"The climate crisis has arrived and is accelerating faster than most scientists expected. It is more severe than anticipated, threatening natural ecosystems and the fate of humanity. Especially worrisome are potential irreversible climate tipping points and nature's reinforcing feedbacks (atmospheric, marine, and terrestrial) that could lead to a catastrophic 'hothouse Earth,' well beyond the control of humans. These climate chain reactions could cause significant disruptions to ecosystems, society, and economies, potentially making large areas of Earth uninhabitable" (9).
Ripple, William J., et al. "World Scientists' Warning of a Climate Emergency." BioScience, vol. 70, no. 1, Jan. 2020, pp. 8-12
"Even if anthropogenic GHG emissions start to decline soon, this does not rule out high future GHG concentrations or extreme climate change, particularly beyond 2100. There are feedbacks in the carbon cycle and potential tipping points that could generate high GHG concentrations that are often missing from models. Examples include Arctic permafrost thawing that releases methane and CO2, carbon loss due to intense droughts and fires in the Amazon, and the apparent slowing of dampening feedbacks such as natural carbon sink capacity. These are likely to not be proportional to warming, as is sometimes assumed. Instead, abrupt and/or irreversible changes may be triggered at a temperature threshold. Such changes are evident in Earth's geological record, and their impacts cascaded across the coupled climate–ecological–social system. Particularly worrying is a 'tipping cascade' in which multiple tipping elements interact in such a way that tipping one threshold increases the likelihood of tipping another. Temperature rise is crucially dependent on the overall dynamics of the Earth system, not just the anthropogenic emissions trajectory" (2).
Kemp, Luke, et al. "Climate Endgame: Exploring Catastrophic Climate Change Scenarios." Proceedings of the National Academy of Sciences of the United States of America, vol. 119, no. 34, Aug. 2022