At the most aggregate level, there is a long-standing literature exploring economically optimal global trade-offs between climate risks and mitigation , as well as global stochastic analysis exploring global risk hedging for a small number of uncertainties . Recent work has found optimal global emissions and climate pathways to be highly sensitive to uncertainties and plausible alternative assumptions, with uncertainties throughout the causal chain from society to emissions to climate to climate damages shown to imply a wide range of different possible economically optimal pathways . Among other things, this work identifies assumptions consistent with limiting warming to different temperature levels. For example, the combination of potential annual climate damages of 15% of global GDP at 4℃ of warming and a less sensitive climate system were consistent with an economically efficient global pathway limiting warming to 2ºC. In addition, this work highlights the importance of characterising and managing uncertainties. These types of global aggregate analyses inform discussions regarding long-run global pathways and goals but are not designed to inform local planning.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report