Risk of multiple interacting tipping points should encourage rapid CO2 emission reduction
Nature Climate Change
Nature Publishing Group
This is the author accepted manuscript. The final version is available from Nature Publishing Group via the DOI in this record.
Reason for embargo
Evidence suggests that several elements of the climate system could be tipped into a different state by global warming, causing irreversible economic damages. To address their policy implications, we incorporated five interacting climate tipping points into a stochastic-dynamic integrated assessment model, calibrating their likelihoods and interactions on results from an existing expert elicitation. Here we show that combining realistic assumptions about policymaker’s preferences under uncertainty, with the prospect of multiple future interacting climate tipping points, increases the present social cost of carbon (SCC) in the model nearly 8-fold from $15/tCO2 to $116/tCO2. Furthermore, passing some tipping points increases the likelihood of other tipping points occurring to such an extent that it abruptly increases the social cost of carbon. The corresponding optimal policy involves an immediate, massive effort to control CO2 emissions, which are stopped by mid-century, leading to climate stabilization at <1.5 °C warming above pre-industrial levels.