Articles | Volume 19, issue 9
https://doi.org/10.5194/gmd-19-3725-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/gmd-19-3725-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Stratospheric aerosol forcing for CMIP7 – Part 1: optical properties for pre-industrial, historical, and scenario simulations
Thomas J. Aubry
CORRESPONDING AUTHOR
Department of Earth and Environmental Sciences, University of Exeter, Penryn, UK
now at: Department of Earth Sciences, University of Oxford, Oxford, UK
Matthew Toohey
Institute of Space and Atmospheric Studies, University of Saskatchewan, Saskatoon, S7N 5A2, Canada
Sujan Khanal
Institute of Space and Atmospheric Studies, University of Saskatchewan, Saskatoon, S7N 5A2, Canada
Man Mei Chim
Department of Mathematics and Statistics, University of Exeter, Exeter, UK
Magali Verkerk
Department of Earth and Environmental Sciences, University of Exeter, Penryn, UK
now at: Department of Earth Sciences, University of Oxford, Oxford, UK
Ben Johnson
Met Office Hadley Centre, Exeter, UK
Anja Schmidt
Institute of Atmospheric Physics (IPA), German Aerospace Center (DLR), Oberpfaffenhofen, Germany
Meteorological Institute, Ludwig Maximilian University of Munich, Munich, Germany
Mahesh Kovilakam
NASA Langley Research Center, Hampton, Virginia, USA
ADNET Systems Inc, Bethesda, MD, USA
Michael Sigl
Institute of History & Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
now at: NOAA Geophysical Fluid Dynamics Laboratory, Princeton, NJ, USA
Zebedee Nicholls
Climate Resource, Berlin, Germany
Energy, Climate and Environment Program, International Institute for Applied Systems Analysis (IIASA), 2361 Laxenburg, Austria
School of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Melbourne, Victoria, Australia
Larry Thomason
NASA Langley Research Center, Hampton, Virginia, USA
retired
Vaishali Naik
NOAA Geophysical Fluid Dynamics Laboratory, Princeton, NJ, USA
Landon Rieger
Environment and Climate Change Canada, Victoria BC, CA
Dominik Stiller
Department of Atmospheric and Climate Science, University of Washington, Seattle, WA, USA
Elisa Ziegler
Department of Geosciences, University of Tübingen, Tübingen, Germany
Paul Durack
Program for Climate Model Diagnosis and Intercomparison (PCMDI), Lawrence Livermore National Laboratory, Livermore, CA, USA
Oceans Institute, University of Western Australia, 64 Fairway, Crawley, Perth, WA 6009, Australia
Department of Water and Environmental Regulation, Prime House, 8 Davidson Terrace, Joondalup, WA 6919, Australia
Isabel H. Smith
Department of Earth and Environmental Sciences, University of Exeter, Penryn, UK
now at: Department of Earth Sciences, University of Oxford, Oxford, UK
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Rachel C. W. Whitty, Evgenia Ilyinskaya, Melissa A. Pfeffer, Ragnar H. Thrastarson, Þorsteinn Johannsson, Sara Barsotti, Tjarda J. Roberts, Guðni M. Gilbert, Tryggvi Hjörvar, Anja Schmidt, Daniela Fecht, and Grétar G. Sæmundsson
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Sujan Khanal, Matthew Toohey, Adam Bourassa, C. Thomas McElroy, Christopher Sioris, and Kaley A. Walker
Atmos. Meas. Tech., 18, 6835–6852, https://doi.org/10.5194/amt-18-6835-2025, https://doi.org/10.5194/amt-18-6835-2025, 2025
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Measurements of stratospheric aerosol from the Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation (MAESTRO) instrument are compared to other measurements to assess their scientific value. We find that medians of MAESTRO measurements binned by month and latitude show reasonable correlation with other data sets, with notable increases after volcanic eruptions, and that biases in the data can be alleviated through a simple correction technique. Used with care, MAESTRO aerosol measurements provide information that can complement other data sets.
