Radiative and climate impacts of a large volcanic eruption during  stratospheric sulfur geoengineering

Abstract. Both explosive volcanic eruptions, which emit sulfur dioxide into the stratosphere, and stratospheric geoengineering via sulfur injections can potentially cool the climate by increasing the amount of scattering particles in the atmosphere. Here we employ a global aerosol-climate model and an Earth system model to study the radiative and climate changes occurring after an erupting volcano during solar radiation management (SRM). According to our simulations the radiative impacts of the eruption and SRM are not additive and the radiative effects and climate changes occurring after the eruption depend strongly on whether SRM is continued or suspended after the eruption. In the former case, the peak burden of the additional stratospheric sulfate as well as changes in global mean precipitation are fairly similar regardless of whether the eruption takes place in a SRM or non-SRM world. However, the maximum increase in the global mean radiative forcing caused by the eruption is approximately 21 % lower compared to a case when the eruption occurs in an unperturbed atmosphere. In addition, the recovery of the stratospheric sulfur burden and radiative forcing is significantly faster after the eruption, because the eruption during the SRM leads to a smaller number and larger sulfate particles compared to the eruption in a non-SRM world. On the other hand, if SRM is suspended immediately after the eruption, the peak increase in global forcing caused by the eruption is about 32 % lower compared to a corresponding eruption into a clean background atmosphere. In this simulation, only about one-third of the global ensemble-mean cooling occurs after the eruption, compared to that occurring after an eruption under unperturbed atmospheric conditions. Furthermore, the global cooling signal is seen only for the 12 months after the eruption in the former scenario compared to over 40 months in the latter. In terms of global precipitation rate, we obtain a 36 % smaller decrease in the first year after the eruption and again a clearly faster recovery in the concurrent eruption and SRM scenario, which is suspended after the eruption. We also found that an explosive eruption could lead to significantly different regional climate responses depending on whether it takes place during geoengineering or into an unperturbed background atmosphere. Our results imply that observations from previous large eruptions, such as Mount Pinatubo in 1991, are not directly applicable when estimating the potential consequences of a volcanic eruption during stratospheric geoengineering.

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Radiative and climate impacts of a large volcanic eruption during stratospheric sulfur geoengineering

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-21837-2015 ◽

2015 ◽

Vol 15 (15) ◽

pp. 21837-21881 ◽

Cited By ~ 2

Author(s):

A. Laakso ◽

H. Kokkola ◽

A.-I. Partanen ◽

U. Niemeier ◽

C. Timmreck ◽

...

Keyword(s):

Volcanic Eruption ◽

Climate Model ◽

Regional Climate ◽

Volcanic Eruptions ◽

Stratospheric Aerosol ◽

Climate Impacts ◽

Solar Radiation Management ◽

Atmospheric Conditions ◽

Concurrent Case ◽

Radiation Management

Abstract. Both explosive volcanic eruptions, which emit sulfur dioxide into the stratosphere, and stratospheric geoengineering via sulfur injections can potentially cool the climate by increasing the amount of scattering particles in the atmosphere. Here we employ a global aerosol-climate model and an earth system model to study the radiative and climate impacts of an erupting volcano during solar radiation management (SRM). According to our simulations, the radiative impacts of an eruption and SRM are not additive: in the simulated case of concurrent eruption and SRM, the peak increase in global forcing is about 40 % lower compared to a corresponding eruption into a clean background atmosphere. In addition, the recovery of the stratospheric sulfate burden and forcing was significantly faster in the concurrent case since the sulfate particles grew larger and thus sedimented faster from the stratosphere. In our simulation where we assumed that SRM would be stopped immediately after a volcano eruption, stopping SRM decreased the overall stratospheric aerosol load. For the same reasons, a volcanic eruption during SRM lead to only about 1/3 of the peak global ensemble-mean cooling compared to an eruption under unperturbed atmospheric conditions. Furthermore, the global cooling signal was seen only for 12 months after the eruption in the former scenario compared to over 40 months in the latter. In terms of the global precipitation rate, we obtain a 36 % smaller decrease in the first year after the eruption and again a clearly faster recovery in the concurrent eruption and SRM scenario. We also found that an explosive eruption could lead to significantly different regional climate responses depending on whether it takes place during geoengineering or into an unperturbed background atmosphere. Our results imply that observations from previous large eruptions, such as Mt Pinatubo in 1991, are not directly applicable when estimating the potential consequences of a volcanic eruption during stratospheric geoengineering.

