The Community Earth System Model Version 2 (CESM2)

Journal of Advances in Modeling Earth Systems, Journal Year: 2020, Volume and Issue: 12(2)

Published: Jan. 17, 2020

An overview of the Community Earth System Model Version 2 (CESM2) is provided, including a discussion challenges encountered during its development and how they were addressed. In addition, an evaluation pair CESM2 long preindustrial control historical ensemble simulations presented. These performed using nominal 1° horizontal resolution configuration coupled model with both "low-top" (40 km, limited chemistry) "high-top" (130 comprehensive versions atmospheric component. contains many substantial science infrastructure improvements new capabilities since previous major release, CESM1, resulting in improved comparison to CESM1 available observations. include reductions low-latitude precipitation shortwave cloud forcing biases; better representation Madden-Julian Oscillation; El Niño-Southern Oscillation-related teleconnections; global land carbon accumulation trend that agrees well observationally based estimates. Most tropospheric surface features low- high-top are very similar each other, so these present configurations. has equilibrium climate sensitivity 5.1–5.3 °C, larger than primarily due combination relatively small changes microphysics boundary layer parameters. contrast, CESM2's transient response 1.9–2.0 °C comparable CESM1. The outputs from other research community, represent contributions Coupled Intercomparison Project Phase 6.

Language: Английский

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Global Carbon Budget 2020

Earth system science data, Journal Year: 2020, Volume and Issue: 12(4), P. 3269 - 3340

Published: Dec. 10, 2020

Abstract. Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, terrestrial biosphere in a changing climate – “global budget” is important to better understand global cycle, support development policies, project future change. Here we describe synthesize data sets methodology quantify five major components budget uncertainties. Fossil CO2 (EFOS) are based on energy statistics cement production data, while from land-use change (ELUC), mainly deforestation, land use bookkeeping models. Atmospheric concentration measured directly its growth rate (GATM) computed annual changes concentration. The ocean sink (SOCEAN) (SLAND) estimated with process models constrained by observations. resulting imbalance (BIM), difference between total biosphere, measure imperfect understanding contemporary cycle. All uncertainties reported as ±1σ. For last decade available (2010–2019), EFOS was 9.6 ± 0.5 GtC yr−1 excluding carbonation (9.4 when included), ELUC 1.6 0.7 yr−1. same decade, GATM 5.1 0.02 (2.4 0.01 ppm yr−1), SOCEAN 2.5 0.6 yr−1, SLAND 3.4 0.9 BIM −0.1 indicating near balance sources sinks over decade. year 2019 alone, only about 0.1 % fossil increasing 9.9 (9.7 1.8 for 11.5 (42.2 3.3 GtCO2). Also 2019, 5.4 0.2 (2.5 2.6 3.1 1.2 0.3 GtC. atmospheric reached 409.85 averaged 2019. Preliminary 2020, accounting COVID-19-induced emissions, suggest decrease relative −7 (median estimate) individual estimates four studies −6 %, (−3 −11 %), −13 %. Overall, mean trend consistently period 1959–2019, but discrepancies up 1 persist representation semi-decadal variability fluxes. Comparison diverse approaches observations shows (1) no consensus (2) persistent low agreement different methods magnitude flux northern extra-tropics, (3) an apparent discrepancy outside tropics, particularly Southern Ocean. This living update documents used this new progress cycle compared previous publications set (Friedlingstein et al., 2019; Le Quéré 2018b, a, 2016, 2015b, 2014, 2013). presented work at https://doi.org/10.18160/gcp-2020 2020).

Language: Английский

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Global Carbon Budget 2019

Earth system science data, Journal Year: 2019, Volume and Issue: 11(4), P. 1783 - 1838

