Multi-century dynamics of the climate and carbon cycle under both high and net negative emissions scenarios DOI Creative Commons
Charles D. Koven, Vivek K. Arora, Patricia Cadule

et al.

Earth System Dynamics, Journal Year: 2022, Volume and Issue: 13(2), P. 885 - 909

Published: May 16, 2022

Abstract. Future climate projections from Earth system models (ESMs) typically focus on the timescale of this century. We use a set five ESMs and one model intermediate complexity (EMIC) to explore dynamics Earth's carbon cycles under contrasting emissions trajectories beyond century year 2300. The include very-high-emissions, unmitigated fossil-fuel-driven scenario, as well mitigation scenario that diverges first after 2040 features an “overshoot”, followed by decrease in atmospheric CO2 concentrations means large net negative emissions. In both scenarios for all considered here, terrestrial switches being sink either neutral state or source carbon, though different reasons centered geographic regions, depending scenario. ocean remains sink, albeit weakened cycle feedbacks, high-emissions overshoot global mean temperature anomaly is generally proportional cumulative emissions, with deviation proportionality governed zero commitment. Additionally, 23rd warming continues cessation several While responses qualitatively agree globally integrated zonal scenarios, land disagree dynamics, relative roles vegetation soil driving C fluxes, response CO2, timing sink–source transition, particularly lack agreement among mechanisms patterns alongside potential lagged physical cause long have stabilized, points possibility surprises 21st time horizon, even relatively mitigated which should be taken into consideration when setting policy.

Language: Английский

Climate impacts on global agriculture emerge earlier in new generation of climate and crop models DOI
Jonas Jägermeyr, Christoph Müller, Alex C. Ruane

et al.

Nature Food, Journal Year: 2021, Volume and Issue: 2(11), P. 873 - 885

Published: Nov. 1, 2021

Language: Английский

Citations

574
Climate model projections from the Scenario Model Intercomparison Project (ScenarioMIP) of CMIP6 DOI Creative Commons
Claudia Tebaldi, Kevin Debeire, Veronika Eyring

et al.

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

Citations

476
Climate simulations: recognize the ‘hot model’ problem DOI Open Access
Zeke Hausfather, Kate Marvel, Gavin A. Schmidt

et al.

Nature, Journal Year: 2022, Volume and Issue: 605(7908), P. 26 - 29

Published: May 4, 2022

Language: Английский

Citations

354
CMIP6 Simulations With the CMCC Earth System Model (CMCC‐ESM2) DOI
Tomas Lovato, Daniele Peano, Momme Butenschön

et al.

Journal of Advances in Modeling Earth Systems, Journal Year: 2022, Volume and Issue: 14(3)

Published: Feb. 11, 2022

Abstract This article introduces the second generation CMCC Earth System Model (CMCC‐ESM2) that extends a number of marine and terrestrial biogeochemical processes with respect to its CMIP5 predecessor. In particular, land biogeochemistry was extended wider set carbon pools plant functional types, along prognostic representation nitrogen cycle. The ecosystem reshaped toward an intermediate complexity lower trophic level interactions, including interactive benthic compartment new formulation heterotrophic bacterial population. Details are provided on model setup implementation for different experiments performed as contribution sixth phase Coupled Intercomparison Project. CMCC‐ESM2 shows equilibrium climate sensitivity 3.57°C transient response 1.97°C which close CMIP6 multi‐model averages. evaluation coupled climate‐carbon in historical period against available observational datasets show consistent both physical quantities. However, sink is found be weaker than current global estimates simulated primary production slightly below satellite‐based average over recent decades. Future projections coherently prominent warming northern hemisphere intensified precipitations at high latitudes. expected ranges variability oceanic pH oxygen, well soil storage, compare favorably those assessed from other models.

Language: Английский

Citations

298
Reduced global warming from CMIP6 projections when weighting models by performance and independence DOI Creative Commons
Lukas Brunner, Angeline G. Pendergrass, Flavio Lehner

et al.

