2017/10/16 by Patrik L. Pfister, Thomas F. Stocker · 1 citation
Earth and Planetary Sciences · Environmental Science · Mathematics · #Geology and Paleoclimatology Research #Climate variability and models #Marine and coastal ecosystems #Forcing (mathematics) #Climate sensitivity #Climatology #Extrapolation #Albedo (alchemy) #Climate model #General Circulation Model #Environmental science #Radiative forcing #Sea level #Sensitivity (control systems) #GCM transcription factors #Atmospheric sciences #Magnitude (astronomy) #Physics #Climate change #Geology #Mathematics #Oceanography #Statistics
paper · pdf · doi:10.1002/2017gl075457
openalex publication_date 2017/10/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Abstract Growing evidence from general circulation models (GCMs) indicates that the equilibrium climate sensitivity (ECS) depends on the magnitude of forcing, which is commonly referred to as state‐dependence. We present a comprehensive assessment of ECS state‐dependence in Earth system models of intermediate complexity (EMICs) by analyzing millennial simulations with sustained 2×CO 2 and 4×CO 2 forcings. We compare different extrapolation methods and show that ECS is smaller in the higher‐forcing scenario in 12 out of 15 EMICs, in contrast to the opposite behavior reported from GCMs. In one such EMIC, the Bern3D‐LPX model, this state‐dependence is mainly due to the weakening sea ice‐albedo feedback in the Southern Ocean, which depends on model configuration. Due to ocean‐mixing adjustments, state‐dependence is only detected hundreds of years after the abrupt forcing, highlighting the need for long model integrations. Adjustments to feedback parametrizations of EMICs may be necessary if GCM intercomparisons confirm an opposite state‐dependence.