Climate sensitivity in light of the latest energy imbalance evidence

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Excellent article on Judith Curry's website regarding climate sensitivity (ECS) derived from energy imbalance data.

Equilibrium climate sensitivity computed from the latest energy imbalance data


The Earth Energy Imbalance (EEI) is a key issue for estimating climate sensitivity.

If EEI is positive then the Earth’s climate system gains energy; if it’s negative the system loses energy, largely due to the energy flow into or out of the oceans.

A recent paper, Dewitte et al (2019), henceforth D19, derives changes in the EE I during the period 2000-2018, using data from the satellite CERES mission.

They shift the CERES values so that their average matches an EEI estimate from another study that is based on in-situ ocean heat content (OHC) data from ARGO buoys, and drift-correct them.

D19 concludes:

“At first sight it seems surprising that the EEI is decreasing during a period of continued greenhouse gas emission.”

Read More: https://judithcurry.com/2020/01/10/...-latest-energy-imbalance-evidence/#more-25636

 

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The derived ECS best estimate (based on an ERF of 3.8 W/m² when doubling the CO2 content of the atmosphere) is:

3.8 W/m² / 2.21 W/m²/K =1.72 K

Conclusion

I calculated the climate sensitivity in a temporary standstill period (or slightly decreasing) as it was detected in the observations of the EEI during 1999 to 2018. The ECS value of 1.72K as the best estimate is in excellent agreement with the value found in LC18, 1.66K using the then current C&W GMST dataset (see Tab.3 of this paper).

The published ECS-values of the CMIP6 models have a mean above 4 K (see this recent paper) that is higher by a factor of 2.4 than observed here. This growing discrepancy between observed values of ECS reduces the credibility of the high model estimates.