year by year,” said Professor Stefan Rahmstorf, head of Earth system analysis at Germany’s Potsdam Institute for Climate Impact Research, and one of the authors.
“But even once we pass a tipping point, and probably we have done so for the West Antarctic Ice Sheet, we will need to reduce emissions even more urgently, to slow down the unfolding effects and to avoid passing further tipping points.”
The tipping points were identified two decades ago and it was initially thought they would only be reached if the Earth heated by 5.0°C.
However, the two most recent United Nations Intergovernmental Panel on Climate Change (IPCC) special reports said they could, in fact, happen with warming of between 1.0°C and 2.0°C.
The scientists warned the worst-case scenario was a “hothouse Earth” that would be far less hospitable to humans.
An emergency response of rapid action to reduce emissions is needed to stop this “tipping cascade”, they say.
“All nations need to recognise the seriousness of the situation and go well beyond their Paris Agreement pledges to cut emissions,” Professor Steffen said.
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