Robust evidence for reversal of the trend in aerosol effective climate forcing

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(18), P. 12221 - 12239

Published: Sept. 21, 2022

Abstract. Anthropogenic aerosols exert a cooling influence that offsets part of the greenhouse gas warming. Due to their short tropospheric lifetime only several days, aerosol forcing responds quickly emissions. Here, we present and discuss evolution since 2000. There are multiple lines evidence allow us robustly conclude anthropogenic effective radiative (ERF) – both aerosol–radiation interactions (ERFari) aerosol–cloud (ERFaci) has become less negative globally, i.e. trend in changed sign from positive. Bottom-up inventories show primary precursor emissions declined most regions world; observations related burden declining trends, particular fine-mode particles make up aerosols; satellite retrievals cloud droplet numbers trends with declines consistent these sign, as do top-of-atmosphere radiation. Climate model results, including revised set is constrained by ocean heat content magnitude for positive relative year 2000 due reduced effects. This reduction leads an acceleration climate change, increase 0.1 0.3 W m−2, 12 % total 2019 compared 1750 according Intergovernmental Panel on Change (IPCC).

Language: Английский

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Artificial intelligence for geoscience: Progress, challenges and perspectives

The Innovation, Journal Year: 2024, Volume and Issue: 5(5), P. 100691 - 100691

Published: Aug. 23, 2024

Public summary•What does AI bring to geoscience? has been accelerating and deepening our understanding of Earth Systems in an unprecedented way, including the atmosphere, lithosphere, hydrosphere, cryosphere, biosphere, anthroposphere interactions between spheres.•What are noteworthy challenges As we embrace huge potential geoscience, several arise reliability interpretability, ethical issues, data security, high demand cost.•What is future The synergy traditional principles modern AI-driven techniques holds immense promise will shape trajectory geoscience upcoming years.AbstractThis paper explores evolution geoscientific inquiry, tracing progression from physics-based models data-driven approaches facilitated by significant advancements artificial intelligence (AI) collection techniques. Traditional models, which grounded physical numerical frameworks, provide robust explanations explicitly reconstructing underlying processes. However, their limitations comprehensively capturing Earth's complexities uncertainties pose optimization real-world applicability. In contrast, contemporary particularly those utilizing machine learning (ML) deep (DL), leverage extensive glean insights without requiring exhaustive theoretical knowledge. ML have shown addressing science-related questions. Nevertheless, such as scarcity, computational demands, privacy concerns, "black-box" nature hinder seamless integration into geoscience. methodologies hybrid presents alternative paradigm. These incorporate domain knowledge guide methodologies, demonstrate enhanced efficiency performance with reduced training requirements. This review provides a comprehensive overview research paradigms, emphasizing untapped opportunities at intersection advanced It examines major showcases advances large-scale discusses prospects that landscape outlines dynamic field ripe possibilities, poised unlock new understandings further advance exploration.Graphical abstract

Language: Английский

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Physical science research needed to evaluate the viability and risks of marine cloud brightening

Science Advances, Journal Year: 2024, Volume and Issue: 10(12)

Published: March 20, 2024

Marine cloud brightening (MCB) is the deliberate injection of aerosol particles into shallow marine clouds to increase their reflection solar radiation and reduce amount energy absorbed by climate system. From physical science perspective, consensus a broad international group scientists that viability MCB will ultimately depend on whether observations models can robustly assess scale-up local-to-global in today's identify strategies ensure an equitable geographical distribution benefits risks associated with projected regional changes temperature precipitation. To address knowledge gaps required societal implications MCB, we propose substantial targeted program research-field laboratory experiments, monitoring, numerical modeling across range scales.

Language: Английский

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Substantial cooling effect from aerosol-induced increase in tropical marine cloud cover

Nature Geoscience, Journal Year: 2024, Volume and Issue: 17(5), P. 404 - 410

Published: April 11, 2024

Abstract With global warming currently standing at approximately +1.2 °C since pre-industrial times, climate change is a pressing issue. Marine cloud brightening one proposed method to tackle through injecting aerosols into marine clouds enhance their reflectivity and thereby planetary albedo. However, because it unclear how influence clouds, especially cover, both projections the effectiveness of remain uncertain. Here we use satellite observations volcanic eruptions in Hawaii quantify aerosol fingerprint on tropical clouds. We observe large enhancement reflected sunlight, mainly due an aerosol-induced increase cover. This observed strong negative forcing suggests that current level driven by weaker net radiative than previously thought, arising from competing effects greenhouse gases aerosols. implies greater sensitivity Earth’s therefore larger response rising gas concentrations reductions atmospheric air quality measures. our findings also indicate mitigation via plausible most effective humid stable conditions tropics where solar radiation strong.

Language: Английский

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Assessing effective radiative forcing from aerosol–cloud interactions over the global ocean

Proceedings of the National Academy of Sciences, Journal Year: 2022, Volume and Issue: 119(46)

Published: Nov. 7, 2022

How clouds respond to anthropogenic sulfate aerosols is one of the largest sources uncertainty in radiative forcing climate over industrial era. This limits our ability predict equilibrium sensitivity (ECS)-the global warming following a doubling atmospheric CO2. Here, we use satellite observations quantify relationships between and low-level while carefully controlling for meteorology. We then combine with estimates change concentration since about 1850 constrain associated forcing. estimate that cloud-mediated from [Formula: see text] W m-2 ocean (95% confidence). constraint implies ECS likely 2.9 4.5 K (66% Our results indicate aerosol less uncertain probably larger than ranges proposed by recent assessments.

