Climate crisis, becoming a real threat to human civilization, needs to be tackled on exigent basis. We are moving speedily toward a “global tipping point” if the climate crisis continues on its current path, scientists have warned.
The group of researchers, who published a commentary in the journal Nature say there is growing evidence to suggest that irreversible changes to the Earth’s environmental systems are already taking place, and that we are now in a “state of planetary emergency.”
A global tipping point is a threshold when the planet’s systems go beyond the point of no return — such as the loss of the Amazon rainforest, accelerated melting of ice sheets, and thawing of permafrost — the authors of the commentary say.
Such a collapse could lead to “hothouse” conditions that would make some areas on Earth uninhabitable.
“We argue that the intervention time left to prevent tipping could already have shrunk towards zero, whereas the reaction time to achieve net zero emissions is 30 years at best,” the authors said.
Led by Timothy Lenton, professor of climate change and Earth system science at the University of Exeter, in southwest England, the team identified nine areas where they say tipping points are already underway.
Those include widespread destruction of the Amazon, reduction of Arctic sea ice, large-scale coral reef die-offs, melting of the Greenland and West Antarctic ice sheets, thawing of permafrost, destabilizing of boreal forests — which contain vast numbers of trees that grow in freezing northern climes — and a slowdown of ocean circulation.
The team claims that these events are interconnected and change in one will impact another, causing a worsening “cascade” of crises.
For example, the Arctic is warming at least twice as quickly as the global average. Melting Arctic sea ice is driving warming further because less heat is reflected off the planet.
That regional warming is leading to an increased thawing of Arctic permafrost, soil that stays frozen throughout the year, which is releasing carbon dioxide and methane into the atmosphere. The warming has triggered large-scale insect disturbances and fires in North American boreal forests “potentially turning some regions from a carbon sink to a carbon source,” the team said.
One report from 2018 — of which Lenton was part of — suggested that a domino effect will kick in if global temperatures rise more than 2 degrees Celsius above pre-industrial levels.
The model highlighted the consequences of how the interactions between a variety of climate change factors, such as the loss or weakening of carbon sinks, forest dieback, ice retreat and increased bacteria respiration, could combine to form a feedback loop which accelerates climate change.
The authors acknowledge that there are limits to their understanding of climate tipping, and further investigation is needed. But they say the possible impact could be so huge and “irreversible” that “to err on the side of danger is not a responsible option.”
In other words, not acting is “too risky to bet against” in their view.
Hope is not lost, however. Researchers say that mitigating greenhouse gas emissions could still slow down the accumulation of these climate impacts.
What is needed, they say, is urgent international action to cut emissions, slow sea level rise, and to keep warming to 1.5 C.
“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,” they said.
“The stability and resilience of our planet is in peril. International action — not just words — must reflect this.”