Transparency crucial to Paris climate scenarios—Response

Abstract

King et al. raise important issues, several of which pertain to the broader policy discourse surrounding international climate negotiations and countries’ cli-mate pledges rather than the modeling conducted in our Policy Forum. We agree with King et al. that the updated Paris Agreement pledges could paint an overly optimistic picture of the future, especially if their success depends on postponing deeper reductions until after 2030. To illustrate a less-optimistic future, our Policy Forum includes scenarios showing what would happen if countries continued to implement current policies alone. Importantly, the “Current policy” scenarios in the Policy Forum result in less than a 10% chance of limiting global warming to below 2°C this century, whereas the “Updated pledges” scenarios result in at least a 33% chance of achieving the same temperature goal. Additional policy measures could help bridge emission gaps between current policies, updated pledges, and the global emission levels needed to cost-effectively achieve the Paris Agreement’s climate goals (1).