Language: Английский

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Reversed asymmetric warming of sub-diurnal temperature over land during recent decades

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: Nov. 8, 2023

Abstract In the latter half of twentieth century, a significant climate phenomenon “diurnal asymmetric warming” emerged, wherein global land surface temperatures increased more rapidly during night than day. However, recent episodes brightening and regional droughts heatwaves have brought notable alterations to this warming trend. Here, we re-evaluate sub-diurnal temperature patterns, revealing substantial increase in rates daily maximum (T max ), while minimum remained relatively stable. This shift has resulted reversal diurnal trend, expanding range over decades. The intensified T is attributed widespread reduction cloud cover, which led solar irradiance at surface. Our findings underscore urgent need for enhanced scrutiny trends their implications wider earth system.

Language: Английский

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Observational evidence of strong forcing from aerosol effect on low cloud coverage

Science Advances, Journal Year: 2023, Volume and Issue: 9(45)

Published: Nov. 8, 2023

Aerosols cool Earth's climate indirectly by increasing low cloud brightness and their coverage (Cf), constituting the aerosol indirect forcing (AIF). The partially offsets greenhouse warming positively correlates with sensitivity. However, it remains highly uncertain. Here, we show direct observational evidence for strong from Cf adjustment to increased aerosols weak liquid water path adjustment. We estimate that drives between 52% 300% of additional Twomey effect over ocean a total AIF -1.1 ± 0.8 W m-2. follows power law as function background droplet number concentration, Nd. It thus depends on time location is stronger when Nd low. only increases substantially clouds start drizzle, suggesting role aerosol-precipitation interactions. Our findings highlight key process reducing uncertainty future projections.

Language: Английский

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Climate intervention using marine cloud brightening (MCB) compared with stratospheric aerosol injection (SAI) in the UKESM1 climate model

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(24), P. 15305 - 15324

Published: Dec. 14, 2023

Abstract. The difficulties in using conventional mitigation techniques to maintain global-mean temperatures well below 2 ∘C compared with pre-industrial levels have been documented, leading so-called “climate intervention” or “geoengineering” research whereby the planetary albedo is increased counterbalance global warming and ameliorate some impacts of climate change. In scientific literature, most prominent intervention proposal that stratospheric aerosol injection (SAI), although proposals for marine cloud brightening (MCB) also received considerable attention. this study, we design a new MCB experiment (G6MCB) UKESM1 Earth-system model which follows same baseline cooling scenarios as well-documented G6sulfur SAI scenario developed by Geoengineering Model Intercomparison Project (GeoMIP), compare results from G6MCB those G6sulfur. deployment strategy used injects sea-salt into four cloudy areas eastern Pacific. This appears capable delivering radiative forcing up −1 W m−2 MCB, but at higher rates, much effect found derive direct interaction injected aerosols solar radiation, i.e. sky (MSB). show while can achieve its target terms reducing high-end moderate levels, there are several side effects. Some common SAI, including overcooling tropics residual middle high latitudes. Other effects specific choice targeted regions include changes monsoon precipitation, year-round increases precipitation over Australia maritime continent, sea-level rise around western continent; these all consistent permanent very strong La Niña-like response being induced G6MCB. emphasize attention needs be given oceanic feedbacks spatially inhomogeneous forcings. It should stressed extremely dependent upon chosen deployment. As demonstrated development strategies multiple temperature targets change, further work required models obtain robust understanding practical scope, limitations, pitfalls any proposed

Language: Английский

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The significance of volcanic ash in Greenland ice cores during the Common Era

Quaternary Science Reviews, Journal Year: 2023, Volume and Issue: 301, P. 107936 - 107936

Published: Jan. 10, 2023

Polar ice cores provide long, continuous and well-dated records of past volcanism have contributed significantly to our understanding volcanic impacts on climate society. Sulphate aerosols deposited in the are essential for determining effective radiative forcing potential eruptions, but calculations improved with knowledge eruption source parameters. Only co-deposition ash can presently confirm eruption. Here we review current state regarding representation Common Era from Greenland consider what tephras reveal about ice. We augment published record a large dataset previously unreported tephras, result programme targeted sampling guided by microparticle that allow us home tephra layers variable temporal relationships sulphate aerosol deposition. In addition revealing extensive region disperses Greenland, explores first time some insights provided such as magma type style. characteristics eruptions associated varying degrees responses find strongest tends be those producing mafic intermediate tephra, phreatomagmatic processes commonly involved. The frequent occurrence multiple these instances may also play role accentuating response. note consistencies timing particulate fallout Icelandic (synchronous) Alaskan (ash before sulphates) regions, greater delays (one or more years) stratospheric transport tropical eruptions. outline remaining avenues research ice-core promise throw light processes, including volatile release transport, well frequency impact small-to-moderate advocate integration wide-ranging towards better volcano-climate relationships.

Language: Английский

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Stratocumulus adjustments to aerosol perturbations disentangled with a causal approach

npj Climate and Atmospheric Science, Journal Year: 2023, Volume and Issue: 6(1)

Published: Aug. 29, 2023

Abstract A large fraction of the uncertainty around future global warming is due to cooling effect aerosol-liquid cloud interactions, and in particular elusive sign liquid water path (LWP) adjustments aerosol perturbations. To quantify this adjustment, we propose a causal approach that combines physical knowledge form graph with geostationary satellite observations stratocumulus clouds. This allows us remove confounding influences from large-scale meteorology disentangle counteracting processes (cloud-top entrainment enhancement precipitation suppression perturbations) on different timescales. results weak LWP are time-dependent (first positive then negative) meteorological regime-dependent. More importantly, reveals failing account for covariations droplet sizes depth, which are, respectively, mediator confounder influences, leads an overly negative aerosol-induced response. would result underestimation influence aerosol-cloud interactions.

Language: Английский

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