Published: Dec. 4, 2019

Abstract. Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, terrestrial biosphere – “global budget” is important to better understand global cycle, support development climate policies, project future change. Here we describe data sets methodology quantify five major components budget uncertainties. Fossil CO2 (EFF) are based on energy statistics cement production data, while from land use change (ELUC), mainly deforestation, bookkeeping models. Atmospheric concentration measured directly its growth rate (GATM) computed annual changes in concentration. The ocean sink (SOCEAN) (SLAND) estimated with process models constrained by observations. resulting imbalance (BIM), difference between total biosphere, a measure imperfect understanding contemporary cycle. All uncertainties reported as ±1σ. For last decade available (2009–2018), EFF was 9.5±0.5 GtC yr−1, ELUC 1.5±0.7 GATM 4.9±0.02 yr−1 (2.3±0.01 ppm yr−1), SOCEAN 2.5±0.6 SLAND 3.2±0.6 BIM 0.4 indicating overestimated and/or underestimated sinks. year 2018 alone, about 2.1 % fossil increased 10.0±0.5 reaching 10 for first time history, 11.5±0.9 (42.5±3.3 GtCO2). Also 2018, 5.1±0.2 (2.4±0.1 2.6±0.6 3.5±0.7 0.3 GtC. atmospheric reached 407.38±0.1 averaged over 2018. 2019, preliminary 6–10 months indicate reduced +0.6 (range −0.2 1.5 %) national projections China, USA, EU, India gross domestic product corrected recent intensity economy rest world. Overall, mean trend consistently period 1959–2018, but discrepancies up 1 persist representation semi-decadal variability fluxes. A detailed comparison individual estimates introduction broad range observations shows (1) no consensus decade, (2) persistent low agreement different methods magnitude flux northern extra-tropics, (3) an apparent underestimation outside tropics. This living update documents used this new progress cycle compared previous publications set (Le Quéré et al., 2018a, b, 2016, 2015a, 2014, 2013). generated work at https://doi.org/10.18160/gcp-2019 (Friedlingstein 2019).

Language: Английский

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Global Carbon Budget 2021

Earth system science data, Journal Year: 2022, Volume and Issue: 14(4), P. 1917 - 2005

Published: April 26, 2022

Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, terrestrial biosphere in a changing climate is critical to better understand global cycle, support development policies, project future change. Here we describe synthesize datasets methodology quantify five major components budget uncertainties. Fossil CO2 (EFOS) are based on energy statistics cement production data, while from land-use change (ELUC), mainly deforestation, land use data bookkeeping models. Atmospheric concentration measured directly, its growth rate (GATM) computed annual changes concentration. The ocean sink (SOCEAN) estimated with biogeochemistry models observation-based products. (SLAND) dynamic vegetation resulting imbalance (BIM), difference between total biosphere, measure imperfect understanding contemporary cycle. All uncertainties reported as ±1σ. For first time, an approach shown reconcile our ELUC estimate one national greenhouse gas inventories, supporting collective countries' progress. year 2020, EFOS declined by 5.4 % relative 2019, fossil at 9.5 ± 0.5 GtC yr−1 (9.3 when carbonation included), was 0.9 0.7 yr−1, for emission 10.2 0.8 (37.4 2.9 GtCO2). Also, GATM 5.0 0.2 (2.4 0.1 ppm yr−1), SOCEAN 3.0 0.4 SLAND 1 BIM −0.8 yr−1. atmospheric averaged over 2020 reached 412.45 ppm. Preliminary 2021 suggest rebound +4.8 (4.2 %) globally. Overall, mean trend consistently period 1959–2020, but discrepancies up persist representation semi-decadal variability fluxes. Comparison estimates multiple approaches observations shows (1) persistent large uncertainty emissions, (2) low agreement different methods magnitude flux northern extra-tropics, (3) discrepancy strength last decade. This living update documents used this new progress cycle compared previous publications dataset (Friedlingstein et al., 2019; Le Quéré 2018b, a, 2016, 2015b, 2014, 2013). presented work available https://doi.org/10.18160/gcp-2021 2021).

Language: Английский

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Global Carbon Budget 2022

Earth system science data, Journal Year: 2022, Volume and Issue: 14(11), P. 4811 - 4900

Published: Nov. 11, 2022

Abstract. Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, terrestrial biosphere in a changing climate is critical to better understand global cycle, support development policies, project future change. Here we describe synthesize data sets methodologies quantify five major components budget uncertainties. Fossil CO2 (EFOS) are based on energy statistics cement production data, while from land-use change (ELUC), mainly deforestation, land use bookkeeping models. Atmospheric concentration measured directly, its growth rate (GATM) computed annual changes concentration. The ocean sink (SOCEAN) estimated with biogeochemistry models observation-based products. (SLAND) dynamic vegetation resulting imbalance (BIM), difference between total biosphere, measure imperfect understanding contemporary cycle. All uncertainties reported as ±1σ. For year 2021, EFOS increased by 5.1 % relative 2020, fossil at 10.1 ± 0.5 GtC yr−1 (9.9 when carbonation included), ELUC was 1.1 0.7 yr−1, for emission (including sink) 10.9 0.8 (40.0 2.9 GtCO2). Also, GATM 5.2 0.2 (2.5 0.1 ppm yr−1), SOCEAN 0.4 SLAND 3.5 0.9 BIM −0.6 (i.e. sources were too low or sinks high). atmospheric averaged over 2021 reached 414.71 ppm. Preliminary 2022 suggest an increase +1.0 (0.1 1.9 %) globally reaching 417.2 ppm, more than 50 above pre-industrial levels (around 278 ppm). Overall, mean trend consistently period 1959–2021, but discrepancies up 1 persist representation semi-decadal variability fluxes. Comparison estimates multiple approaches observations shows (1) persistent large uncertainty estimate emissions, (2) agreement different methods magnitude flux northern extratropics, (3) discrepancy strength last decade. This living update documents used this new progress cycle compared previous publications set. presented work available https://doi.org/10.18160/GCP-2022 (Friedlingstein et al., 2022b).