Alkiviadis Kalisoras, Prodromos Zanis, Aristeidis K. Georgoulias, Dimitris Akritidis, Robert J. Allen, and Vaishali Naik
EGUsphere, https://doi.org/10.5194/egusphere-2025-4961, https://doi.org/10.5194/egusphere-2025-4961, 2025
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Monica Sharma, Mattia Righi, Johannes Hendricks, Anja Schmidt, Daniel Sauer, and Volker Grewe
Geosci. Model Dev., 18, 8485–8510, https://doi.org/10.5194/gmd-18-8485-2025, https://doi.org/10.5194/gmd-18-8485-2025, 2025
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Eric J. Mei, Gregory J. Hakim, Max Taniguchi-King, Dominik Stiller, and Alexander J. Turner
Atmos. Chem. Phys., 25, 15033–15045, https://doi.org/10.5194/acp-25-15033-2025, https://doi.org/10.5194/acp-25-15033-2025, 2025
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Natalie G. Ratcliffe, Claire L. Ryder, Nicolas Bellouin, Anthony Jones, Ben Johnson, Stephanie Woodward, Lisa-Maria Wieland, Josef Gasteiger, and Bernadett Weinzierl
EGUsphere, https://doi.org/10.5194/egusphere-2025-5143, https://doi.org/10.5194/egusphere-2025-5143, 2025
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Observations show large dust particles travel much further than expected, which is not replicated in weather and climate models. We use a climate model to understand which processes dominantly impact large particle transport, and find that modelled large particle transport agrees with observations best after reducing the particle gravitational settling by ~ 80 %. We prove the presence of processes not represented accurately or at all in the model which act on large particles in the real-world.
Daniel Letros, Liam Graham, Adam Bourassa, Doug Degenstein, Paul Loewen, Landon Rieger, and Nick Lloyd
Atmos. Meas. Tech., 18, 6185–6210, https://doi.org/10.5194/amt-18-6185-2025, https://doi.org/10.5194/amt-18-6185-2025, 2025
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The Aerosol Limb Imager (ALI) is an optical instrument which measures stratospheric aerosols. These aerosols are of interest to atmospheric science as they have a significant impact on the Earth's climate. ALI has the ability to measure the polarization of atmospheric light over a wide spectral range, which is a novel ability for the measurement ALI uses. We demonstrate and discuss ALI capability and how the polarized information may improve aerosol information for this type of measurement.
George Jordan, Florent Malavelle, Jim Haywood, Ying Chen, Ben Johnson, Daniel Partridge, Amy Peace, Eliza Duncan, Duncan Watson-Parris, David Neubauer, Anton Laakso, Martine Michou, and Pierre Nabat
Atmos. Chem. Phys., 25, 13393–13428, https://doi.org/10.5194/acp-25-13393-2025, https://doi.org/10.5194/acp-25-13393-2025, 2025
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The 2014–15 Holuhraun eruption created a vast aerosol plume that acted as a natural experiment to assess how well climate models capture changes in cloud properties due to increased aerosol. We find that climate models represent the observed shift to smaller, more numerous cloud droplets well. However, climate models diverge in their aerosol-induced changes to large-scale cloud properties, particularly cloud liquid water content. Our study shows that Holuhraun had a cooling effect on the Earth.
Magali Verkerk, Thomas J. Aubry, Chris Smith, Peter O. Hopcroft, Michael Sigl, Jessica E. Tierney, Kevin Anchukaitis, Matthew Osman, Anja Schmidt, and Matthew Toohey
Clim. Past, 21, 1755–1778, https://doi.org/10.5194/cp-21-1755-2025, https://doi.org/10.5194/cp-21-1755-2025, 2025
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Large volcanic eruptions can trigger global cooling, affecting human societies. Using ice-core records and simple climate model to simulate volcanic effect over the last 8500 years, we show that volcanic eruptions cool the climate by 0.12 °C on average. By comparing model results with temperature recorded by tree rings over the last 1000 years, we demonstrate that our models can predict the large-scale cooling caused by volcanic eruptions and can be used in cases of large eruptions in the future.
John P. Dunne, Helene T. Hewitt, Julie M. Arblaster, Frédéric Bonou, Olivier Boucher, Tereza Cavazos, Beth Dingley, Paul J. Durack, Birgit Hassler, Martin Juckes, Tomoki Miyakawa, Matt Mizielinski, Vaishali Naik, Zebedee Nicholls, Eleanor O'Rourke, Robert Pincus, Benjamin M. Sanderson, Isla R. Simpson, and Karl E. Taylor
Geosci. Model Dev., 18, 6671–6700, https://doi.org/10.5194/gmd-18-6671-2025, https://doi.org/10.5194/gmd-18-6671-2025, 2025
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The seventh phase of the Coupled Model Intercomparison Project (CMIP7) coordinates efforts to answer key and timely climate science questions and facilitate delivery of relevant multi-model simulations for prediction and projection; characterization, attribution, and process understanding; and vulnerability, impact, and adaptation analysis. Key to the CMIP7 design are the mandatory Diagnostic, Evaluation and Characterization of Klima and optional Assessment Fast Track experiments.
