Twenty-first century ocean warming, acidification, deoxygenation, and upper-ocean nutrient and primary production decline from CMIP6 model projections

Biogeosciences, Journal Year: 2020, Volume and Issue: 17(13), P. 3439 - 3470

Published: July 6, 2020

Abstract. Anthropogenic climate change is projected to lead ocean warming, acidification, deoxygenation, reductions in near-surface nutrients, and changes primary production, all of which are expected affect marine ecosystems. Here we assess projections these drivers environmental over the twenty-first century from Earth system models (ESMs) participating Coupled Model Intercomparison Project Phase 6 (CMIP6) that were forced under CMIP6 Shared Socioeconomic Pathways (SSPs). Projections compared those previous generation (CMIP5) Representative Concentration (RCPs). A total 10 CMIP5 13 used two multi-model ensembles. Under high-emission scenario SSP5-8.5, global mean (2080–2099 values relative 1870–1899) ± inter-model SD sea surface temperature, pH, subsurface (100–600 m) oxygen concentration, euphotic (0–100 nitrate depth-integrated production +3.47±0.78 ∘C, -0.44±0.005, -13.27±5.28, -1.06±0.45 mmol m−3 -2.99±9.11 %, respectively. low-emission, high-mitigation SSP1-2.6, corresponding +1.42±0.32 -0.16±0.002, -6.36±2.92, -0.52±0.23 m−3, -0.56±4.12 %. Projected exposure ecosystem depends largely on extent future emissions, consistent with studies. The ESMs generally project greater but lesser declines than comparable radiative forcing. increased warming results a general increase sensitivity CMIP5. This enhanced increases upper-ocean stratification projections, contributes ventilation. acidification primarily consequence SSPs having higher associated atmospheric CO2 concentrations their RCP analogues for same We find no reduction uncertainties, even an net uncertainties CMIP6, as

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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Climate model projections from the Scenario Model Intercomparison Project (ScenarioMIP) of CMIP6

Earth System Dynamics, Journal Year: 2021, Volume and Issue: 12(1), P. 253 - 293

Published: March 1, 2021

Abstract. The Scenario Model Intercomparison Project (ScenarioMIP) defines and coordinates the main set of future climate projections, based on concentration-driven simulations, within Coupled phase 6 (CMIP6). This paper presents a range its outcomes by synthesizing results from participating global coupled Earth system models. We limit our scope to analysis strictly geophysical outcomes: mainly averages spatial patterns change for surface air temperature precipitation. also compare CMIP6 projections CMIP5 results, especially those scenarios that were designed provide continuity across CMIP phases, at same time highlighting important differences in forcing composition, as well results. precipitation changes end century (2081–2100) encompassing Tier 1 experiments Shared Socioeconomic Pathway (SSP) (SSP1-2.6, SSP2-4.5, SSP3-7.0 SSP5-8.5) SSP1-1.9 spans larger compared CMIP5, due higher warming (by close 1.5 ∘C) reached upper 5 %–95 % envelope highest scenario (SSP5-8.5). is both wider radiative new cover sensitivities some models their predecessors. Spatial averaged over have familiar features, an variations confirms model structural be dominant source uncertainty. Models differ with respect size evolution internal variability measured individual models' initial condition ensemble spreads, according simulations available under SSP3-7.0. These suggest tendency decrease along course this scenario, result will benefit further Benefits mitigation, all else being equal terms societal drivers, appear clearly when comparing developed SSP but which different degrees mitigation been applied. It found mild overshoot few decades around mid-century, represented SSP5-3.4OS, does not affect outcome 2100, return levels gradually increasing SSP4-3.4 (not erasing possibility, however, other aspects may easily reversible). Central estimates means reach given level might biased inclusion shown faster historical period than observed. Those show reaching ∘C 1850–1900 baseline second half current decade, span between slow fast covering 20 27 years present. 2 early 2039 mean SSP5-8.5 late mid-2060s SSP1-2.6. considered (5 only until mid-2090s.