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Impact of climate change on volcanic processes: current understanding and future challenges

10.31223/x58s5q ◽

2021 ◽

Author(s):

Thomas Aubry ◽

Jamie Farquharson ◽

Colin Rowell ◽

Sebastian Watt ◽

Virginie Pinel ◽

...

Keyword(s):

Climate Change ◽

Radiative Forcing ◽

Climate Changes ◽

Numerical Models ◽

Anthropogenic Activities ◽

Volcanic Eruptions ◽

Climate Impacts ◽

Volcanic Plume ◽

Atmospheric Conditions ◽

Climate Conditions

The impacts of volcanic eruptions on climate are increasingly well understood, but the mirror question of how climate changes affect volcanic systems and processes, which we term “climate-volcano impacts”, remains understudied. Accelerating research on this topic is critical in view of rapid climate change driven by anthropogenic activities. Over the last two decades, we have improved our understanding of how mass distribution on the Earth’s surface, in particular changes in ice and water distribution linked to glacial cycles, affects mantle melting, crustal magmatic processing and eruption rates. New hypotheses on the impacts of climate change on eruption processes have also emerged, including how eruption style and volcanic plume rise are affected by changing surface and atmospheric conditions, and how volcanic sulfate aerosol lifecycle, radiative forcing and climate impacts are modulated by background climate conditions. Future improvements in past climate reconstructions and current climate observations, volcanic eruption records and volcano monitoring, and numerical models will contribute to boost research on climate-volcano impacts. Important mechanisms remain to be explored, such as how changes in atmospheric circulation and precipitation will affect the volcanic ash lifecycle. Fostering a holistic and interdisciplinary approach to climate-volcano impacts is critical to gain a full picture of how ongoing climate changes may affect the environmental and societal impacts of volcanic activity.

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Substantial Climate Response outside the Target Area in an Idealized Experiment of Regional Radiation Management

Climate ◽

10.3390/cli9040066 ◽

2021 ◽

Vol 9 (4) ◽

pp. 66

Author(s):

Sudhakar Dipu ◽

Johannes Quaas ◽

Martin Quaas ◽

Wilfried Rickels ◽

Johannes Mülmenstädt ◽

...

Keyword(s):

Radiative Forcing ◽

Climate Model ◽

Heat Waves ◽

Climate Impacts ◽

The Arctic ◽

Solar Radiation Management ◽

Target Area ◽

Local Cooling ◽

Target Region ◽

Radiation Management

Radiation management (RM) has been proposed as a conceivable climate engineering (CE) intervention to mitigate global warming. In this study, we used a coupled climate model (MPI-ESM) with a very idealized setup to investigate the efficacy and risks of CE at a local scale in space and time (regional radiation management, RRM) assuming that cloud modification is technically possible. RM is implemented in the climate model by the brightening of low-level clouds (solar radiation management, SRM) and thinning of cirrus (terrestrial radiation management, TRM). The region chosen is North America, and we simulated a period of 30 years. The implemented sustained RM resulted in a net local radiative forcing of −9.8 Wm−2 and a local cooling of −0.8 K. Surface temperature (SAT) extremes (90th and 10th percentiles) show negative anomalies in the target region. However, substantial climate impacts were also simulated outside the target area, with warming in the Arctic and pronounced precipitation change in the eastern Pacific. As a variant of RRM, a targeted intervention to suppress heat waves (HW) was investigated in further simulations by implementing intermittent cloud modification locally, prior to the simulated HW situations. In most cases, the intermittent RRM results in a successful reduction of temperatures locally, with substantially smaller impacts outside the target area compared to the sustained RRM.