Roberto Bilbao, Thomas J. Aubry, Matthew Toohey, Pablo Ortega, Vladimir Lapin, and Etienne Tourigny
Geosci. Model Dev., 18, 6239–6254, https://doi.org/10.5194/gmd-18-6239-2025, https://doi.org/10.5194/gmd-18-6239-2025, 2025
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Large volcanic eruptions are unpredictable and can have significant climatic impacts. If one occurs, operational decadal forecasts will become invalid and must be rerun including the volcanic forcing. By analyzing the climate response in EC-Earth3 retrospective predictions, we show that idealised forcings produced with two simple models could be used in operational decadal forecasts to account for the radiative impacts of the next major volcanic eruption.
Benjamin M. Sanderson, Victor Brovkin, Rosie A. Fisher, David Hohn, Tatiana Ilyina, Chris D. Jones, Torben Koenigk, Charles Koven, Hongmei Li, David M. Lawrence, Peter Lawrence, Spencer Liddicoat, Andrew H. MacDougall, Nadine Mengis, Zebedee Nicholls, Eleanor O'Rourke, Anastasia Romanou, Marit Sandstad, Jörg Schwinger, Roland Séférian, Lori T. Sentman, Isla R. Simpson, Chris Smith, Norman J. Steinert, Abigail L. S. Swann, Jerry Tjiputra, and Tilo Ziehn
Geosci. Model Dev., 18, 5699–5724, https://doi.org/10.5194/gmd-18-5699-2025, https://doi.org/10.5194/gmd-18-5699-2025, 2025
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This study investigates how climate models warm in response to simplified carbon emissions trajectories, refining the understanding of climate reversibility and commitment. Metrics are defined for warming response to cumulative emissions and for the cessation of emissions or ramp-down to net-zero and net-negative levels. Results indicate that previous concentration-driven experiments may have overstated the Zero Emissions Commitment due to emissions rates exceeding historical levels.
Trevor Martin Sloughter, Zebedee Nicholls, Gang Tang, Thomas Kleinen, Zhen Zhang, and Joeri Rogelj
EGUsphere, https://doi.org/10.5194/egusphere-2025-3873, https://doi.org/10.5194/egusphere-2025-3873, 2025
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High resolution models of the earth system exhibit some disagreement and uncertainty on future methane emissions from natural sources, in particular wetlands, with some studies predicting wetlands alone could be very significant sources over the 21st century. Modelling these emissions as a response to global temperature is one option for simple models to approximate the climate impact of wetlands. The effect is a small increase in overall temperatures and a widening of the uncertainty range.
Yunqian Zhu, Hideharu Akiyoshi, Valentina Aquila, Elizabeth Asher, Ewa M. Bednarz, Slimane Bekki, Christoph Brühl, Amy H. Butler, Parker Case, Simon Chabrillat, Gabriel Chiodo, Margot Clyne, Peter R. Colarco, Sandip Dhomse, Lola Falletti, Eric Fleming, Ben Johnson, Andrin Jörimann, Mahesh Kovilakam, Gerbrand Koren, Ales Kuchar, Nicolas Lebas, Qing Liang, Cheng-Cheng Liu, Graham Mann, Michael Manyin, Marion Marchand, Olaf Morgenstern, Paul Newman, Luke D. Oman, Freja F. Østerstrøm, Yifeng Peng, David Plummer, Ilaria Quaglia, William Randel, Samuel Rémy, Takashi Sekiya, Stephen Steenrod, Timofei Sukhodolov, Simone Tilmes, Kostas Tsigaridis, Rei Ueyama, Daniele Visioni, Xinyue Wang, Shingo Watanabe, Yousuke Yamashita, Pengfei Yu, Wandi Yu, Jun Zhang, and Zhihong Zhuo
Geosci. Model Dev., 18, 5487–5512, https://doi.org/10.5194/gmd-18-5487-2025, https://doi.org/10.5194/gmd-18-5487-2025, 2025
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To understand the climate impact of the 2022 Hunga volcanic eruption, we developed a climate model–observation comparison project. The paper describes the protocols and models that participate in the experiments. We designed several experiments to achieve our goals of this activity: (1) to evaluate the climate model performance and (2) to understand the Earth system responses to this eruption.