Language: Английский

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Historical and future changes in air pollutants from CMIP6 models

Atmospheric chemistry and physics, Journal Year: 2020, Volume and Issue: 20(23), P. 14547 - 14579

Published: Nov. 30, 2020

Abstract. Poor air quality is currently responsible for large impacts on human health across the world. In addition, pollutants ozone (O3) and particulate matter less than 2.5 µm in diameter (PM2.5) are also radiatively active atmosphere can influence Earth's climate. It important to understand effect of climate mitigation measures over historical period different future scenarios ascertain any from both health. The Coupled Model Intercomparison Project Phase 6 (CMIP6) presents an opportunity analyse change simulated by current generation Earth system models that include a representation chemistry aerosols (particulate matter). shared socio-economic pathways (SSPs) used within CMIP6 encompass wide range trajectories precursor emissions change, allowing improved analysis changes pollutants. Firstly, we conduct evaluation available against surface observations O3 PM2.5. consistently overestimate observed concentrations most regions seasons up 16 ppb, with diversity values Northern Hemisphere continental regions. Conversely, PM2.5 underestimated 10 µg m−3, particularly winter months, largest model near natural emission source biases when compared similar those found previous studies. Over (1850–2014) increases all regions, mid late 20th century, anthropogenic increase markedly. Large regional East South Asia annual mean 40 ppb 12 m−3 containing strong (ssp126), substantially reduced 15 However, weak action mitigating reducing pollutant (ssp370), (up ppb) 8 m−3) although, like North America Europe small reductions due reduction this scenario. A comparison individual highlights differences interaction aerosols, chemistry, sources models. projection latest shows particular trajectory could have consequences quality, near-term Differences between emphasise importance understanding how feedbacks sources, e.g. response biogenic under change.

Language: Английский

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Next-generation ensemble projections reveal higher climate risks for marine ecosystems

Nature Climate Change, Journal Year: 2021, Volume and Issue: 11(11), P. 973 - 981

Published: Oct. 21, 2021

Projections of climate change impacts on marine ecosystems have revealed long-term declines in global animal biomass and unevenly distributed fisheries. Here we apply an enhanced suite ecosystem models from the Fisheries Marine Ecosystem Model Intercomparison Project (Fish-MIP), forced by new-generation Earth system model outputs Phase 6 Coupled (CMIP6), to provide insights into how projected will affect future ocean ecosystems. Compared with previous generation CMIP5-forced Fish-MIP ensemble, new ensemble simulations show a greater decline mean under both strong-mitigation high-emissions scenarios due elevated warming, despite uncertainty net primary production scenario. Regional shifts direction changes highlight continued urgent need reduce responses help support adaptation planning.

Language: Английский

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Constraining human contributions to observed warming since the pre-industrial period

Nature Climate Change, Journal Year: 2021, Volume and Issue: 11(3), P. 207 - 212

Published: Jan. 18, 2021

Language: Английский

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A global map of local climate zones to support earth system modelling and urban-scale environmental science

Earth system science data, Journal Year: 2022, Volume and Issue: 14(8), P. 3835 - 3873

Published: Aug. 29, 2022

Abstract. There is a scientific consensus on the need for spatially detailed information urban landscapes at global scale. These data can support range of environmental services, since cities are places intense resource consumption and waste generation concentrated infrastructure human settlement exposed to multiple hazards natural anthropogenic origin. In face climate change, also required explore future urbanization pathways design strategies in order lock long-term resilience sustainability, protecting from decisions that could undermine their adaptability mitigation role. To serve this purpose, we present 100 m-resolution map local zones (LCZs), universal typology distinguish areas holistic basis, accounting typical combination micro-scale land covers associated physical properties. The LCZ map, composed 10 built 7 cover types, generated by feeding an unprecedented number labelled training earth observation images into lightweight random forest models. Its quality assessed using bootstrap cross-validation alongside thematic benchmark 150 selected functional independent open-source surface cover, imperviousness, building height, heat. As each type with generic numerical descriptions key canopy parameters regulate atmospheric responses urbanization, availability globally consistent climate-relevant description important prerequisite supporting model development creating evidence-based climate-sensitive planning policies. This dataset be downloaded https://doi.org/10.5281/zenodo.6364594 (Demuzere et al., 2022a).

