Projections of the Transient State-Dependency of Climate Feedbacks

TL;DR

This paper introduces a multivariate, spatially explicit framework to analyze how climate feedbacks change over time and under different emission scenarios, improving understanding of transient climate responses.

Contribution

It presents a novel framework that accounts for state-dependent feedbacks and their spatial variations, enhancing projections of future climate change beyond traditional methods.

Findings

Framework successfully dissects feedbacks over multiple time scales.

Enables projections for various emission scenarios using linear response theory.

Applied to CESM2, revealing insights into feedback dynamics.

Abstract

When the climate system is forced, e.g. by emission of greenhouse gases, it responds on multiple time scales. As temperatures rise, feedback processes might intensify or weaken. Current methods to analyze feedback strength, however, do not take such state dependency into account; they only consider changes in (global mean) temperature and assume all feedbacks are linearly related to that. This makes (transient) changes in feedback strengths almost intangible and generally leads to underestimation of future warming. Here, we present a multivariate (and spatially explicit) framework that facilitates dissection of climate feedbacks over time scales. Using this framework, information on the composition of projected (transient) future climates and feedback strengths can be obtained. Moreover, it can be used to make projections for many emission scenarios through linear response theory. The new framework is illustrated using the Community Earth System Model version 2 (CESM2).