Earth beyond six of nine planetary boundaries

Science Advances, Journal Year: 2023, Volume and Issue: 9(37)

Published: Sept. 13, 2023

This planetary boundaries framework update finds that six of the nine are transgressed, suggesting Earth is now well outside safe operating space for humanity. Ocean acidification close to being breached, while aerosol loading regionally exceeds boundary. Stratospheric ozone levels have slightly recovered. The transgression level has increased all earlier identified as overstepped. As primary production drives system biosphere functions, human appropriation net proposed a control variable functional integrity. boundary also transgressed. modeling different climate and land change illustrates these anthropogenic impacts on must be considered in systemic context.

Language: Английский

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The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018

Atmospheric Environment, Journal Year: 2020, Volume and Issue: 244, P. 117834 - 117834

Published: Sept. 3, 2020

Language: Английский

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An Assessment of Earth's Climate Sensitivity Using Multiple Lines of Evidence

Reviews of Geophysics, Journal Year: 2020, Volume and Issue: 58(4)

Published: July 22, 2020

We assess evidence relevant to Earth's equilibrium climate sensitivity per doubling of atmospheric CO2, characterized by an effective S. This includes feedback process understanding, the historical record, and paleoclimate record. An S value lower than 2 K is difficult reconcile with any three lines evidence. The amount cooling during Last Glacial Maximum provides strong against values greater 4.5 K. Other in combination also show that this relatively unlikely. use a Bayesian approach produce probability density function (PDF) for given all evidence, including tests robustness difficult-to-quantify uncertainties different priors. 66% range 2.6–3.9 our Baseline calculation remains within 2.3–4.5 under tests; corresponding 5–95% ranges are 2.3–4.7 K, bounded 2.0–5.7 (although such high-confidence should be regarded more cautiously). indicates stronger constraint on reported past assessments, lifting low end range. narrowing occurs because agree judged largely independent confidence understanding processes combining identify promising avenues further S, particular using comprehensive models address limitations traditional forcing-feedback paradigm interpreting changes.

Language: Английский

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Bounding global aerosol radiative forcing of climate change

Published: March 9, 2020

<p>Aerosol radiative forcing plays an important role in the attribution of past climate changes, estimates future allowable carbon emissions, and assessment potential geoengineering solutions. Substantial progress made over 40 years observing, understanding, modelling aerosol processes helped quantify forcing, but uncertainties remain large.</p><p>In spring 2018, under auspices World Climate Research Programme's Grand Science Challenge on Clouds, Circulation Sensitivity, thirty-six experts gathered to take a fresh comprehensive look at present understanding identify prospects for some most pressing open questions. The outcome that meeting is review paper, Bellouin et al. (2019), accepted publication Reviews Geophysics. This provides new range industrial era based multiple, traceable arguable lines evidence, including approaches, theoretical considerations, observations. A substantial achievement focus evidence rather than survey results or expert judgement, make questions much more specific.</p><p>This talk will key messages arguments work show promise improving quantification forcing.</p>

Language: Английский

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Effective radiative forcing and adjustments in CMIP6 models

Atmospheric chemistry and physics, Journal Year: 2020, Volume and Issue: 20(16), P. 9591 - 9618

Published: Aug. 17, 2020

Abstract. The effective radiative forcing, which includes the instantaneous forcing plus adjustments from atmosphere and surface, has emerged as key metric of evaluating human natural influence on climate. We evaluate in 17 contemporary climate models that are participating Coupled Model Intercomparison Project (CMIP6) have contributed to Radiative Forcing (RFMIP). Present-day (2014) global-mean anthropogenic relative pre-industrial (1850) levels stands at 2.00 (±0.23) W m−2, comprised 1.81 (±0.09) m−2 CO2, 1.08 (± 0.21) other well-mixed greenhouse gases, −1.01 0.23) aerosols −0.09 (±0.13) land use change. Quoted uncertainties 1 standard deviation across model best estimates, 90 % confidence reported forcings, due internal variability, is typically within 0.1 m−2. majority remaining 0.21 likely be ozone. In most cases, largest contributors spread (ERF) (IRF) cloud responses, particularly aerosol–cloud interactions aerosol forcing. As determined previous studies, cancellation tropospheric surface means stratospherically adjusted approximately equal ERF for gas but not aerosols, consequentially, total. ranges −0.63 −1.37 exhibiting a less negative mean narrower range compared 10 CMIP5 models. 4×CO2 also narrowed CMIP6 13 Aerosol uncorrelated with sensitivity. Therefore, there no evidence suggest increasing sensitivity models, related high-sensitivity consequence stronger present-day little modelling groups systematically tuning or recreate observed historical warming.

