Global warming in the pipeline

Oxford Open Climate Change, Год журнала: 2023, Номер 3(1)

Опубликована: Янв. 1, 2023

Abstract Improved knowledge of glacial-to-interglacial global temperature change yields Charney (fast-feedback) equilibrium climate sensitivity 1.2 ± 0.3°C (2σ) per W/m2, which is 4.8°C 1.2°C for doubled CO2. Consistent analysis over the full Cenozoic era—including ‘slow’ feedbacks by ice sheets and trace gases—supports this implies that CO2 was 300–350 ppm in Pliocene about 450 at transition to a nearly ice-free planet, exposing unrealistic lethargy sheet models. Equilibrium warming today’s GHG amount 10°C, reduced 8°C human-made aerosols. not ‘committed’ warming; rapid phaseout emissions would prevent most from occurring. However, decline aerosol since 2010 should increase 1970–2010 rate 0.18°C decade post-2010 least 0.27°C decade. Thus, under present geopolitical approach emissions, will exceed 1.5°C 2020s 2°C before 2050. Impacts on people nature accelerate as increases hydrologic (weather) extremes. The enormity consequences demands return Holocene-level temperature. Required actions include: (1) increasing price accompanied development abundant, affordable, dispatchable clean energy, (2) East-West cooperation way accommodates developing world needs, (3) intervention with Earth’s radiation imbalance phase down massive ‘geo-transformation’ climate. Current political crises an opportunity reset, especially if young can grasp their situation.

Язык: Английский

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Opportunistic experiments to constrain aerosol effective radiative forcing

Atmospheric chemistry and physics, Год журнала: 2022, Номер 22(1), С. 641 - 674

Опубликована: Янв. 17, 2022

Aerosol-cloud interactions (ACIs) are considered to be the most uncertain driver of present-day radiative forcing due human activities. The nonlinearity cloud-state changes aerosol perturbations make it challenging attribute causality in observed relationships forcing. Using correlations infer can when meteorological variability also drives both and cloud independently. Natural anthropogenic from well-defined sources provide "opportunistic experiments" (also known as natural experiments) investigate ACI cases where may more confidently inferred. These cover a wide range locations spatiotemporal scales, including point such volcanic eruptions or industrial sources, plumes biomass burning forest fires, tracks individual ships shipping corridors. We review different experimental conditions conduct synthesis available satellite datasets field campaigns place these opportunistic experiments on common footing, facilitating new insights clearer understanding key uncertainties Cloud albedo strongly sensitive background conditions. Strong liquid water path increases largely ruled out by averaging across experiments. Opportunistic have significantly improved process-level ACI, but remains unclear how reliably found scaled global level, thus demonstrating need for deeper investigation order improve assessments climate change.

Язык: Английский

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Machine learning reveals climate forcing from aerosols is dominated by increased cloud cover

Nature Geoscience, Год журнала: 2022, Номер 15(8), С. 609 - 614

Опубликована: Авг. 1, 2022

Язык: Английский

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Abrupt reduction in shipping emission as an inadvertent geoengineering termination shock produces substantial radiative warming

Communications Earth & Environment, Год журнала: 2024, Номер 5(1)

Опубликована: Май 30, 2024

Abstract Human activities affect the Earth’s climate through modifying composition of atmosphere, which then creates radiative forcing that drives change. The warming effect anthropogenic greenhouse gases has been partially balanced by cooling aerosols. In 2020, fuel regulations abruptly reduced emission sulfur dioxide from international shipping about 80% and created an inadvertent geoengineering termination shock with global impact. Here we estimate regulation leads to a $$+0.2\pm 0.11$$ +0.2±0.11 Wm −2 averaged over ocean. amount could lead doubling (or more) rate in 2020 s compared since 1980 strong spatiotemporal heterogeneity. is consistent recent observed 2023 expected make anomalously warm. equivalent magnitude measured increase planetary heat uptake 2020. also hemispheric contrast, important implications for precipitation pattern changes. Our result suggests marine cloud brightening may be viable method temporarily its unique challenges due inherent

Язык: Английский

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

Science Advances, Год журнала: 2024, Номер 10(12)

Опубликована: Март 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.

Язык: Английский

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

Nature Geoscience, Год журнала: 2024, Номер 17(5), С. 404 - 410

Опубликована: Апрель 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.