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ENSO sensitivity to radiative forcing

10.5194/egusphere-egu2020-11931 ◽

2020 ◽

Author(s):

Evgeniya Predybaylo ◽

Georgiy Stenchikov ◽

Andrew Wittenberg ◽

Sergey Osipov

Keyword(s):

Radiative Forcing ◽

Climate Model ◽

Southern Oscillation ◽

Volcanic Eruptions ◽

Boreal Winter ◽

Unified Framework ◽

Surface Cooling ◽

Radiative Forcings ◽

Global Mean ◽

Eruption Magnitude

To improve El Ni&#241;o / Southern Oscillation (ENSO) predictions and projections in a changing climate, it is essential to better understand ENSO&#8217;s sensitivities to external radiative forcings. Strong volcanic eruptions can help to clarify ENSO&#8217;s sensitivities, mechanisms, and feedbacks. Strong explosive volcanic eruptions inject millions of tons of sulfur dioxide into the stratosphere, where they are converted into sulfate aerosols. For equatorial volcanoes, these aerosols can spread globally, scattering and absorbing incoming sunlight, and inducing a global-mean surface cooling. Despite this global-mean cooling effect, paleo data confirm remarkable warming of the eastern equatorial Pacific in the two years after a tropical eruption, with a shift towards an El Ni&#241;o-like state. To illuminate this response and explain why it tends to occur during particular seasons and ENSO phases, we present a unified framework that includes the roles of the seasonal cycle, stochastic wind forcing, eruption magnitude, and various tropical Pacific climate feedbacks. Analyzing over 20,000 years of large-ensemble simulations from the GFDL-CM2.1 climate model forced by volcanic eruptions, we find that the ENSO response comprises both stochastic and deterministic components, which vary depending on the perturbation season and the ocean preconditioning. For boreal winter eruptions, stochastic dispersion largely obscures the deterministic response, being the largest for the strong El Ni&#241;o preconditioning. Deterministic El Ni&#241;o-like responses to summer eruptions are well seen on neutral ENSO and weak to moderate El Ni&#241;o preconditioning and grow with the eruption magnitude. The relative balance of these components determines the predictability and strength of the ENSO response. The results clarify why previous studies obtained seemingly conflicting results.

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Radiative Forcing of Climate: The Historical Evolution of the Radiative Forcing Concept, the Forcing Agents and their Quantification, and Applications

Meteorological Monographs ◽

10.1175/amsmonographs-d-19-0001.1 ◽

2019 ◽

Vol 59 ◽

pp. 14.1-14.101 ◽

Cited By ~ 9

Author(s):

V. Ramaswamy ◽

W. Collins ◽

J. Haywood ◽

J. Lean ◽

N. Mahowald ◽

...

Keyword(s):

