Role of Pacific Ocean climate in regulating runoff in the source areas of water transfer projects on the Pacific Rim

npj Climate and Atmospheric Science, Journal Year: 2024, Volume and Issue: 7(1)

Published: June 29, 2024

Abstract Over the past two decades, more frequent and intense climate events have seriously threatened operation of water transfer projects in Pacific Rim region. However, role climatic change driving runoff variations source areas these is unclear. We used tree-ring data to reconstruct changes Hanjiang River since 1580 CE representing an important area for China’s south-north project. Comparisons with hydroclimatic reconstructions southwestern United States central Chile indicated that region has experienced multiple coinciding droughts related ENSO activity. Climate simulations indicate increased likelihood drought occurrence coming decades. The combination warming-induced stresses dynamic El Niño (warming ENSO) patterns a thread urban agglomerations agricultural regions rely on along Rim.

Language: Английский

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Hemispherically symmetric strategies for stratospheric aerosol injection

Earth System Dynamics, Journal Year: 2024, Volume and Issue: 15(2), P. 191 - 213

Published: March 13, 2024

Abstract. Stratospheric aerosol injection (SAI) comes with a wide range of possible design choices, such as the location and timing injection. Different stratospheric strategies can yield different climate responses; therefore, understanding outcomes is crucial to making informed future decisions on SAI, along consideration other factors. Yet, date, there has been no systematic exploration broad SAI strategies. This limits ability determine which effects are robust across depend specific choices. study systematically explores how choice strategy affects responses in one model. Here, we introduce four hemispherically symmetric strategies, all designed maintain same global mean surface temperature: an annual at Equator (EQ), equal amounts SO2 15° N S (15N+15S), 30° (30N+30S), polar that injects 60° only during spring each hemisphere (60N+60S). We compare these more complex quantities N, S, order not temperature but also its large-scale horizontal gradients. All five simulated using version 2 Community Earth System Model middle atmosphere Whole Atmosphere Climate model, 6, atmospheric component, CESM2(WACCM6-MA), warming scenario, Shared Socioeconomic Pathway (SSP)2-4.5. find spatial distribution optical depths, efficiency, various responses. In addition, injecting subtropics produces cooling per unit injection, EQ 60N+60S cases requiring, respectively, 59 % 50 than 30N+30S case meet target. Injecting higher latitudes results larger Equator-to-pole While restore Arctic September sea ice, high-latitude effective due SAI-induced occurring preferentially latitudes. These suggest trade-offs wherein appear better or worse, depending metrics deemed important.

Language: Английский

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Injection strategy – a driver of atmospheric circulation and ozone response to stratospheric aerosol geoengineering

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(21), P. 13665 - 13684

Published: Nov. 3, 2023

Abstract. Despite offsetting global mean surface temperature, various studies demonstrated that stratospheric aerosol injection (SAI) could influence the recovery of ozone and have important impacts on tropospheric circulation, thereby potentially playing an role in modulating regional seasonal climate variability. However, so far, most assessments such approach come from model simulations which SO2 is injected only a single location or set locations. Here we use CESM2-WACCM6 SAI under comprehensive strategies achieving same temperature with different locations and/or timing injections, namely equatorial injection, annual equal amounts at 15∘ N S, 30∘ polar strategy injecting 60∘ S spring each hemisphere. We demonstrate despite result contrastingly magnitudes aerosol-induced lower warming, moistening, strengthening jets both hemispheres, changes speed residual circulation. These tend to maximise become smaller as aerosols are away Equator into subtropics higher latitudes. In conjunction differences direct radiative surface, these drive extratropical modes variability (Northern Southern Annular modes), including consequences northern winter climate, intensity tropical Walker Hadley circulations, precipitation patterns. Finally, choice also plays first-order future evolution throughout globe. Overall, our results contribute increased understanding fine interplay radiative, dynamical, chemical processes driving atmospheric circulation response lay foundation for designing optimal form basis multi-model intercomparisons.

Language: Английский

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The Choice of Baseline Period Influences the Assessments of the Outcomes of Stratospheric Aerosol Injection

Earth s Future, Journal Year: 2023, Volume and Issue: 11(8)

Published: Aug. 1, 2023

Abstract The specifics of the simulated injection choices in case stratospheric aerosol injections (SAI) are part crucial context necessary for meaningfully discussing impacts that a deployment SAI would have on planet. One main is desired amount cooling aiming to achieve. Previous simulations usually either fixed injection, resulting warming being offset, or specified one target temperature, so only dependent underlying trajectory greenhouse gases. Here, we use three sets achieving different amounts global mean surface while following middle‐of‐the‐road gas emission trajectory: scenario maintains temperatures at 1.5°C above preindustrial levels (PI), and two other scenarios which achieve additional 1.0°C 0.5°C PI. We demonstrate various scale proportionally with respect cooling, such as precipitation changes, changes Atlantic Meridional Overturning Circulation Walker Cell. also highlight importance choice baseline period when comparing responses another pathway. This analysis leads policy‐relevant discussions around concept reference altogether, what constitutes relevant, significant, change produced by SAI.

