Differences in carbon cycle and temperature projections from emission- and concentration-driven earth system model simulations

Abstract. The influence of prognostic and prescribed atmospheric CO2 concentrations ([CO2]) on the carbon uptake and temperature is investigated using all eight Earth System Models (ESMs) with relevant output variables from the Coupled Model Intercomparison Project Phase 5 (CMIP5). Under the RCP8.5 scenario, the projected [CO2] differences in 2100 vary from −19.7 to +207.3 ppm in emission-driven ESMs. Incorporation of the interactive concentrations also increases the range of global warming, computed as the 20 year average difference between 2081–2100 and 1850–1869/1861–1880, by 49% from 2.36 K (i.e. ranging from 3.11 to 5.47 K) in the concentration-driven simulations to 3.51 K in the emission-driven simulations. The observed seasonal amplitude of global [CO2] from 1980–2011 is about 1.2–5.3 times as large as those from the eight emission-driven ESMs, while the [CO2] seasonality is simply neglected in concentration-driven ESMs, suggesting the urgent need of ESM improvements in this area. The temperature-concentration feedback parameter α is more sensitive to [CO2] (e.g. during 1980–2005 versus 2075–2100) than how [CO2] is handled (i.e. prognostic versus prescribed). This sensitivity can be substantially reduced by using a more appropriate parameter α' computed from the linear regression of temperature change versus that of the logarithm of [CO2]. However, the inter-model relative variations of both α and α' remain large, suggesting the need of more detailed studies to understand and hopefully reduce these discrepancies.

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Description of the MIROC-ES2L Earth system model and evaluation of its climate–biogeochemical processes and feedbacks

10.5194/gmd-2019-275 ◽

2019 ◽

Cited By ~ 5

Author(s):

Tomohiro Hajima ◽

Michio Watanabe ◽

Akitomo Yamamoto ◽

Hiroaki Tatebe ◽

Maki A. Noguchi ◽

...

Keyword(s):

Carbon Cycle ◽

Nitrogen Cycle ◽

Carbon Sink ◽

Coupled Model ◽

System Model ◽

Climate Response ◽

Earth System ◽

Model Intercomparison ◽

Transient Climate Response ◽

Intercomparison Project

Abstract. This study developed a new Model for Interdisciplinary Research on Climate, Earth System version2 for Long-term simulations (MIROC-ES2L) Earth system model (ESM) using a state-of-the-art climate model as the physical core. This model embeds a terrestrial biogeochemical component with explicit carbon–nitrogen interaction to account for soil nutrient control on plant growth and the land carbon sink. The model’s ocean biogeochemical component is largely updated to simulate biogeochemical cycles of carbon, nitrogen, phosphorus, iron, and oxygen such that oceanic primary productivity can be controlled by multiple nutrient limitations. The ocean nitrogen cycle is coupled with the land component via river discharge processes, and external inputs of iron from pyrogenic and lithogenic sources are considered. Comparison of a historical simulation with observation studies showed the model could reproduce reasonable historical changes in climate, the carbon cycle, and other biogeochemical variables together with reasonable spatial patterns of distribution of the present-day condition. The model demonstrated historical human perturbation of the nitrogen cycle through land use and agriculture, and it simulated the resultant impact on the terrestrial carbon cycle. Sensitivity analyses in preindustrial conditions revealed modeled ocean biogeochemistry could be changed regionally (but substantially) by nutrient inputs from the atmosphere and rivers. Through an idealized experiment of a 1 %CO2 increase scenario, we found the transient climate response (TCR) in the model is 1.5 K, i.e., approximately 70 % that of our previous model. The cumulative airborne fraction (AF) is also reduced by 15 % because of the intensified land carbon sink, resulting in an AF close to the multimodel mean of the Coupled Model Intercomparison Project Phase 5 (CMIP5) ESMs. The transient climate response to cumulative carbon emission (TCRE) is 1.3 K EgC−1, i.e., slightly smaller than the average of the CMIP5 ESMs, suggesting optimistic model performance in future climate projections. This model and the simulation results are contributing to the Coupled Model Intercomparison Project Phase 6 (CMIP6). The ESM could help further understanding of climate–biogeochemical interaction mechanisms, projections of future environmental changes, and exploration of our future options regarding sustainable development by evolving the processes of climate, biogeochemistry, and human activities in a holistic and interactive manner.

