We may have already pushed our planet beyond several tipping points and towards a scenario where the Earth begins "self amplifying" global warming in a series of unstoppable destructive feedback loops, scientists calling for an worldwide emergency response have warned.
One of the serious issues of discussion at COP25, which started in Madrid on December 2, is the irreversible climate change that is in store in the near future.
In a recent commentary that appeared in Nature, titled "Climate tipping points-too risky to bet against", a group of scientists have warned the world community that "we have reached a position where more than half of the climate tipping points deciphered a decade back, are now active".
This amounts to an "existential threat to civilisation", which requires an "emergency response".
Evidence is mounting that these events are more likely and more interconnected than was previously thought, leading to a possible domino effect.
"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".
They say the increasing risk of a tipping cascade is strong evidence for declaring a planetary-wide climate emergency now. While we fail to deal with our emissions, the impact is still being felt and triggering irreversible processes.
The climate tipping points denote the critical points or threshold of the planet's complex climate system. Since 1970, 17 per cent of the Amazon has been destroyed.
"Tipping point risks are now much higher than earlier estimates", Professor Steffen said. But it could plausibly get far worse.
"Currently we are seeing much higher risk, and we are rapidly running out of time to respond".
The scientists are calling for the world to "act now" to put the brakes on in order to avoid runaway overheating.
The scientists are also calling for a greater understanding of how emissions increase the likelihood of causing tipping points to be reached.
As permafrost in the Arctic is already melting, the resultant emissions could take around 20 per cent (100 Gt CO2) off this budget - and that's not even accounting for the impact of the methane which would be released. "With global total Carbon dioxide emissions still at more than 40 Gt per year, the remaining budget could be all but erased already", the article says.
It will be extremely hard to exit the fossil fuel economy before 2050, but with the temperature already exceeding 1.1 degree Celsius of pre-industrial level, Earth is very likely to cross the 1.5 degree guardrail by 2040. "No amount of economic cost-benefit analysis is going to help us".
For several years they have been promoting the theory that the climate can shift suddenly as a result of a climate shift strengthening other changes.
The latest commentary said that nine out of those fifteen tipping elements are active, which means that the Earth's climatic condition is progressing in such a fashion that very soon the nine climate tipping points would be crossed. The authors conclude this alone defines an emergency.