William J. Collins, Fiona M. O'Connor, Rachael E. Byrom, Øivind Hodnebrog, Patrick Jöckel, Mariano Mertens, Gunnar Myhre, Matthias Nützel, Dirk Olivié, Ragnhild Bieltvedt Skeie, Laura Stecher, Larry W. Horowitz, Vaishali Naik, Gregory Faluvegi, Ulas Im, Lee T. Murray, Drew Shindell, Kostas Tsigaridis, Nathan Luke Abraham, and James Keeble
Atmos. Chem. Phys., 25, 9031–9060, https://doi.org/10.5194/acp-25-9031-2025, https://doi.org/10.5194/acp-25-9031-2025, 2025
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We used 7 climate models that include atmospheric chemistry and find that in a scenario with weak controls on air quality, the warming effects (over 2015 to 2050) of decreases in ozone-depleting substances and increases in air quality pollutants are approximately equal and would make ozone the second highest contributor to warming over this period. We find that for stratospheric ozone recovery, the standard measure of climate effects underestimates a more comprehensive measure.
Paul T. Griffiths, Laura J. Wilcox, Robert J. Allen, Vaishali Naik, Fiona M. O'Connor, Michael Prather, Alex Archibald, Florence Brown, Makoto Deushi, William Collins, Stephanie Fiedler, Naga Oshima, Lee T. Murray, Bjørn H. Samset, Chris Smith, Steven Turnock, Duncan Watson-Parris, and Paul J. Young
Atmos. Chem. Phys., 25, 8289–8328, https://doi.org/10.5194/acp-25-8289-2025, https://doi.org/10.5194/acp-25-8289-2025, 2025
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The Aerosol Chemistry Model Intercomparison Project (AerChemMIP) aimed to quantify the climate and air quality impacts of aerosols and chemically reactive gases. We review its contribution to AR6 (Sixth Assessment Report of the Intergovernmental Panel on Climate Change) and the wider understanding of the role of these species in climate and climate change. We identify challenges and provide recommendations to improve the utility and uptake of climate model data, detailed summary tables of CMIP6 models, experiments, and emergent diagnostics.
Nicholas Ernest, Larry W. Thomason, and Terry Deshler
Atmos. Meas. Tech., 18, 2957–2968, https://doi.org/10.5194/amt-18-2957-2025, https://doi.org/10.5194/amt-18-2957-2025, 2025
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We use balloon-borne measurements of aerosol size distribution (ASD) made by the University of Wyoming (UW) to derive distributions which are representative of the ASDs that underlie measurements made by the Stratospheric Aerosol and Gas Experiment II (SAGE II). A simple single-mode log-normal distribution has in the past been used to derive ASD from SAGE II data; here we derive bimodal log-normal distributions, reproducing median aerosol properties measured by UW.
Baylor Fox-Kemper, Patricia DeRepentigny, Anne Marie Treguier, Christian Stepanek, Eleanor O’Rourke, Chloe Mackallah, Alberto Meucci, Yevgeny Aksenov, Paul J. Durack, Nicole Feldl, Vanessa Hernaman, Céline Heuzé, Doroteaciro Iovino, Gaurav Madan, André L. Marquez, François Massonnet, Jenny Mecking, Dhrubajyoti Samanta, Patrick C. Taylor, Wan-Ling Tseng, and Martin Vancoppenolle
EGUsphere, https://doi.org/10.5194/egusphere-2025-3083, https://doi.org/10.5194/egusphere-2025-3083, 2025
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The earth system model variables needed for studies of the ocean and sea ice are prioritized and requested.