Language: Английский

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Speed of environmental change frames relative ecological risk in climate change and climate intervention scenarios

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: April 18, 2024

Abstract Stratospheric aerosol injection is a potential method of climate intervention to reduce risk as decarbonization efforts continue. However, possible ecosystem impacts from the strategic design hypothetical scenarios are poorly understood. Two recent Earth system model simulations depict policy-relevant stratospheric with similar global temperature targets, but 10-year delay in deployment. Here we show this leads distinct ecological profiles through speeds, which describe rate movement thermal conditions. On planetary scale, speeds simulation where maintains not statistically distinguishable preindustrial In contrast, rapid reduction following delayed deployment produces over land beyond either baseline or no-intervention change present policy. The area exposed threshold places different context their relative risks. Our results support discussion tradeoffs and timescales future scenario decision-making.

Language: Английский

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Kicking the can down the road: understanding the effects of delaying the deployment of stratospheric aerosol injection

Environmental Research Climate, Journal Year: 2024, Volume and Issue: 3(3), P. 035011 - 035011

Published: June 4, 2024

Abstract Climate change is a prevalent threat, and it unlikely that current mitigation efforts will be enough to avoid unwanted impacts. One potential option reduce climate impacts the use of stratospheric aerosol injection (SAI). Even if SAI ultimately deployed, might initiated only after some temperature target exceeded. The consequences such delay are assessed herein. This study compares two cases, with same global mean ∼1.5° C above preindustrial, but start dates 2035 or ‘delayed’ in 2045. We make simulations Community Earth System Model version 2 Whole Atmosphere Coupled Chemistry 6 (CESM2-WACCM6), using under SSP2-4.5 emissions pathway. find delaying deployment (relative temperature) necessitates lower net radiative forcing (−30%) thus larger sulfur dioxide rates (+20%), even surface temperatures converge, compensate for extra energy absorbed by system. Southern hemisphere ozone higher from 2050 delayed scenario, converges value later century. However, many differences between 2045 appear small during 10–25 years following start, although longer would needed assess any longer-term this model. In addition, irreversibilities tipping points triggered period increased warming may not adequately represented model could conclusion real world.

Language: Английский

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Emulating inconsistencies in stratospheric aerosol injection

Environmental Research Climate, Journal Year: 2024, Volume and Issue: 3(3), P. 035012 - 035012

Published: May 29, 2024

Abstract Stratospheric aerosol injection (SAI) would involve the addition of sulfate aerosols in stratosphere to reflect part incoming solar radiation, thereby cooling climate. Studies trying explore impacts SAI have often focused on idealized scenarios without explicitly introducing what we call ‘inconsistencies’ a deployment. A concern discussed is happen climate system after an abrupt termination its deployment, whether inadvertent or deliberate. However, there much wider range plausible inconsistencies deployment than that should be evaluated better understand associated risks. In this work, simulate few representative pre-existing scenario: termination, decade-long gradual phase-out, and 1 year 2 temporary interruptions After examining their impacts, use these simulations train emulator, project global mean temperature response for broader set Our work highlights capacity finite simulated include inform emulator capable expanding space one might want far more quickly efficiently.

Language: Английский

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Insights into Surface Ozone Variability in India (1980-2014) through CMIP6 Model Analysis

Atmospheric Environment, Journal Year: 2025, Volume and Issue: unknown, P. 121180 - 121180

Published: March 1, 2025

Language: Английский

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The Potential of Stratospheric Aerosol Injection to Reduce the Climatic Risks of Explosive Volcanic Eruptions

Geophysical Research Letters, Journal Year: 2024, Volume and Issue: 51(8)

Published: April 22, 2024

Abstract Sulfur‐rich volcanic eruptions happen sporadically. If Stratospheric Aerosol Injection (SAI) were to be deployed, it is likely that explosive would during such a deployment. Here we use an ensemble of Earth System Model simulations show how changing the injection strategy post‐eruption could used reduce climate risks large eruption; are also modified even without any change strategy. For medium‐size eruption (10 Tg‐SO 2 ) comparable SAI rate, volcanic‐induced cooling reduced if occurs under SAI, especially artificial sulfur dioxide injections immediately suspended. Alternatively, suspending only in hemisphere and continuing opposite shifts precipitation tropical belt thus mitigate eruption‐induced drought. Finally, for much larger than deployment, changes have minimal effect.

Language: Английский

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Highlighting the Impact of Anthropogenic OCS Emissions on the Stratospheric Sulfur Budget With In Situ Observations

Journal of Geophysical Research Atmospheres, Journal Year: 2025, Volume and Issue: 130(9)

Published: May 6, 2025

Abstract Carbonyl sulfide (OCS) is an important atmospheric sulfur species that plays a dominant role in the formation of (nonvolcanic) stratospheric sulfate aerosol middle stratosphere. Major uncertainties surface sources and sinks inconsistent model representation vertical transport limit understanding OCS distribution, particularly sparsely sampled upper atmosphere. During 2022 Asian Summer Monsoon Chemical CLimate Impact Project (ACCLIP) campaign, situ measurements Upper Troposphere Lower Stratosphere (UTLS) at eastern edge summer monsoon anticyclone (ASM), showed significant enhancements (>750 ppt) near tropopause from convectively influenced air parcels. Here, we compare these novel UTLS with long‐term satellite observations regional to broaden trends its by ASM. Trajectory analysis identifies northern China as main source region for deep convective lofting OCS‐enriched parcels demonstrates ASM entrainment UTLS, allowing evaluation global predictions OCS's influence. The ACCLIP data set provides vital validation limited vertically resolved anthropogenic emissions, which serves enhance our budget.

Language: Английский

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