Language: Английский

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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, Journal Year: 2020, Volume and Issue: 13(12), P. 6165 - 6200

Published: Dec. 4, 2020

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

Language: Английский

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Global Carbon Budget 2023

Earth system science data, Journal Year: 2023, Volume and Issue: 15(12), P. 5301 - 5369

Published: Nov. 30, 2023

Abstract. Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, terrestrial biosphere in a changing climate is critical to better understand global cycle, support development policies, project future change. Here we describe synthesize data sets methodology quantify five major components budget uncertainties. Fossil CO2 (EFOS) are based on energy statistics cement production data, while from land-use change (ELUC), mainly deforestation, bookkeeping models. Atmospheric concentration measured directly, its growth rate (GATM) computed annual changes concentration. The ocean sink (SOCEAN) estimated with biogeochemistry models observation-based fCO2 products. (SLAND) dynamic vegetation Additional lines evidence land sinks provided by atmospheric inversions, oxygen measurements, Earth system resulting imbalance (BIM), difference between total biosphere, measure imperfect incomplete understanding contemporary cycle. All uncertainties reported as ±1σ. For year 2022, EFOS increased 0.9 % relative 2021, fossil at 9.9±0.5 Gt C yr−1 (10.2±0.5 when carbonation not included), ELUC was 1.2±0.7 yr−1, for emission (including sink) 11.1±0.8 (40.7±3.2 yr−1). Also, GATM 4.6±0.2 (2.18±0.1 ppm yr−1; denotes parts per million), SOCEAN 2.8±0.4 SLAND 3.8±0.8 BIM −0.1 (i.e. sources marginally too low or high). averaged over 2022 reached 417.1±0.1 ppm. Preliminary 2023 suggest an increase +1.1 (0.0 2.1 %) globally reaching 419.3 ppm, 51 above pre-industrial level (around 278 1750). Overall, mean trend consistently period 1959–2022, near-zero overall imbalance, although discrepancies up around 1 persist representation semi-decadal variability fluxes. Comparison estimates multiple approaches observations shows following: (1) persistent large uncertainty estimate emissions, (2) agreement different methods magnitude flux northern extra-tropics, (3) discrepancy strength last decade. This living-data update documents applied this most recent well evolving community presented work available https://doi.org/10.18160/GCP-2023 (Friedlingstein et al., 2023).

Language: Английский

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Global human-made mass exceeds all living biomass

Nature, Journal Year: 2020, Volume and Issue: 588(7838), P. 442 - 444

Published: Dec. 9, 2020

Language: Английский

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Perspectives on the Future of Land Surface Models and the Challenges of Representing Complex Terrestrial Systems

Journal of Advances in Modeling Earth Systems, Journal Year: 2020, Volume and Issue: 12(4)

Published: March 11, 2020

Abstract Land surface models (LSMs) are a vital tool for understanding, projecting, and predicting the dynamics of land its role within Earth system, under global change. Driven by need to address set key questions, LSMs have grown in complexity from simplified representations biophysics encompass broad interrelated processes spanning disciplines biophysics, biogeochemistry, hydrology, ecosystem ecology, community human management, societal impacts. This vast scope complexity, while warranted problems designed solve, has led enormous challenges understanding attributing differences between LSM predictions. Meanwhile, wide range spatial scales that govern heterogeneity, spectrum timescales dynamics, create tractably representing LSMs. We identify three “grand challenges” development use LSMs, based around these issues: managing process parametric across asked changing world. In this review, we discuss progress been made, as well promising directions forward, each challenges.

Language: Английский

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

Biogeosciences, Journal Year: 2020, Volume and Issue: 17(16), P. 4173 - 4222

Published: Aug. 18, 2020

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

Language: Английский

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