Language: Английский

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Direct radiative effects of airborne microplastics

Nature, Journal Year: 2021, Volume and Issue: 598(7881), P. 462 - 467

Published: Oct. 20, 2021

Language: Английский

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Emergent constraints on transient climate response (TCR) and equilibrium climate sensitivity (ECS) from historical warming in CMIP5 and CMIP6 models

Earth System Dynamics, Journal Year: 2020, Volume and Issue: 11(3), P. 737 - 750

Published: Aug. 17, 2020

Abstract. Climate sensitivity to CO2 remains the key uncertainty in projections of future climate change. Transient response (TCR) is metric temperature that most relevant warming next few decades and contributes biggest estimates carbon budgets consistent with Paris targets. Equilibrium (ECS) vital for understanding longer-term change stabilisation In IPCC 5th Assessment Report (AR5), stated “likely” ranges (16 %–84 % confidence) TCR (1.0–2.5 K) ECS (1.5–4.5 were broadly ensemble CMIP5 Earth system models (ESMs) available at time. However, many latest CMIP6 ESMs have larger sensitivities, 5 34 having values above 2.5 K an mean 2.0±0.4 K. Even starker, 12 value 4.5 On face it, these ESM results suggest likely may need revising upwards, which would cast further doubt on feasibility Here we show rather than increasing sensitivity, help constrain range 1.3–2.1 K, a central estimate 1.68 We reach this conclusion through emergent constraint approach relates linearly global from 1975 onwards. This period when signal-to-noise ratio net radiative forcing increases strongly, so uncertainties aerosol become progressively less problematic. find apply same method models. Our constraints are good agreement other recent studies analysed CMIP ensembles. The relationship between post-1975 trend direct also non-linear. able derive 1.9–3.4 by assuming underlying based two-box energy balance model. Despite some methodological differences; previously published derived trends 2005. seem be part growing consensus amongst applied different model ensembles aspects record warming.

Language: Английский

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The COVID-19 lockdowns: a window into the Earth System

Nature Reviews Earth & Environment, Journal Year: 2020, Volume and Issue: 1(9), P. 470 - 481

Published: July 29, 2020

Restrictions to reduce human interaction have helped avoid greater suffering and death from the COVID-19 pandemic, but also created socioeconomic hardship. This disruption is unprecedented in modern era of global observing networks, pervasive sensing large-scale tracking mobility behaviour, creating a unique test bed for understanding Earth System. In this Perspective, we hypothesize immediate long-term System responses along two multidisciplinary cascades: energy, emissions, climate air quality; poverty, globalization, food biodiversity. While short-term impacts are dominated by direct effects arising reduced activity, longer-lasting likely result cascading economic recession on green investment behaviour. These offer opportunity novel insight, particularly with careful deployment targeted data collection, coordinated model experiments solution-oriented randomized controlled trials, during after pandemic. The pandemic has caused substantial impact. Perspective provides insight into environmental documenting how it offers an better understand

Language: Английский

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Validation of GRASP algorithm product from POLDER/PARASOL data and assessment of multi-angular polarimetry potential for aerosol monitoring

Earth system science data, Journal Year: 2020, Volume and Issue: 12(4), P. 3573 - 3620