Piers M. Forster, Chris Smith, Tristram Walsh, William F. Lamb, Robin Lamboll, Christophe Cassou, Mathias Hauser, Zeke Hausfather, June-Yi Lee, Matthew D. Palmer, Karina von Schuckmann, Aimée B. A. Slangen, Sophie Szopa, Blair Trewin, Jeongeun Yun, Nathan P. Gillett, Stuart Jenkins, H. Damon Matthews, Krishnan Raghavan, Aurélien Ribes, Joeri Rogelj, Debbie Rosen, Xuebin Zhang, Myles Allen, Lara Aleluia Reis, Robbie M. Andrew, Richard A. Betts, Alex Borger, Jiddu A. Broersma, Samantha N. Burgess, Lijing Cheng, Pierre Friedlingstein, Catia M. Domingues, Marco Gambarini, Thomas Gasser, Johannes Gütschow, Masayoshi Ishii, Christopher Kadow, John Kennedy, Rachel E. Killick, Paul B. Krummel, Aurélien Liné, Didier P. Monselesan, Colin Morice, Jens Mühle, Vaishali Naik, Glen P. Peters, Anna Pirani, Julia Pongratz, Jan C. Minx, Matthew Rigby, Robert Rohde, Abhishek Savita, Sonia I. Seneviratne, Peter Thorne, Christopher Wells, Luke M. Western, Guido R. van der Werf, Susan E. Wijffels, Valérie Masson-Delmotte, and Panmao Zhai
Earth Syst. Sci. Data, 17, 2641–2680, https://doi.org/10.5194/essd-17-2641-2025, https://doi.org/10.5194/essd-17-2641-2025, 2025
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In a rapidly changing climate, evidence-based decision-making benefits from up-to-date and timely information. Here we compile monitoring datasets to track real-world changes over time. To make our work relevant to policymakers, we follow methods from the Intergovernmental Panel on Climate Change (IPCC). Human activities are increasing the Earth's energy imbalance and driving faster sea-level rise compared to the IPCC assessment.
Martin Juckes, Karl E. Taylor, Fabrizio Antonio, David Brayshaw, Carlo Buontempo, Jian Cao, Paul J. Durack, Michio Kawamiya, Hyungjun Kim, Tomas Lovato, Chloe Mackallah, Matthew Mizielinski, Alessandra Nuzzo, Martina Stockhause, Daniele Visioni, Jeremy Walton, Briony Turner, Eleanor O'Rourke, and Beth Dingley
Geosci. Model Dev., 18, 2639–2663, https://doi.org/10.5194/gmd-18-2639-2025, https://doi.org/10.5194/gmd-18-2639-2025, 2025
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The Baseline Climate Variables for Earth System Modelling (ESM-BCVs) are defined as a list of 135 variables which have high utility for the evaluation and exploitation of climate simulations. The list reflects the most frequently used variables from Earth system models based on an assessment of data publication and download records from the largest archive of global climate projects.
Gang Tang, Zebedee Nicholls, Alexander Norton, Sönke Zaehle, and Malte Meinshausen
Geosci. Model Dev., 18, 2193–2230, https://doi.org/10.5194/gmd-18-2193-2025, https://doi.org/10.5194/gmd-18-2193-2025, 2025
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We studied carbon–nitrogen coupling in Earth system models by developing a global carbon–nitrogen cycle model (CNit v1.0) within the widely used emulator MAGICC. CNit effectively reproduced the global carbon–nitrogen cycle dynamics observed in complex models. Our results show persistent nitrogen limitations on plant growth (net primary production) from 1850 to 2100, suggesting that nitrogen deficiency may constrain future land carbon sequestration.
Ngoc Thi Nhu Do, Kengo Sudo, Akihiko Ito, Louisa K. Emmons, Vaishali Naik, Kostas Tsigaridis, Øyvind Seland, Gerd A. Folberth, and Douglas I. Kelley
Geosci. Model Dev., 18, 2079–2109, https://doi.org/10.5194/gmd-18-2079-2025, https://doi.org/10.5194/gmd-18-2079-2025, 2025
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Understanding historical isoprene emission changes is important for predicting future climate, but trends and their controlling factors remain uncertain. This study shows that long-term isoprene trends vary among Earth system models mainly due to partially incorporating CO2 effects and land cover changes rather than to climate. Future models that refine these factors’ effects on isoprene emissions, along with long-term observations, are essential for better understanding plant–climate interactions.
Gang Tang, Zebedee Nicholls, Chris Jones, Thomas Gasser, Alexander Norton, Tilo Ziehn, Alejandro Romero-Prieto, and Malte Meinshausen
Geosci. Model Dev., 18, 2111–2136, https://doi.org/10.5194/gmd-18-2111-2025, https://doi.org/10.5194/gmd-18-2111-2025, 2025
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We analyzed carbon and nitrogen mass conservation in data from various Earth system models. Our findings reveal significant discrepancies between flux and pool size data, where cumulative imbalances can reach hundreds of gigatons of carbon or nitrogen. These imbalances appear primarily due to missing or inconsistently reported fluxes – especially for land-use and fire emissions. To enhance data quality, we recommend that future climate data protocols address this issue at the reporting stage.