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Estimated effect of the permafrost carbon feedback on the zero emissions commitment to climate change

10.5194/bg-2021-136 ◽

2021 ◽

Author(s):

Andrew Hugh MacDougall

Keyword(s):

Climate Change ◽

Carbon Cycle ◽

Co2 Emissions ◽

System Model ◽

Earth System ◽

Model Intercomparison ◽

Lag Effect ◽

Intercomparison Project ◽

Potential Impact ◽

Earth System Models

Abstract. Zero Emissions Commitment (ZEC), the expected change in global temperature following the cessation of CO2 emissions has recently been assessed by the Zero Emissions Commitment Model Intercomparison Project (ZECMIP). ZECMIP concluded that the component of ZEC from CO2 emissions will likely be close to zero in the decades following the cessation of emissions. However, of the 18 Earth system models that participated in ZECMIP only two included a representation of the permafrost carbon feedback to climate change. To better assess the potential impact of permafrost carbon decay on ZEC a series of perturbed parameter experiments are here conducted with an Earth system model of intermediate complexity. The experiment suggest that the permafrost carbon cycle feedback will directly add 0.06 [0.02 to 0.14] °C to the benchmark ZEC value assesses 50 years after 1000 PgC of CO2 has been emitted to the atmosphere. An additional 0.04 [0 to 0.06] °C is likely to been added relative to the benchmark ZEC value from the thaw-lag effect unaccounted for in the ZECMIP experiment design. Overall we assess that the permafrost carbon feedback is unlikely to change the assessment that ZEC is close to zero on decadal timescales, however the feedback is expected to become more important over the coming centuries.

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ESM-SnowMIP: Assessing models and quantifying snow-related climate feedbacks

10.5194/gmd-2018-153 ◽

2018 ◽

Cited By ~ 3

Author(s):

Gerhard Krinner ◽

Chris Derksen ◽

Richard Essery ◽

Mark Flanner ◽

Stefan Hagemann ◽

...

Keyword(s):

Land Surface ◽

Coupled Model ◽

Global Scale ◽

Earth System ◽

Climate Feedbacks ◽

Model Intercomparison ◽

Scale Modeling ◽

Intercomparison Project ◽

Modelling Effort ◽

Earth System Models

Abstract. This paper describes ESM-SnowMIP, an international coordinated modelling effort to evaluate current snow schemes against local and global observations in a wide variety of settings, including snow schemes that are included in Earth System Models. The project aims at identifying crucial processes and snow characteristics that need to be improved in snow models in the context of local- and global-scale modeling. A further objective of ESM-SnowMIP is to better quantify snow-related feedbacks in the Earth system. ESM-SnowMIP is tightly linked to the Land Surface, Snow and Soil Moisture Model Intercomparison Project, which in turn is part of the 6th phase of the Coupled Model Intercomparison Project (CMIP6).

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ESM-SnowMIP: assessing snow models and quantifying snow-related climate feedbacks

Geoscientific Model Development ◽

10.5194/gmd-11-5027-2018 ◽

2018 ◽

Vol 11 (12) ◽

pp. 5027-5049 ◽

Cited By ~ 32

Author(s):

Gerhard Krinner ◽

Chris Derksen ◽

Richard Essery ◽

Mark Flanner ◽

Stefan Hagemann ◽

...

Keyword(s):

Land Surface ◽

Coupled Model ◽

Global Scale ◽

Earth System ◽

Climate Feedbacks ◽

Model Intercomparison ◽

Scale Modelling ◽

Intercomparison Project ◽

Modelling Effort ◽

Earth System Models

Abstract. This paper describes ESM-SnowMIP, an international coordinated modelling effort to evaluate current snow schemes, including snow schemes that are included in Earth system models, in a wide variety of settings against local and global observations. The project aims to identify crucial processes and characteristics that need to be improved in snow models in the context of local- and global-scale modelling. A further objective of ESM-SnowMIP is to better quantify snow-related feedbacks in the Earth system. Although it is not part of the sixth phase of the Coupled Model Intercomparison Project (CMIP6), ESM-SnowMIP is tightly linked to the CMIP6-endorsed Land Surface, Snow and Soil Moisture Model Intercomparison (LS3MIP).

