Identification

Title

Carbon-concentration and carbon-climate feedbacks in CMIP6 models and their comparison to CMIP5 models

Abstract

Results from the fully and biogeochemically coupled simulations in which CO2 increases at a rate of 1 % yr(-1) (1pctCO2) from its preindustrial value are analyzed to quantify the magnitude of carbon-concentration and carbon-climate feedback parameters which measure the response of ocean and terrestrial carbon pools to changes in atmospheric CO2 concentration and the resulting change in global climate, respectively. The results are based on 11 comprehensive Earth system models from the most recent sixth) Coupled Model Intercomparison Project (CMIP6) and compared with eight models from the fifth CMIP (CMIP5). The strength of the carbon-concentration feedback is of comparable magnitudes over land (mean +/- standard deviation = 0.97 +/- 0.40 PgC ppm(-1)) and ocean (0.79 +/- 0.07 PgC ppm(-1)), while the carbon-climate feedback over land (-45.1 +/- 50.6 PgC degrees C-1) is about 3 times larger than over ocean (-17.2 +/- 5.0 PgC degrees C-1). The strength of both feedbacks is an order of magnitude more uncertain over land than over ocean as has been seen in existing studies. These values and their spread from 11 CMIP6 models have not changed significantly compared to CMIP5 models. The absolute values of feedback parameters are lower for land with models that include a representation of nitrogen cycle. The transient climate response to cumulative emissions (TCRE) from the 11 CMIP6 models considered here is 1.77 +/- 0.37 degrees C EgC(-1) and is similar to that found in CMIP5 models (1.63 +/- 0.48 degrees C EgC(-1)) but with somewhat reduced model spread. The expressions for feedback parameters based on the fully and biogeochemically coupled configurations of the 1pctCO2 simulation are simplified when the small temperature change in the biogeochemically coupled simulation is ignored. Decomposition of the terms of these simplified expressions for the feedback parameters is used to gain insight into the reasons for differing responses among ocean and land carbon cycle models.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7pg1w1r

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

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South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2020-08-18T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

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version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

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