Carbon Dioxide ◽

Surface Temperature ◽

Radiative Forcing ◽

Global Climate ◽

Volcanic Eruptions ◽

Climate Impacts ◽

Climate System ◽

Radiative Energy ◽

Forcing Mechanisms ◽

Global Mean

Abstract We describe the historical evolution of the conceptualization, formulation, quantification, application, and utilization of “radiative forcing” (RF) of Earth’s climate. Basic theories of shortwave and longwave radiation were developed through the nineteenth and twentieth centuries and established the analytical framework for defining and quantifying the perturbations to Earth’s radiative energy balance by natural and anthropogenic influences. The insight that Earth’s climate could be radiatively forced by changes in carbon dioxide, first introduced in the nineteenth century, gained empirical support with sustained observations of the atmospheric concentrations of the gas beginning in 1957. Advances in laboratory and field measurements, theory, instrumentation, computational technology, data, and analysis of well-mixed greenhouse gases and the global climate system through the twentieth century enabled the development and formalism of RF; this allowed RF to be related to changes in global-mean surface temperature with the aid of increasingly sophisticated models. This in turn led to RF becoming firmly established as a principal concept in climate science by 1990. The linkage with surface temperature has proven to be the most important application of the RF concept, enabling a simple metric to evaluate the relative climate impacts of different agents. The late 1970s and 1980s saw accelerated developments in quantification, including the first assessment of the effect of the forcing due to the doubling of carbon dioxide on climate (the “Charney” report). The concept was subsequently extended to a wide variety of agents beyond well-mixed greenhouse gases (WMGHGs; carbon dioxide, methane, nitrous oxide, and halocarbons) to short-lived species such as ozone. The WMO and IPCC international assessments began the important sequence of periodic evaluations and quantifications of the forcings by natural (solar irradiance changes and stratospheric aerosols resulting from volcanic eruptions) and a growing set of anthropogenic agents (WMGHGs, ozone, aerosols, land surface changes, contrails). From the 1990s to the present, knowledge and scientific confidence in the radiative agents acting on the climate system have proliferated. The conceptual basis of RF has also evolved as both our understanding of the way radiative forcing drives climate change and the diversity of the forcing mechanisms have grown. This has led to the current situation where “effective radiative forcing” (ERF) is regarded as the preferred practical definition of radiative forcing in order to better capture the link between forcing and global-mean surface temperature change. The use of ERF, however, comes with its own attendant issues, including challenges in its diagnosis from climate models, its applications to small forcings, and blurring of the distinction between rapid climate adjustments (fast responses) and climate feedbacks; this will necessitate further elaboration of its utility in the future. Global climate model simulations of radiative perturbations by various agents have established how the forcings affect other climate variables besides temperature (e.g., precipitation). The forcing–response linkage as simulated by models, including the diversity in the spatial distribution of forcings by the different agents, has provided a practical demonstration of the effectiveness of agents in perturbing the radiative energy balance and causing climate changes. The significant advances over the past half century have established, with very high confidence, that the global-mean ERF due to human activity since preindustrial times is positive (the 2013 IPCC assessment gives a best estimate of 2.3 W m−2, with a range from 1.1 to 3.3 W m−2; 90% confidence interval). Further, except in the immediate aftermath of climatically significant volcanic eruptions, the net anthropogenic forcing dominates over natural radiative forcing mechanisms. Nevertheless, the substantial remaining uncertainty in the net anthropogenic ERF leads to large uncertainties in estimates of climate sensitivity from observations and in predicting future climate impacts. The uncertainty in the ERF arises principally from the incorporation of the rapid climate adjustments in the formulation, the well-recognized difficulties in characterizing the preindustrial state of the atmosphere, and the incomplete knowledge of the interactions of aerosols with clouds. This uncertainty impairs the quantitative evaluation of climate adaptation and mitigation pathways in the future. A grand challenge in Earth system science lies in continuing to sustain the relatively simple essence of the radiative forcing concept in a form similar to that originally devised, and at the same time improving the quantification of the forcing. This, in turn, demands an accurate, yet increasingly complex and comprehensive, accounting of the relevant processes in the climate system.

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Large variations in volcanic aerosol forcing efficiency due to eruption source parameters and rapid adjustments

10.5194/egusphere-egu2020-5254 ◽

2020 ◽

Author(s):

Lauren Marshall ◽

Christopher Smith ◽

Piers Forster ◽

Thomas Aubry ◽

Anja Schmidt

Keyword(s):

Radiative Forcing ◽

Climate Model ◽

Source Parameters ◽

Volcanic Eruptions ◽

Stratospheric Aerosol ◽

Climate Impacts ◽

Intergovernmental Panel ◽

Aerosol Forcing ◽

Effective Radiative Forcing ◽

Climate Model Simulations

The relationship between volcanic stratospheric aerosol optical depth (SAOD) and volcanic forcing is key to quantify the climate impacts of volcanic eruptions. In their fifth assessment report, the Intergovernmental Panel on Climate Change uses a single scaling factor between volcanic SAOD and effective radiative forcing (ERF) based on climate model simulations of the 1991 Mt. Pinatubo eruption, which may not be appropriate for eruptions of different magnitudes. Using a large-ensemble of aerosol-chemistry-climate simulations of eruptions with different SO2 emissions, latitudes, emission altitudes and seasons, we find that the effective radiative forcing is on average 21% less than the instantaneous radiative forcing, predominantly due to a positive shortwave cloud adjustment. &#160;In our model, the volcanic SAOD to ERF relationship is non-unique and depends strongly on eruption latitude and season. We recommend a power law fit in the form of ERF = -15.1 &#215; SAOD0.88 to convert SAOD (in the range of 0.01-0.7) to ERF.

