FAIR v1.3: a simple emissions-based impulse response and carbon cycle model
Simple climate models can be valuable if they are able to replicate aspects of complex fully coupled earth system models. Larger ensembles can be produced, enabling a probabilistic view of future climate change. A simple emissions-based climate model, FAIR, is presented, which calculates atmosph...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-06-01
|
| Series: | Geoscientific Model Development |
| Online Access: | https://www.geosci-model-dev.net/11/2273/2018/gmd-11-2273-2018.pdf |
| _version_ | 1811207913847390208 |
|---|---|
| author | C. J. Smith P. M. Forster M. Allen N. Leach R. J. Millar R. J. Millar G. A. Passerello L. A. Regayre |
| author_facet | C. J. Smith P. M. Forster M. Allen N. Leach R. J. Millar R. J. Millar G. A. Passerello L. A. Regayre |
| author_sort | C. J. Smith |
| collection | DOAJ |
| description | Simple climate models can be valuable if they are able to
replicate aspects of complex fully coupled earth system models. Larger
ensembles can be produced, enabling a probabilistic view of future climate
change. A simple emissions-based climate model, FAIR, is presented, which
calculates atmospheric concentrations of greenhouse gases and effective
radiative forcing (ERF) from greenhouse gases, aerosols, ozone and other
agents. Model runs are constrained to observed temperature change from 1880
to 2016 and produce a range of future projections under the Representative
Concentration Pathway (RCP) scenarios. The constrained estimates of
equilibrium climate sensitivity (ECS), transient climate response (TCR) and
transient climate response to cumulative CO<sub>2</sub> emissions (TCRE) are 2.86
(2.01 to 4.22) K, 1.53 (1.05 to 2.41) K and 1.40 (0.96 to
2.23) K (1000 GtC)<sup>−1</sup> (median and 5–95 % credible intervals). These are
in good agreement with the
likely Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5)
range, noting that AR5 estimates were derived from a combination of climate
models, observations and expert judgement. The ranges of future projections
of temperature and ranges of estimates of ECS, TCR and TCRE are somewhat
sensitive to the prior distributions of ECS∕TCR parameters but less
sensitive to the ERF from a doubling of CO<sub>2</sub> or the observational
temperature dataset used to constrain the ensemble. Taking these
sensitivities into account, there is no evidence to suggest that the median
and credible range of observationally constrained TCR or ECS differ from
climate model-derived estimates. The range of temperature projections under
RCP8.5 for 2081–2100 in the constrained FAIR model ensemble is lower than
the emissions-based estimate reported in AR5 by half a degree, owing to
differences in forcing assumptions and ECS∕TCR distributions. |
| first_indexed | 2024-04-12T04:13:13Z |
| format | Article |
| id | doaj.art-72865b136af34a52827555e76d8253c8 |
| institution | Directory Open Access Journal |
| issn | 1991-959X 1991-9603 |
| language | English |
| last_indexed | 2024-04-12T04:13:13Z |
| publishDate | 2018-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Geoscientific Model Development |
| spelling | doaj.art-72865b136af34a52827555e76d8253c82022-12-22T03:48:27ZengCopernicus PublicationsGeoscientific Model Development1991-959X1991-96032018-06-01112273229710.5194/gmd-11-2273-2018FAIR v1.3: a simple emissions-based impulse response and carbon cycle modelC. J. Smith0P. M. Forster1M. Allen2N. Leach3R. J. Millar4R. J. Millar5G. A. Passerello6L. A. Regayre7School of Earth and Environment, University of Leeds, Leeds, UKSchool of Earth and Environment, University of Leeds, Leeds, UKAtmospheric Physics Department, University of Oxford, Oxford, UKAtmospheric Physics Department, University of Oxford, Oxford, UKCollege of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UKEnvironmental Change Institute, University of Oxford, Oxford, UKSchool of Earth and Environment, University of Leeds, Leeds, UKSchool of Earth and Environment, University of Leeds, Leeds, UKSimple climate models can be valuable if they are able to replicate aspects of complex fully coupled earth system models. Larger ensembles can be produced, enabling a probabilistic view of future climate change. A simple emissions-based climate model, FAIR, is presented, which calculates atmospheric concentrations of greenhouse gases and effective radiative forcing (ERF) from greenhouse gases, aerosols, ozone and other agents. Model runs are constrained to observed temperature change from 1880 to 2016 and produce a range of future projections under the Representative Concentration Pathway (RCP) scenarios. The constrained estimates of equilibrium climate sensitivity (ECS), transient climate response (TCR) and transient climate response to cumulative CO<sub>2</sub> emissions (TCRE) are 2.86 (2.01 to 4.22) K, 1.53 (1.05 to 2.41) K and 1.40 (0.96 to 2.23) K (1000 GtC)<sup>−1</sup> (median and 5–95 % credible intervals). These are in good agreement with the likely Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) range, noting that AR5 estimates were derived from a combination of climate models, observations and expert judgement. The ranges of future projections of temperature and ranges of estimates of ECS, TCR and TCRE are somewhat sensitive to the prior distributions of ECS∕TCR parameters but less sensitive to the ERF from a doubling of CO<sub>2</sub> or the observational temperature dataset used to constrain the ensemble. Taking these sensitivities into account, there is no evidence to suggest that the median and credible range of observationally constrained TCR or ECS differ from climate model-derived estimates. The range of temperature projections under RCP8.5 for 2081–2100 in the constrained FAIR model ensemble is lower than the emissions-based estimate reported in AR5 by half a degree, owing to differences in forcing assumptions and ECS∕TCR distributions.https://www.geosci-model-dev.net/11/2273/2018/gmd-11-2273-2018.pdf |
| spellingShingle | C. J. Smith P. M. Forster M. Allen N. Leach R. J. Millar R. J. Millar G. A. Passerello L. A. Regayre FAIR v1.3: a simple emissions-based impulse response and carbon cycle model Geoscientific Model Development |
| title | FAIR v1.3: a simple emissions-based impulse response and carbon cycle model |
| title_full | FAIR v1.3: a simple emissions-based impulse response and carbon cycle model |
| title_fullStr | FAIR v1.3: a simple emissions-based impulse response and carbon cycle model |
| title_full_unstemmed | FAIR v1.3: a simple emissions-based impulse response and carbon cycle model |
| title_short | FAIR v1.3: a simple emissions-based impulse response and carbon cycle model |
| title_sort | fair v1 3 a simple emissions based impulse response and carbon cycle model |
| url | https://www.geosci-model-dev.net/11/2273/2018/gmd-11-2273-2018.pdf |
| work_keys_str_mv | AT cjsmith fairv13asimpleemissionsbasedimpulseresponseandcarboncyclemodel AT pmforster fairv13asimpleemissionsbasedimpulseresponseandcarboncyclemodel AT mallen fairv13asimpleemissionsbasedimpulseresponseandcarboncyclemodel AT nleach fairv13asimpleemissionsbasedimpulseresponseandcarboncyclemodel AT rjmillar fairv13asimpleemissionsbasedimpulseresponseandcarboncyclemodel AT rjmillar fairv13asimpleemissionsbasedimpulseresponseandcarboncyclemodel AT gapasserello fairv13asimpleemissionsbasedimpulseresponseandcarboncyclemodel AT laregayre fairv13asimpleemissionsbasedimpulseresponseandcarboncyclemodel |