Multiple climate ‘tipping points’ are likely to be triggered if global policies stay on their current course, scientists assessing the risk of triggering 16 different parts of the Earth system, ranging from the collapse of major ice sheets to the dieback of tropical coral reefs and vast forests, have warned.
Based on current policies and the resulting global warming, their most conservative estimate is a 62% risk of triggering these tipping points on average.
The study (led by the Universities of Exeter and Hamburg) has been keen to point out, however, that more sustainable pathways – with lower greenhouse gas emissions – significantly reduce the risk of tipping points.
The research has also found that carbon released by certain tipping points (Amazon rainforest dieback and permafrost thaw) is unlikely to cause enough warming to trigger other tipping points.
The good news of the study is that the power to prevent climate tipping points “is still very much in our hands” and that – according to the paper’s lead author, Jakob Deutloff “by moving towards a more sustainable future with lower emissions, the risk of triggering these tipping points is significantly reduced.”
“And it appears that breaching tipping points in the Amazon and the permafrost region should not necessarily trigger others,” he said.
A ‘tipping point’ occurs when a small change tips a system into a new state, causing significant and long-term transformation. The study assessed tipping point probabilities in five different scenarios, known as ‘shared socioeconomic pathways’ (SSPs).
Increasing numbers of Earth system components have been identified which could possibly exhibit tipping behaviour, with 15 candidates being shortlisted in the latest IPCC report. These Earth system components are referred to as ‘tipping elements’ and occur within the biosphere, cryosphere, and oceanic or atmospheric circulation.