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The influence of global climate changes on Western Siberia climate in the first half of XXI century

Вычислительные технологии ◽

10.25743/ict.2018.23.16505 ◽

2018 ◽

Author(s):

А.А. Лагутин ◽

Н.В. Волков ◽

Е.Ю. Мордвин

Keyword(s):

Radiative Forcing ◽

Climate Changes ◽

Western Siberia ◽

Climate Model ◽

Global Climate ◽

Regional Climate ◽

First Century ◽

Global Climate Changes ◽

Rcp 8.5

Представлены результаты исследований влияния глобальных климатических изменений системы Земля на климат Западной Сибири. Для установления зон региона, в которых к середине XXI в. прогнозируются изменения, использовались модельные данные региональной климатической модели RegCM4 и принятые в этом классе задач стандартизованные евклидовы расстояния между характеристиками климата для двух состояний климатической системы — современного и будущего. Установлены зоны Западной Сибири, в которых в рамках сценариев RCP 4.5 и RCP 8.5 возможной эволюции глобальной системы к 2050 г. прогнозируются изменения климата. Purpose. An analysis of the influence of a global climate changes on the climate of Western Siberia, determination of zones of the region where changes are expected in the middle of the twenty-first century. Methodology. Results obtained using the model data of the regional climate model RegCM4 and the standardized Euclidean distances between climate characteristics. Findings, originality. Simulations of the climate characteristics for the two states of the climate system — contemporary and future — have been carried out. The zones of Western Siberia region, in which climate change is expected in the framework of RCP 4.5 and RCP 8.5 radiative forcing scenarios by the 2050, have been determined.

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Atmospheric circulation and hydroclimate impacts of alternative warming scenarios for the Eocene

Climate of the Past ◽

10.5194/cp-13-1037-2017 ◽

2017 ◽

Vol 13 (8) ◽

pp. 1037-1048 ◽

Cited By ~ 2

Author(s):

Henrik Carlson ◽

Rodrigo Caballero

Keyword(s):

Surface Temperature ◽

Radiative Forcing ◽

Climate Models ◽

Climate Model ◽

Regional Climate ◽

Warm Season ◽

Cloud Albedo ◽

Cloud Properties ◽

Atmospheric Co2 Concentrations ◽

Global Mean

Abstract. Recent work in modelling the warm climates of the early Eocene shows that it is possible to obtain a reasonable global match between model surface temperature and proxy reconstructions, but only by using extremely high atmospheric CO2 concentrations or more modest CO2 levels complemented by a reduction in global cloud albedo. Understanding the mix of radiative forcing that gave rise to Eocene warmth has important implications for constraining Earth's climate sensitivity, but progress in this direction is hampered by the lack of direct proxy constraints on cloud properties. Here, we explore the potential for distinguishing among different radiative forcing scenarios via their impact on regional climate changes. We do this by comparing climate model simulations of two end-member scenarios: one in which the climate is warmed entirely by CO2 (which we refer to as the greenhouse gas (GHG) scenario) and another in which it is warmed entirely by reduced cloud albedo (which we refer to as the low CO2–thin clouds or LCTC scenario) . The two simulations have an almost identical global-mean surface temperature and equator-to-pole temperature difference, but the LCTC scenario has ∼  11 % greater global-mean precipitation than the GHG scenario. The LCTC scenario also has cooler midlatitude continents and warmer oceans than the GHG scenario and a tropical climate which is significantly more El Niño-like. Extremely high warm-season temperatures in the subtropics are mitigated in the LCTC scenario, while cool-season temperatures are lower at all latitudes. These changes appear large enough to motivate further, more detailed study using other climate models and a more realistic set of modelling assumptions.

