Understanding Climate Feedbacks and Sensitivity Using Observations of Earth's Energy Budget.

Wenying Su,Seiji Kato,Norman G. Loeb

doi:10.1007/s40641-016-0047-5

Abstract

While climate models and observations generally agree that climate feedbacks collectively amplify the surface temperature response to radiative forcing, the strength of the feedback estimates varies greatly, resulting in appreciable uncertainty in equilibrium climate sensitivity. Because climate feedbacks respond differently to different spatial variations in temperature, short-term observational records have thus far only provided a weak constraint for climate feedbacks operating under global warming. Further complicating matters is the likelihood of considerable time variation in the effective global climate feedback parameter under transient warming. There is a need to continue to revisit the underlying assumptions used in the traditional forcing-feedback framework, with an emphasis on how climate models and observations can best be utilized to reduce the uncertainties. Model simulations can also guide observational requirements and provide insight on how the observational record can most effectively be analyzed in order to make progress in this critical area of climate research.

Highlights

Climate is determined by the amount and distribution of incoming solar radiation absorbed by Earth
Using 10 years of Clouds and the Earth’s Radiant Energy System (CERES) top of atmosphere (TOA) radiation and surface temperature measurements, Dessler [25] and Dessler [26] applied the methodology of Soden et al [27] and Shell et al [28] to show that climate feedbacks from short-term observations and global climate model control runs are generally consistent, there are notable differences in the regional pattern of cloud feedback
While observationally based estimates suggest that climate feedbacks collectively enhance the temperature response to a forcing, the magnitudes of the climate feedback parameter estimates vary greatly

Summary

Introduction

Climate is determined by the amount and distribution of incoming solar radiation absorbed by Earth. Following Gregory et al [6, 7], Forster and Gregory [8] use a linearized version of the Earth’s global energy balance in which TOA net downward radiative flux is equated with the difference between TOA radiative forcing and the surface temperature change multiplied by the climate feedback parameter.

Results

Conclusion