Published: Dec. 22, 2020

Abstract. Proven by multiple theoretical and practical studies, multi-angular spectral polarimetry is ideal for comprehensive retrieval of properties aerosols. Furthermore, a large number advanced space polarimeters have been launched recently or planned to be deployed in the coming few years (Dubovik et al., 2019). Nevertheless, at present, utilization aerosol products from rather limited, due relatively small polarimetric compared photometric observations, as well challenges making full use extensive information content available these complex observations. Indeed, while recent several new algorithms developed provide enhanced retrievals satellite polarimetry, value yet remains proven. In this regard, paper presents analysis obtained Generalized Retrieval Atmosphere Surface Properties (GRASP) algorithm POLDER/PARASOL After about decade development, GRASP has adapted operational processing observations released. These updated PARASOL/GRASP are publicly (e.g., http://www.icare.univ-lille.fr, last access: 16 October 2018, http://www.grasp-open.com/products/, 28 March 2020); dataset used current study registered under https://doi.org/10.5281/zenodo.3887265 (Chen 2020). The objective comprehensively evaluate First, validation entire 2005–2013 archive was conducted comparing ground-based Aerosol Robotic Network (AERONET) data. subjects optical depth (AOD), absorption (AAOD) single-scattering albedo (SSA) six wavelengths, Ångström exponent (AE), fine-mode AOD (AODF) coarse-mode (AODC) interpolated reference wavelength 550 nm. Second, an inter-comparison with PARASOL/Operational, MODIS Dark Target (DT), Deep Blue (DB) Multi-Angle Implementation Atmospheric Correction (MAIAC) year 2008 performed. Over land both data validations inter-comparisons were separately different surface types, discriminated bins normalized difference vegetation index (NDVI): < 0.2, 0.2 ≤ 0.4, 0.4 0.6, ≥ 0.6. Three analyzed: GRASP/HP (“High Precision”), Optimized Models. consistent but using assumptions modeling accuracies atmospheric radiative transfer (RT) calculations. Specifically, when there direct size distribution refraction. When GRASP/Models, approximated mixture prescribed components, each their own fixed properties, only concentrations those components retrieved. employs most accurate RT calculations, GRASP/Optimized GRASP/Models optimized achieve best trade-off between accuracy speed. all three options, underlying reflectance retrieved simultaneously calculations performed “online” during retrieval. All results show solid quality characteristics. retrievals, however, provided products, e.g., (550 nm) unbiased highest correlation (R ∼ 0.92) fraction (∼ 55.3 %) satisfying requirements Global Climate Observing System (GCOS) AERONET non-negligible positive bias 0.07) low (< 0.2). On other hand, detailed microphysical characteristics (AE, AODF, AODC, SSA, etc.) correlate generally better than do GRASP/Models. Overall, demonstrates high versus AERONET. Evidently, approach more total AOD, limited models used. comparative showed that, based on against AERONET, product similar sometimes higher products. good agreement over ocean. land, especially bright surfaces, degrades differences increase. characteristics, such AE, AODF AODC PARASOL/GRASP, reliable, land. global robust agreement, though some patterns tendencies observed. ocean, PARASOL/Models MODIS/DT agree coefficient 0.92. lower, ranging 0.76 0.85. There no significant offset; surfaces tend values smaller moderate AODs. Seasonal means suggest that biomass burning loading central Africa dust Taklamakan Desert, less northern Sahara. It noticeable also sites somewhat higher, suggesting work rest globe. One potential reasons may general, rely climatology retrievals. shows like POLDER least comparable single-viewing MODIS-like imagers. At same time, AE), additional parameters AAOD SSA.

Language: Английский

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Biomass burning aerosols in most climate models are too absorbing

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: Jan. 12, 2021

Uncertainty in the representation of biomass burning (BB) aerosol composition and optical properties climate models contributes to a range modeled effects on incoming solar radiation. Depending model, top-of-the-atmosphere BB effect can from cooling warming. By relating absorption relative extinction carbonaceous 12 observational datasets nine state-of-the-art Earth system models/chemical transport models, we identify varying degrees overestimation absorptivity by these models. Modifications refractive index, size, mixing state improve Community Atmosphere Model version 5 (CAM5) agreement with observations, leading global change direct radiative -0.07 W m-2, regional changes -2 m-2 (Africa) -0.5 (South America/Temperate). Our findings suggest that current less warming than previously thought, largely due treatments state.

Language: Английский

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