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Impact of biogenic hydrocarbons on tropospheric chemistry: results from a global chemistry-climate model

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-5-10517-2005 ◽

2005 ◽

Vol 5 (5) ◽

pp. 10517-10612 ◽

Cited By ~ 8

Author(s):

G. A. Folberth ◽

D. A. Hauglustaine ◽

J. Lathière ◽

F. Brocheton

Keyword(s):

Tropospheric Ozone ◽

Radiative Forcing ◽

Climate Model ◽

Primary Source ◽

Tropospheric Chemistry ◽

Secondary Source ◽

Peroxy Radicals ◽

Substantial Impact ◽

The Impact ◽

Global Mean

Abstract. We present a description and evaluation of LMDz-INCA, a global three-dimensional chemistry-climate model, pertaining to its recently developed NMHC version. In this substantially extended version of the model a comprehensive representation of the photochemistry of non-methane hydrocarbons (NMHC) and volatile organic compounds (VOC) from biogenic, anthropogenic, and biomass-burning sources has been included. The tropospheric annual mean methane (9.2 years) and methylchloroform (5.5 years) chemical lifetimes are well within the range of previous modelling studies and are in excellent agreement with estimates established by means of global observations. The model provides a reasonable simulation of the horizontal and vertical distribution and seasonal cycle of CO and key non-methane VOC, such as acetone, methanol, and formaldehyde as compared to observational data from several ground stations and aircraft campaigns. LMDz-INCA in the NMHC version reproduces tropospheric ozone concentrations fairly well throughout most of the troposphere. The model is applied in several sensitivity studies of the biosphere-atmosphere photochemical feedback. The impact of surface emissions of isoprene, acetone, and methanol is studied. These experiments show a substantial impact of isoprene on tropospheric ozone and carbon monoxide concentrations revealing an increase in surface O3 and CO levels of up to 30 ppbv and 60 ppbv, respectively. Isoprene also appears to significantly impact the global OH distribution resulting in a decrease of the global mean tropospheric OH concentration by approximately 0.9×105 molecules cm−3 or roughly 10% and an increase in the global mean tropospheric methane lifetime by approximately four months. A global mean ozone net radiative forcing due to the isoprene induced increase in the tropospheric ozone burden of 0.09W m−2 is found. The key role of isoprene photooxidation in the global tropospheric redistribution of NOx is demonstrated. LMDz-INCA calculates an increase of PAN surface mixing ratios ranging from 75 to 750 pptv and 10 to 250 pptv during northern hemispheric summer and winter, respectively. Acetone and methanol are found to play a significant role in the upper troposphere/lower stratosphere (UT/LS) budget of peroxy radicals. Calculations with LMDz-INCA show an increase in HOx concentrations region of 8 to 15% and 10 to 15% due to methanol and acetone biogenic surface emissions, respectively. The model has been used to estimate the global tropospheric CO budget. A global CO source of 3019 TgCO yr−1 is estimated. This source divides into a primary source of 1533 TgCO yr−1 and secondary source of 1489 TgCO yr−1 deriving from VOC photooxidation. Global VOC-to-CO conversion efficiencies of 90% for methane and between 20 and 45% for individual VOC are calculated by LMDz-INCA.

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Climate variability following large volcanic eruption: CMIP6 model investigation

10.5194/egusphere-egu21-3686 ◽

2021 ◽

Author(s):

Elizaveta Malinina ◽

Nathan Gillett

Keyword(s):

Climate Variability ◽

Volcanic Eruption ◽

Volcanic Eruptions ◽

Arctic Sea Ice ◽

Evaluation Tool ◽

Global Mean Temperature ◽

Arctic Sea ◽

Global Mean Surface Temperature ◽

Krakatoa Eruption ◽

Global Mean

Volcanic eruptions are an important driver of climate variability. Multiple literature sources have shown that after large explosive eruptions there is a decrease in global mean temperature, caused by an increased amount of stratospheric aerosols which influence the global radiative budget. In this study, we investigate the changes in several climate variables after a volcanic eruption. Using ESMValTool (Earth System Model Evaluation Tool) on an ensemble of historical simulations from CMIP6, such variables as global mean surface temperature (GMST), Arctic sea ice area and Nino 3.4 index were analyzed following the 1883 Krakatoa eruption. While there is a definite decrease in the multi-model mean GMST after the eruption, other indices do not show as prominent change. The reasons for this behavior are under investigation.&#160;

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