Earth System Dynamics, Journal Year: 2020, Volume and Issue: 11(4), P. 995 - 1012

Published: Nov. 13, 2020

Abstract. The sixth Coupled Model Intercomparison Project (CMIP6) constitutes the latest update on expected future climate change based a new generation of models. To extract reliable estimates warming and related uncertainties from these models, spread in their projections is often translated into probabilistic such as mean likely range. Here, we use model weighting approach, which accounts for models' historical performance several diagnostics well interdependence within CMIP6 ensemble, to calculate constrained distributions global temperature change. We investigate skill our approach perfect test, where previous-generation CMIP5 models pseudo-observations period. distribution weighted abovementioned manner with respect matching then evaluated, find increase about 17 % compared unweighted distribution. In addition, show that independence metric correctly clusters known be similar “family tree”, enables application degree inter-model dependence. apply two observational (the fifth European Centre Medium-Range Weather Forecasts Retrospective Analysis – ERA5, Modern-Era analysis Research Applications, version 2 MERRA-2), constrain under weak (SSP1-2.6) strong (SSP5-8.5) scenarios (SSP refers Shared Socioeconomic Pathways). Our results reduction projected both because some high receive systematically lower weights. end-of-century (2081–2100 relative 1995–2014) SSP5-8.5 3.7 ∘C, 4.1 ∘C without weighting; (66%) uncertainty range 3.1 4.6 equates 13 decrease spread. For SSP1-2.6, 1 (0.7 1.4 ∘C), −0.1 −24 case.

Language: Английский

Citations

265
High-resolution (1 km) Köppen-Geiger maps for 1901–2099 based on constrained CMIP6 projections DOI Creative Commons
Hylke E. Beck, Tim R. McVicar, Noemi Vergopolan

et al.

Scientific Data, Journal Year: 2023, Volume and Issue: 10(1)

Published: Oct. 23, 2023

We introduce Version 2 of our widely used 1-km Köppen-Geiger climate classification maps for historical and future conditions. The (encompassing 1901-1930, 1931-1960, 1961-1990, 1991-2020) are based on high-resolution, observation-based climatologies, while the 2041-2070 2071-2099) downscaled bias-corrected projections seven shared socio-economic pathways (SSPs). evaluated 67 models from Coupled Model Intercomparison Project phase 6 (CMIP6) kept a subset 42 with most plausible CO2-induced warming rates. estimate that 1901-1930 to 1991-2020, approximately 5% global land surface (excluding Antarctica) transitioned different major class. Furthermore, we project 1991-2020 2071-2099, will transition class under low-emissions SSP1-2.6 scenario, 8% middle-of-the-road SSP2-4.5 13% high-emissions SSP5-8.5 scenario. maps, along associated confidence estimates, underlying monthly air temperature precipitation data, sensitivity metrics CMIP6 models, can be accessed at www.gloh2o.org/koppen .

Language: Английский

Citations

207
Historical (1850–2014) Aerosol Evolution and Role on Climate Forcing Using the GISS ModelE2.1 Contribution to CMIP6 DOI Creative Commons
Susanne E. Bauer, Kostas Tsigaridis, G. Faluvegi

et al.

Journal of Advances in Modeling Earth Systems, Journal Year: 2020, Volume and Issue: 12(8)

Published: May 27, 2020

Abstract The Earth's climate is rapidly changing. Over the past centuries, aerosols, via their ability to absorb or scatter solar radiation and alter clouds, played an important role in counterbalancing some of greenhouse gas (GHG) caused global warming. multicentury anthropogenic aerosol cooling effect prevented present‐day from reaching even higher surface air temperatures subsequent more dramatic impacts. Trends concentrations optical depth show that many polluted regions such as Europe United States, precursor emissions decreased back levels 1950s. More recent polluting countries China may have reached a turning point years well, while India still follows upward trend. Here we study trends Coupled Model Intercomparison Project Phase 6 (CMIP6) simulations GISS ModelE2.1 model using fully coupled atmosphere composition configuration, including interactive gas‐phase chemistry either microphysical (MATRIX) mass‐based (One‐Moment Aerosol, OMA) module. Results whether radiative forcing already declining depends on scheme used. Using scheme, where system reacts strongly trend sulfur dioxide (SO 2 ) emissions, peak direct was 1980s, whereas simulates around 2010.

