Scientists increasingly concerned about thresholds beyond which recovery may become impossible

https://www.theguardian.com/environment/2021/jun/23/climate-change-dangerous-thresholds-un-report?mc_cid=40aabfb9b0&mc_eid=8f4760cc57

The Guardian

June 23, 2021

Climate scientists are increasingly concerned that global heating will trigger tipping points in Earth’s natural systems, which will lead to widespread and possibly irrevocable disaster, unless action is taken urgently.  The impacts are likely to be much closer than most people realise, a a draft report from the world’s leading climate scientists suggests, and will fundamentally reshape life in the coming decades even if greenhouse gas emissions are brought under some control.  Tipping points are triggered when temperatures reach a certain level, whereby one impact rapidly leads to a series of cascading events with vast repercussions. For instance, as rising temperatures lead to the melting of Arctic permafrost, the unfreezing soil releases methane, a powerful greenhouse gas that in turn causes more heating.  Other tipping points include the melting of polar ice sheets, which once under way may be almost impossible to reverse even if carbon emissions are rapidly reduced, and which would raise sea levels catastrophically over many decades, and the possibility of the Amazon rainforest switching suddenly to savannah, which scientists have said could come quickly and with relatively small temperature rises.