Language: Английский

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The DOE E3SM Model Version 2: Overview of the Physical Model and Initial Model Evaluation

Journal of Advances in Modeling Earth Systems, Journal Year: 2022, Volume and Issue: 14(12)

Published: Oct. 31, 2022

Abstract This work documents version two of the Department Energy's Energy Exascale Earth System Model (E3SM). E3SMv2 is a significant evolution from its predecessor E3SMv1, resulting in model that nearly twice as fast and with simulated climate improved many metrics. We describe physical lower horizontal resolution configuration consisting 110 km atmosphere, 165 land, 0.5° river routing model, an ocean sea ice mesh spacing varying between 60 mid‐latitudes 30 at equator poles. The performance evaluated Coupled Intercomparison Project Phase 6 Diagnosis, Evaluation, Characterization Klima simulations augmented historical well to evaluate impacts different forcing agents. has realistic features system, notable improvements clouds precipitation compared E3SMv1. E3SMv1 suffered excessively high equilibrium sensitivity (ECS) 5.3 K. In E3SMv2, ECS reduced 4.0 K which now within plausible range based on recent World Climate Research Program assessment. However, number important biases remain including weak Atlantic Meridional Overturning Circulation, deficiencies characteristics spectral distribution tropical atmospheric variability, underestimation observed warming second half period. An analysis single‐forcing indicates correcting temperature bias would require substantial reduction magnitude aerosol‐related forcing.

Language: Английский

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Toward a better understanding of fish‐based contribution to ocean carbon flux

Limnology and Oceanography, Journal Year: 2021, Volume and Issue: 66(5), P. 1639 - 1664

Published: Feb. 17, 2021

Abstract Fishes are the dominant vertebrates in ocean, yet we know little of their contribution to carbon export flux at regional global scales. We synthesize existing information on fish‐based coastal and pelagic waters, identify gaps challenges measuring this approaches address them, recommend research priorities. Based our synthesis passive (fecal pellet sinking) active (migratory) fishes, estimated that fishes contribute an average (± standard deviation) about 16.1% 13%) total out euphotic zone. Using mean value model‐generated estimates, equates annual 1.5 ± 1.2 Pg C yr −1 . High variability estimations among previous field studies reported here highlight significant methodological variations observational present knowledge. Community‐adopted standards, improved more frequent measurements biomass fluxes stronger linkages between observations models will decrease uncertainty, increase confidence estimation flux, enable identification controlling factors account for spatial temporal variability. Better constraints key component biological pump provide a baseline understanding how ongoing climate change harvest affect role play flux.

Language: Английский

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Ocean Biogeochemistry in GFDL's Earth System Model 4.1 and Its Response to Increasing Atmospheric CO₂

Journal of Advances in Modeling Earth Systems, Journal Year: 2020, Volume and Issue: 12(10)

Published: Aug. 22, 2020

Abstract This contribution describes the ocean biogeochemical component of Geophysical Fluid Dynamics Laboratory's Earth System Model 4.1 (GFDL‐ESM4.1), assesses GFDL‐ESM4.1's capacity to capture observed patterns, and documents its response increasing atmospheric CO 2 . Notable differences relative previous generation GFDL ESM's include enhanced resolution plankton food web dynamics, refined particle remineralization, a larger number exchanges nutrients across system components. During model spin‐up, carbon drift rapidly fell below 10 Pg C per century equilibration criterion established by Coupled Climate‐Carbon Cycle Intercomparison Project (C4MIP). Simulations robustly captured large‐scale nutrient distributions, characteristics biological pump. The overexpressed phosphate limitation open hypoxia in some areas but still yielded realistic surface deep properties, including cumulative uptake since preindustrial times over last decades that is consistent with observation‐based estimates. model's direct radiative effects 200% increase from conditions (i.e., years 101–120 1% yr −1 simulation) included (a) weakened, shoaling organic pump leading 38% reduction sinking flux at 2,000 m; (b) two‐thirds calcium carbonate nonetheless generated only weak calcite compensation on time‐scales; and, contrast ESMs, (c) moderate global net primary production was amplified higher trophic levels. We conclude discussion limitations priority developments.

Language: Английский

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