Язык: Английский

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Invisible ship tracks show large cloud sensitivity to aerosol

Nature, Год журнала: 2022, Номер 610(7930), С. 101 - 106

Опубликована: Окт. 5, 2022

Abstract Cloud reflectivity is sensitive to atmospheric aerosol concentrations because aerosols provide the condensation nuclei on which water condenses 1 . Increased due human activity affect droplet number concentration, liquid and cloud fraction 2 , but these changes are subject large uncertainties 3 Ship tracks, long lines of polluted clouds that visible in satellite images, one main tools for quantifying aerosol–cloud interactions 4 However, only a small by shipping show ship tracks 5,6 Here we even when no emissions change properties substantially. We develop new method quantify effect all clouds, showing increase more positive response there tracks. directly detect shipping-induced property trade cumulus regions Atlantic, known display almost Our results indicate previous studies were suffering from selection biases focusing imagery. The strong path find translates larger cooling climate, potentially masking higher climate sensitivity than observed temperature trends would otherwise suggest.

Язык: Английский

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Albedo susceptibility of northeastern Pacific stratocumulus: the role of covarying meteorological conditions

Atmospheric chemistry and physics, Год журнала: 2022, Номер 22(2), С. 861 - 880

Опубликована: Янв. 19, 2022

Abstract. Quantification of the radiative adjustment marine low clouds to aerosol perturbations, regionally and globally, remains largest source uncertainty in assessing current future climate. One important steps towards quantifying role modifying cloud properties is quantify susceptibility albedo liquid water path (LWP) perturbations droplet number concentration (Nd). We use 10 years spaceborne observations from polar-orbiting Aqua satellite Nd over northeast (NE) Pacific stratocumulus (Sc) region. Mutual information analysis reveals a dominating control state (e.g., LWP Nd) on low-cloud susceptibility, relative meteorological states that drive these states. Through LWP–Nd space decomposition susceptibilities, we show clear separation among regimes (brightening or darkening), consistent with previously established mechanisms through which modulates properties. These include (i) thin non-precipitating (LWP < 55 g m−2) exhibit brightening (occurring 37 % time), corresponding Twomey effect; (ii) thicker clouds, entrainment-driven negative adjustments manifest as darkening regime (36 time); (iii) another (22 time) consisting mostly precipitating precipitation-suppression positive adjustments. Overall, find an annual-mean regional potential 20.8±2.68 W m−2 ln(Nd)−1, despite overall for stratocumulus, owing high occurrence Twomey–brightening regime. Over NE Pacific, seasonal covariabilities factors related large-scale circulation are found play grouping conditions favorable each When considering covarying conditions, our results indicate northeastern strongest occur most frequently within shallow boundary layers cool ocean surface stable atmosphere dry free troposphere above. Clouds associated deep atmospheric instability not strong warm enough produce frequent precipitation. Cloud warm-rain suppression preferably either under unstable humid free-tropospheric co-occur surface.

Язык: Английский

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Shipping regulations lead to large reduction in cloud perturbations

Proceedings of the National Academy of Sciences, Год журнала: 2022, Номер 119(41)

Опубликована: Окт. 3, 2022

Global shipping accounts for 13% of global emissions SO 2 , which, once oxidized to sulfate aerosol, acts cool the planet both directly by scattering sunlight and indirectly increasing albedo clouds. This cooling due aerosol offsets some warming effect greenhouse gasses is largest uncertainty in determining change Earth’s radiative balance human activity. Ship tracks—the visible manifestation indirect ship on clouds as quasi-linear features—have long provided an opportunity quantify these effects. However, they have been arduous catalog typically studied only particular regions short periods time. Using a machine-learning algorithm automate their detection we more than 1 million tracks provide climatology. We use this investigate stringent fuel regulations introduced International Maritime Organization 2020 prevalence since then, while accounting disruption commerce caused COVID-19. find marked, but clearly nonlinear, decline globally: An 80% reduction x causes 25% number detected.

Язык: Английский

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Large contribution of fossil-derived components to aqueous secondary organic aerosols in China

Nature Communications, Год журнала: 2022, Номер 13(1)

Опубликована: Авг. 31, 2022

Incomplete understanding of the sources secondary organic aerosol (SOA) leads to large uncertainty in both air quality management and climate change assessment. Chemical reactions occurring atmospheric aqueous phase represent an important source SOA mass, yet, effects anthropogenic emissions on (aqSOA) are not well constrained. Here we use compound-specific dual-carbon isotopic fingerprints (δ13C Δ14C) dominant aqSOA molecules, such as oxalic acid, track precursor formation mechanisms aqSOA. Substantial stable carbon isotope fractionation molecules provides robust evidence for extensive aqueous-phase processing. Contrary paradigm that these compounds largely biogenic, radiocarbon-based apportionments show fossil precursors produced over one-half molecules. Large fractions fossil-derived contribute substantially total water-soluble load hence impact projections radiative forcing. Our findings reveal importance with quality.

Язык: Английский

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