CMIP6 GCMs versus global surface temperatures: ECS discussion - Highlighted Article

From: Climate Etc.

By: Nicola Scafetta

Date: September 25, 2022

CMIP6 GCMs versus global surface temperatures: ECS discussion

Two publications examining the equilibrium climate sensitivity (ECS) have recently been published in Climate Dynamics:

Scafetta, N. (2022a). CMIP6 GCM ensemble members versus global surface temperatures.

Lewis, N. (2022). Objectively combining climate sensitivity evidence.

These two papers are significant because they take different but complimentary approaches and achieve the same result – ECS <3°C. Scafetta (2022a) extends and confirm Scafetta (2022b) previously published in GRL.

Lewis study was discussed in a previous post, let us here briefly present the main findings of Scafetta (2022).

The Coupled Model Intercomparison Project (phase 6) (CMIP6) global circulation (GCM) models project equilibrium climate sensitivity (ECS) values ranging from 1.8 to 5.7°C. To reduce this range, the 38 GCM were divided into low (1.5<ECS<3.0 °C), medium (3.0<ECS<4.5°C), and high (4.5<ECs<6.0°C) ECS subgroups and their accuracy and precision were evaluated in hindcasting the average global surface warming observed from 1980-1990 to 2011-2021. The study used global surface temperature records are ERA5-T2m, HadCRUT5, GISTEMP v4, NOAAGlobTemp v5, and the satellite-based lower troposphere global temperature UAH-MSU lt v6 record was added as well. (continue reading)

CMIP6 GCMs versus global surface temperatures: ECS discussion