World might have crossed climate change tipping point

By Charlotte King


It’s come to light that some fear more than half of climate tipping points identified approximately ten years ago have become “active”, according to a leading group of scientists from the University of Exeter.

The group of scientists are now calling for “urgent action” to drastically reduce the volume of greenhouse gases being emitted in order to prevent us from going past more key tipping points. It’s believed that a “cascade of changes” have occurred, sparked by steadily rising temperatures which researchers fear could threaten the existence of human civilisations.

Reaching a tipping point happens when the impacts of planetary warming become uncontrollable and ultimately irreversible. Previously, it was thought that global warming of 5C was needed to pass tipping points, but that has not been the case. Professor Tim Lenton, Director of the Global Systems Institute at the University of Exeter, an institute which specialises in applying Earth science to generate more sustainable practices, and lead author of the report, said: “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. “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.”

It is now thought that there are nine active tipping points worldwide, including Arctic sea ice; Greenland ice sheet; the Amazon rainforest, and warm-water corals. The report states that if major ice sheets in Greenland, West and parts of East Antarctica were to collapse, the world would experience approximately ten metres of sea-level rise which would prove irreversible. Moreover, if the tipping points in rainforests, permafrost and boreal forests are crossed, there would be an inevitable  in additional greenhouse gases into the atmosphere, amplifying the effects of global warming.

Johan Rockström, co-author of the paper and Director of the Potsdam Institute for Climate Impact Research, which specialises in addressing scientific questions in the field of global change, also said: “It is not only human pressures on earth that continue rising to unprecedented levels. “It is also that as science advances, we must admit that we have underestimated the risks of unleashing irreversible changes, where the planet self-amplifies global warming. He continued, “Scientifically, this provide2s 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.”

Ultimately, scientists claim these tipping points have been reached far earlier than previously expected. The report states that we are already at 1C global warming, and even if all countries signed up to the Paris Climate Agreement stuck to their emissions goals, the world will still see “at least” 3C of planetary warming by the end of this century, which would have both environmental and socioeconomic consequences. Lenton also fears that “we might have already crossed the threshold for a cascade of inter-related tipping points [but] the rate at which they progress, and therefore the risk they pose, can be reduced by cutting out emissions.”

However, in the report, the researchers state that the science surrounding tipping points is complex, meaning there is still a lot of uncertainty with regards to the potential damage of passing tipping points. But, they stress that “to err on the side of danger is not a responsible option”.

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