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Estimated effect of the permafrost carbon feedback on the zero emissions commitment to climate change

Biogeosciences ◽

10.5194/bg-18-4937-2021 ◽

2021 ◽

Vol 18 (17) ◽

pp. 4937-4952

Author(s):

Andrew H. MacDougall

Keyword(s):

Climate Change ◽

Carbon Cycle ◽

Co2 Emissions ◽

System Model ◽

Earth System ◽

Model Intercomparison ◽

Lag Effect ◽

Intercomparison Project ◽

Potential Impact ◽

Earth System Models

Abstract. Zero Emissions Commitment (ZEC), the expected change in global temperature following the cessation of anthropogenic greenhouse gas emissions, has recently been assessed by the Zero Emissions Commitment Model Intercomparison Project (ZECMIP). ZECMIP concluded that the component of ZEC from CO2 emissions will likely be close to zero in the decades following the cessation of emissions. However, of the 18 Earth system models that participated in ZECMIP only 2 included a representation of the permafrost carbon feedback to climate change. To better assess the potential impact of permafrost carbon decay on ZEC, a series of perturbed parameter experiments are here conducted with an Earth system model of intermediate complexity. The experiment suggests that the permafrost carbon cycle feedback will directly add 0.06 [0.02 to 0.14] ∘C to the benchmark the ZEC value assesses 50 years after 1000 Pg C of CO2 has been emitted to the atmosphere. An additional 0.04 [0 to 0.06] ∘C is likely to been added relative to the benchmark ZEC value from the thaw-lag effect unaccounted for in the ZECMIP experiment design. Overall I assess that the permafrost carbon feedback is unlikely to change the assessment that ZEC is close to zero on decadal timescales; however, the feedback is expected to become more important over the coming centuries.

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The Norwegian Earth System Model, NorESM2 – Evaluation of theCMIP6 DECK and historical simulations

10.5194/gmd-2019-378 ◽

2020 ◽

Cited By ~ 20

Author(s):

Øyvind Seland ◽

Mats Bentsen ◽

Lise Seland Graff ◽

Dirk Olivié ◽

Thomas Toniazzo ◽

...

Keyword(s):

Sea Ice ◽

Deep Convection ◽

Coupled Model ◽

Momentum Conservation ◽

Earth System Model ◽

System Model ◽

Earth System ◽

Model Intercomparison ◽

Intercomparison Project ◽

The Stability

Abstract. The second version of the fully coupled Norwegian Earth System Model (NorESM2) is presented and evaluated. NorESM2 is based on the second version of the Community Earth System Model (CESM2), but has entirely different ocean and ocean biogeochemistry models; a new module for aerosols in the atmosphere model along with aerosol-radiation-cloud interactions and changes related to the moist energy formulation, deep convection scheme and angular momentum conservation; modified albedo and air-sea turbulent flux calculations; and minor changes to land and sea ice models. We show results from low (∼2°) and medium (∼1°) atmosphere-land resolution versions of NorESM2 that have both been used to carry out simulations for the sixth phase of the Coupled Model Intercomparison Project (CMIP6). The stability of the pre-industrial climate and the sensitivity of the model to abrupt and gradual quadrupling of CO2 is assessed, along with the ability of the model to simulate the historical climate under the CMIP6 forcings. As compared to observations and reanalyses, NorESM2 represents an improvement over previous versions of NorESM in most aspects. NorESM2 is less sensitive to greenhouse gas forcing than its predecessors, with an equilibrium climate sensitivity of 2.5 K in both resolutions on a 150 year frame. We also consider the model response to future scenarios as defined by selected shared socioeconomic pathways (SSP) from the Scenario Model Intercomparison Project defined under CMIP6. Under the four scenarios SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5, the warming in the period 2090–2099 compared to 1850–1879 reaches 1.3, 2.2, 3.0, and 3.9 K in NorESM2-LM, and 1.3, 2.1, 3.1, and 3.9 K in NorESM–MM, robustly similar in both resolutions. NorESM2-LM shows a rather satisfactorily evolution of recent sea ice area. In NorESM2-LM an ice free Arctic Ocean is only avoided in the SSP1-2.6 scenario.