Language: Английский

Citations

194
Systematic Climate Model Biases in the Large‐Scale Patterns of Recent Sea‐Surface Temperature and Sea‐Level Pressure Change DOI Open Access
Robert C. J. Wills, Yue Dong,

Cristian Proistosecu

et al.

Geophysical Research Letters, Journal Year: 2022, Volume and Issue: 49(17)

Published: Sept. 1, 2022

Abstract Observed surface temperature trends over recent decades are characterized by (a) intensified warming in the Indo‐Pacific Warm Pool and slight cooling eastern equatorial Pacific, consistent with Walker circulation strengthening, (b) Southern Ocean cooling. In contrast, state‐of‐the‐art coupled climate models generally project enhanced weakening, warming. Here we investigate ability of 16 model large ensembles to reproduce observed sea‐surface sea‐level pressure 1979–2020 through a combination externally forced change internal variability. We find large‐scale differences between modeled that very unlikely (<5% probability) occur due variability as represented models. Disparate ratio tropical‐mean warming, which shows little multi‐decadal models, hint biases response historical forcing constitute part discrepancy.

Language: Английский

Citations

177
FaIRv2.0.0: a generalized impulse response model for climate uncertainty and future scenario exploration DOI Creative Commons
Nicholas Leach, Stuart Jenkins, Zebedee Nicholls

et al.

Geoscientific model development, Journal Year: 2021, Volume and Issue: 14(5), P. 3007 - 3036

Published: May 27, 2021

Abstract. Here we present an update to the FaIR model for use in probabilistic future climate and scenario exploration, integrated assessment, policy analysis, education. In this have focussed on identifying a minimum level of structural complexity model. The result is set six equations, five which correspond standard impulse response used greenhouse gas (GHG) metric calculations IPCC's Fifth Assessment Report, plus one additional physically motivated equation represent state-dependent feedbacks timescales each cycle. This necessary reproduce non-linearities carbon cycle apparent both Earth system models observations. These equations are transparent sufficiently simple that able be ported into tabular data analysis packages, such as Excel, increasing potential user base considerably. However, demonstrate flexible enough tuned emulate behaviour several key processes within more complex from CMIP6. exceptionally quick run, making it ideal integrating large ensembles. We apply constraint based current estimates global warming trend million-member ensemble, using constrained ensemble make scenario-dependent projections infer ranges properties system. Through these analyses, reaffirm (unlike models) not themselves intrinsically biased “hot” or “cold”: choice parameters how those selected determines response, something appears been misunderstood past. updated GHG aerosol emissions with sufficient accuracy useful wide range applications therefore could lowest-common-denominator provide consistency different contexts. fact can written down just greatly aids transparency

Language: Английский

Citations

106
Evaluating Climate Models’ Cloud Feedbacks Against Expert Judgment DOI
Mark D. Zelinka, Stephen A. Klein, Yi Qin

et al.

Journal of Geophysical Research Atmospheres, Journal Year: 2022, Volume and Issue: 127(2)

Published: Jan. 11, 2022

Abstract The persistent and growing spread in effective climate sensitivity (ECS) across global models necessitates rigorous evaluation of their cloud feedbacks. Here we evaluate several feedback components simulated 19 against benchmark values determined via an expert synthesis observational, theoretical, high‐resolution modeling studies. We find that with smallest errors relative to these generally have moderate total feedbacks (0.4–0.6 W m −2 K −1 ) ECS (3–4 K). Those largest are too large or small. Models tend achieve positive by having systematically biased high rather than a single anomalously component, vice versa. In general, better simulation mean‐state properties leads stronger but not necessarily Python code base provided herein could be applied developmental versions assess place them the context other judgment real‐time during model development.

Language: Английский

Citations

82