The Earth’s Energy Budget, Climate Feedbacks and Climate Sensitivity

Abstract

This work extracts the chapter seven of the IPCC AR6 working group I on the Earth’s energy budget, climate feedback, and climate sensitivity, and gives a concise summary on the new findings and conclusions on the topic. AR6 suggests that the effective radiative forcing (ERF) from anthropogenic activity over the industrial era is 2.72 [1.96-3.48] W/m2. Changes in well-mixed greenhouse gases and aerosols contribute to the total anthropogenic ERF with 3.32 [3.03-3.61] W/m2 and -1.1 [-1.7-0.4] W/m2, respectively. The net climate feedback parameter is assessed to be -1.16 [-1.81-0.51] W/(m2∙℃), and clouds remain the largest contribution to overall uncertainty in climate feedbacks. Equilibrium climate sensitivity (ECS) and transient climate response (TCR) are effective measures that can be used to assess the response of global mean surface air temperature to forcing factors. The best estimates of ECS and TCR are 3.0 [2.0-5.0]℃ and 1.8 [1.2-2.4]℃, respectively.