More than half of the climate tipping points identified a decade ago are now ‘active’, posing a major threat to the existence of human civilizations, warn scientists.
Global warming is threatening the loss of the Amazon rainforest, the great ice sheets of Antarctica and Greenland, warm-water corals and five other climate tipping points.
What’s more, there is growing evidence that these events are more likely and more interconnected than was previously thought, leading to a possible domino effect, according to a recently published article in the journal Nature.
“A decade ago we identified a suite of potential tipping points in the Earth system, now we see evidence that over half of them have been activated,” said lead author Professor Tim Lenton, director of the Global Systems Institute at the University of Exeter.
“The growing threat of rapid, irreversible changes means it is no longer responsible to wait and see. The situation is urgent and we need an emergency response.”
Co-author Johan Rockström, director of the Potsdam Institute for Climate Impact Research, explained that scientists underestimated the risks of such irreversible changes, where the planet self-amplifies global warming. “This is what we now start seeing, already at 1°C global warming,” Rockström said.
“Scientifically, this provides strong evidence for declaring a state of planetary emergency, to unleash world action that accelerates the path towards a world that can continue evolving on a stable planet.”
For example, the collapse of major ice sheets on Greenland, West Antarctica and part of East Antarctica would result in around 10 meters of irreversible sea-level rise. Reducing emissions could slow this process to allow more time for low-lying populations to move, but it wouldn’t reverse it.
Despite most countries having signed the Paris Agreement, pledging to keep global warming well below 2°C, current national emissions pledges – even if they are met – would lead to 3°C of warming.
“If damaging tipping cascades can occur and a global tipping cannot be ruled out, then this is an existential threat to civilization.”
Photo credit: Ian Britton via Flickr