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Overview of the Norwegian Earth System Model (NorESM2) and key climate response of CMIP6 DECK, historical, and scenario simulations

Geoscientific Model Development ◽

10.5194/gmd-13-6165-2020 ◽

2020 ◽

Vol 13 (12) ◽

pp. 6165-6200

Author(s):

Øyvind Seland ◽

Mats Bentsen ◽

Dirk Olivié ◽

Thomas Toniazzo ◽

Ada Gjermundsen ◽

...

Keyword(s):

Sea Ice ◽

Climate Sensitivity ◽

Time Window ◽

Coupled Model ◽

Momentum Conservation ◽

Earth System Model ◽

System Model ◽

Earth System ◽

Model Intercomparison ◽

Intercomparison Project

Abstract. The second version of the coupled Norwegian Earth System Model (NorESM2) is presented and evaluated. NorESM2 is based on the second version of the Community Earth System Model (CESM2) and shares with CESM2 the computer code infrastructure and many Earth system model components. However, NorESM2 employs entirely different ocean and ocean biogeochemistry models. The atmosphere component of NorESM2 (CAM-Nor) includes a different module for aerosol physics and chemistry, including interactions with cloud and radiation; additionally, CAM-Nor includes improvements in the formulation of local dry and moist energy conservation, in local and global angular momentum conservation, and in the computations for deep convection and air–sea fluxes. The surface components of NorESM2 have minor changes in the albedo calculations and to land and sea-ice models. We present results from simulations with NorESM2 that were carried out for the sixth phase of the Coupled Model Intercomparison Project (CMIP6). Two versions of the model are used: one with lower (∼ 2∘) atmosphere–land resolution and one with medium (∼ 1∘) atmosphere–land resolution. The stability of the pre-industrial climate and the sensitivity of the model to abrupt and gradual quadrupling of CO2 are assessed, along with the ability of the model to simulate the historical climate under the CMIP6 forcings. Compared to observations and reanalyses, NorESM2 represents an improvement over previous versions of NorESM in most aspects. NorESM2 appears less sensitive to greenhouse gas forcing than its predecessors, with an estimated equilibrium climate sensitivity of 2.5 K in both resolutions on a 150-year time frame; however, this estimate increases with the time window and the climate sensitivity at equilibration is much higher. We also consider the model response to future scenarios as defined by selected Shared Socioeconomic Pathways (SSPs) from the Scenario Model Intercomparison Project defined under CMIP6. Under the four scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5), the warming in the period 2090–2099 compared to 1850–1879 reaches 1.3, 2.2, 3.0, and 3.9 K in NorESM2-LM, and 1.3, 2.1, 3.1, and 3.9 K in NorESM-MM, robustly similar in both resolutions. NorESM2-LM shows a rather satisfactory evolution of recent sea-ice area. In NorESM2-LM, an ice-free Arctic Ocean is only avoided in the SSP1-2.6 scenario.

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Caracterização dos Diferentes Tipos de El Niño e seus Impactos na América do Sul a Partir de Dados Observados e Modelados

Revista Brasileira de Meteorologia ◽

10.1590/0102-7786334015 ◽

2019 ◽

Vol 34 (1) ◽

pp. 43-67

Author(s):

Juarez Viegas ◽

Rita Valéria Andreoli ◽

Mary Toshie Kayano ◽

Luiz Antonio Candido ◽

Rodrigo Augusto Ferreira de Souza ◽

...

Keyword(s):

