Datasets used in Bacmeister et al, JAMES (2020). " CO2 increase experiments ..."

Datasets used in the creation of original figures of Bacmeister et al. JAMES (2020). CO2 increase experiments using the Community Earth System Model (CESM): Relationship to climate sensitivity and comparison of CESM1 to CESM2.

We examine the response of the Community Earth System Model versions 1 and 2 (CESM1 and CESM2) to abrupt quadrupling of atmospheric CO2 concentrations (4xCO2) and to 1% annually increasing CO2 concentrations (1%CO2). Different estimates of equilibrium climate sensitivity (ECS) for CESM1 and CESM2 are presented. All estimates show that the sensitivity of CESM2 has increased by 1.5K or more over that of CESM1. At the same time the transient climate response (TCR) of CESM1 and CESM2 derived from 1%CO2 experiments has not changed significantly - 2.1K in CESM1 and 2.0K in CESM2. Increased initial forcing as well as stronger shortwave radiation feedbacks are responsible for the increase in ECS seen in CESM2. A decomposition of regional radiation feedbacks and their contribution to global feedbacks shows that the Southern Ocean plays a key role in the overall behavior of 4xCO2 experiments, accounting for about 50% of the total shortwave feedback in both CESM1 and CESM2. The Southern Ocean is also responsible for around half of the increase in shortwave feedback between CESM1 and CESM2, with a comparable contribution arising over tropical ocean. Experiments using a thermodynamic slab-ocean model (SOM) yield estimates of ECS that are in remarkable agreement with those from fully-coupled earth system model (ESM) experiments for the same level of CO2 increase. Finally, we show that the similarity of TCR in CESM1 and CESM2 masks significant regional differences in warming that occur in the 1%CO2 experiments for each model.

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Questions? Email Resource Support Contact:

  • Cecile Hannay
    UCAR/NCAR - Climate and Global Dynamics Laboratory


Resource Type dataset
Temporal Range Begin N/A
Temporal Range End N/A
Temporal Resolution N/A
Bounding Box North Lat 90.0
Bounding Box South Lat -90.0
Bounding Box West Long -180.0
Bounding Box East Long 180.0
Spatial Representation N/A
Spatial Resolution 1.0 degreesLatitude
1.0 degreesLongitude
2.0 degreesLatitude
2.0 degreesLongitude
Related Links N/A
Additional Information N/A
Resource Format Hierarchical Data Format File (application/x-hdf)
Standardized Resource Format ASCII
Asset Size N/A
Legal Constraints

Creative Commons Attribution 4.0 International License.

Access Constraints None
Software Implementation Language N/A

Resource Support Name Cecile Hannay
Resource Support Email
Resource Support Organization UCAR/NCAR - Climate and Global Dynamics Laboratory
Distributor N/A
Metadata Contact Name GDEX Curator
Metadata Contact Email
Metadata Contact Organization UCAR/NCAR - GDEX

Author Bacmeister, Julio
Hannay, Cecile
Publisher UCAR/NCAR - GDEX
Publication Date 2020-09-28
Digital Object Identifier (DOI)
Alternate Identifier N/A
Resource Version N/A
Topic Category N/A
Progress N/A
Metadata Date 2022-07-21T12:23:37-06:00
Metadata Record Identifier edu.ucar.gdex::4d1d94aa-52e5-4eb4-86f7-538512a292de
Metadata Language eng; USA
Suggested Citation Bacmeister, Julio, Hannay, Cecile. (2020). Datasets used in Bacmeister et al, JAMES (2020). " CO2 increase experiments ...". UCAR/NCAR - GDEX. Accessed 29 September 2023.

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