Key points are not available for this paper at this time.
Abstract. Observing climate feedbacks to long term global warming, crucial climate regulators, is not feasible within the observational record. However, linking them to top-of-the-atmosphere flux variations in response to surface temperature fluctuations (internal variability feedbacks) is a viable approach. Here, we explore the use of this method of relating internal variability to forced climate feedbacks in models and applying the resulting relationship to observations to constrain forced climate feedbacks. Our findings reveal strong longwave and shortwave feedback relationships in models during the 14-year overlap with the CERES observational record. Yet, due to the weaker relationship between internal variability and forced climate longwave feedbacks, the net feedback relationship remains weak, even over longer periods extending beyond the CERES record. However, after about half a century, this relationship strengthens primarily due to a reinforcement of the relationship between internal variability and forced climate shortwave feedbacks. We therefore explore merging the satellite records with reanalysis to establish an extended data record. The resulting constraint suggests a stronger negative forced climate net feedback than the model´s distribution and an equilibrium climate sensitivity of about 2.5 K (2.14 K to 3.07 K, 5–95 % confidence intervals). Nevertheless, for example biogeochemical climate feedbacks, inactive on short time scales, and also not represented in most models, may lead to climate sensitivity being underestimated by this method. Also, continuous satellite observations until at least the mid-2030s are necessary for using purely observed estimate of the net internal variability feedback in constraining net forced climate feedback and, consequently, climate sensitivity.
Uribe et al. (Wed,) studied this question.