El Niño ◽

El Nino ◽

Coupled Model ◽

System Model ◽

Earth System ◽

Model Intercomparison ◽

Environmental Model ◽

Global Environmental ◽

Intercomparison Project ◽

Hadley Centre

Resumo Estudos recentes têm apontado para a existência de dois tipos de eventos de El Niño (EN): EN do Pacífico oriental ou Canônico (EP, sigla em inglês) e EN do Pacífico Central ou Modoki (CP, sigla em inglês). Neste estudo, foram utilizados dados observados e de três modelos do Coupled Model Intercomparison Project phase 5 (CMIP5) para avaliar o impacto dos dois tipos de EN na precipitação da América do Sul desde o trimestre de Junho-Agosto do ano inicial do evento até Março-Maio do ano seguinte. O modelo do Centre National de Recherches Météorologiques (CNRM-CM5) apresentou o melhor desempenho para reproduzir os padrões anômalos observados de TSM para os tipos de EN CP e EP. O padrão anômalo da precipitação observada associado a eventos EN foi mais marcante durante o verão austral. No caso do EN EP, tal padrão caracterizou-se por precipitação acima (abaixo) da normal no sudeste (norte/noroeste) da América do Sul. Este padrão foi reproduzido pelos modelos CNRM-CM5 e Hadley Centre Global Environmental Model (HadGEM2-ES). O Max Plank Institute Earth System model (MPI-ESM-LR) reproduziu a redução de chuva no norte, porém não reproduziu o aumento anômalo no sudeste e redução no noroeste do continente. No caso do EN CP, o impacto observado nas chuvas da América do Sul durante o verão caracterizou-se por escassez (excesso) no norte/noroeste (sudeste). Este padrão foi reproduzido pelos modelos, entretanto, os modelos HadGEM2-ES e MPI-ESM-LR mostraram índices pluviométricos no nordeste do Brasil menores do que os observados. As diferenças na representação dos padrões de teleconexões em resposta ao EN explicam as diferenças entre os padrões simulados.

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

10.5194/egusphere-egu2020-6124 ◽

2020 ◽

Cited By ~ 1

Author(s):

Vivek Arora ◽

Anna Katavouta ◽

Richard Williams ◽

Chris Jones ◽

Victor Brovkin ◽

...

Keyword(s):

Global Climate ◽

Coupled Model ◽

Cmip5 Models ◽

Earth System ◽

Climate Feedbacks ◽

Model Intercomparison ◽

Small Temperature ◽

Mean Values ◽

Intercomparison Project ◽

Earth System Models

Results from the fully-, biogeochemically-, and radiatively-coupled simulations in which CO2 increases at a rate of 1% per year (1pctCO2) from its pre-industrial value are analyzed to quantify the magnitude of two feedback parameters which characterize the coupled carbon-climate system. These feedback parameters quantify the response of ocean and terrestrial carbon pools to changes in atmospheric CO2 concentration and the resulting change in global climate. The results are based on eight comprehensive Earth system models from the fifth Coupled Model Intercomparison Project (CMIP5) and eleven models from the sixth CMIP (CMIP6). The comparison of model results from two CMIP phases shows that, for both land and ocean, the model mean values of the feedback parameters and their multi-model spread has not changed significantly across the two CMIP phases. The absolute values of feedback parameters are lower for land with models that include a representation of nitrogen cycle. The sensitivity of feedback parameters to the three different ways in which they may be calculated is shown and, consistent with existing studies, the most relevant definition is that calculated using results from the fully- and biogeochemically-coupled configurations. Based on these two simulations simplified expressions for the feedback parameters are obtained when the small temperature change in the biogeochemically-coupled simulation is ignored. Decomposition of the terms of these simplified expressions for the feedback parameters allows identification of the reasons for differing responses among ocean and land carbon cycle models.

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Workflow and tools to analyse the PMIP4-CMIP6 ensemble

10.5194/egusphere-egu21-2476 ◽

2021 ◽

Author(s):

Anni Zhao ◽

Chris Brierley

Keyword(s):

Case Studies ◽

Coupled Model ◽

Important Case ◽

Earth System ◽

Model Intercomparison ◽

Past Climate ◽

The Past ◽

The Earth ◽

Intercomparison Project

Experiment outputs are now available from the Coupled Model Intercomparison Project&#8217;s 6th phase (CMIP6) and the past climate experiments defined in the Model Intercomparison Project&#8217;s 4th phase (PMIP4). All of this output is freely available from the Earth System Grid Federation (ESGF). Yet there are overheads in analysing this resource that may prove complicated or prohibitive. Here we document the steps taken by ourselves to produce ensemble analyses covering past and future simulations. We outline the strategy used to curate, adjust the monthly calendar aggregation and process the information downloaded from the ESGF. The results of these steps were used to perform analysis for several of the initial publications arising from PMIP4. We provide post-processed fields for each simulation, such as climatologies and common measures of variability. Example scripts used to visualise and analyse these fields is provided for several important case studies.

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