Matthew Toohey, Yue Jia, Sujan Khanal, and Susann Tegtmeier
Atmos. Chem. Phys., 25, 3821–3839, https://doi.org/10.5194/acp-25-3821-2025, https://doi.org/10.5194/acp-25-3821-2025, 2025
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The climate impact of volcanic eruptions depends in part on how long aerosols spend in the stratosphere. We develop a conceptual model for stratospheric aerosol lifetime in terms of production and decay timescales, as well as a lag between injection and decay. We find residence time depends strongly on injection height in the lower stratosphere. We show that the lifetime of stratospheric aerosol from the 1991 Pinatubo eruption is around 22 months, significantly longer than is commonly reported.
Hazel Vernier, Demilson Quintão, Bruno Biazon, Eduardo Landulfo, Giovanni Souza, V. Amanda Santos, J. S. Fabio Lopes, C. P. Alex Mendes, A. S. José da Matta, K. Pinheiro Damaris, Benoit Grosslin, P. M. P. Maria Jorge, Maria de Fátima Andrade, Neeraj Rastogi, Akhil Raj, Hongyu Liu, Mahesh Kovilakam, Suvarna Fadnavis, Frank G. Wienhold, Mathieu Colombier, D. Chris Boone, Gwenael Berthet, Nicolas Dumelie, Lilian Joly, and Jean-Paul Vernier
EGUsphere, https://doi.org/10.5194/egusphere-2025-924, https://doi.org/10.5194/egusphere-2025-924, 2025
Preprint withdrawn
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The eruption of Hunga Tonga-Hunga Ha'apai injected large amounts of water vapor and sea salt into the stratosphere, altering traditional views of volcanic aerosols. Using balloon-borne samplers, we collected aerosol samples and found high levels of sea salt and calcium, suggesting sulfate depletion due to gypsum formation. These findings highlight the need to consider sea salt in climate models to better predict volcanic impacts on the atmosphere and climate.
Felix Wrana, Terry Deshler, Christian Löns, Larry W. Thomason, and Christian von Savigny
Atmos. Chem. Phys., 25, 3717–3736, https://doi.org/10.5194/acp-25-3717-2025, https://doi.org/10.5194/acp-25-3717-2025, 2025
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There is a natural and globally occurring layer of small droplets (aerosols) at roughly 20 km altitude in the atmosphere. In this work, the size of these droplets is calculated from satellite measurements for the years 2002 to 2005, which is important for the aerosol cooling effect on Earth's climate. These years are interesting because there were no large volcanic eruptions that would change the background state of the aerosols. The results are compared to reliable balloon-borne measurements.
Elisa Ziegler, Nils Weitzel, Jean-Philippe Baudouin, Marie-Luise Kapsch, Uwe Mikolajewicz, Lauren Gregoire, Ruza Ivanovic, Paul J. Valdes, Christian Wirths, and Kira Rehfeld
Clim. Past, 21, 627–659, https://doi.org/10.5194/cp-21-627-2025, https://doi.org/10.5194/cp-21-627-2025, 2025
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During the Last Deglaciation, global surface temperature rose by about 4–7 °C over several millennia. We show that changes in year-to-year up to century-to-century fluctuations of temperature and precipitation during the Deglaciation were mostly larger than during either the preceding or succeeding more stable periods in 15 climate model simulations. The analysis demonstrates how ice sheets, meltwater, and volcanism influence simulated variability to inform future simulation protocols.
Mariya Petrenko, Ralph Kahn, Mian Chin, Susanne E. Bauer, Tommi Bergman, Huisheng Bian, Gabriele Curci, Ben Johnson, Johannes W. Kaiser, Zak Kipling, Harri Kokkola, Xiaohong Liu, Keren Mezuman, Tero Mielonen, Gunnar Myhre, Xiaohua Pan, Anna Protonotariou, Samuel Remy, Ragnhild Bieltvedt Skeie, Philip Stier, Toshihiko Takemura, Kostas Tsigaridis, Hailong Wang, Duncan Watson-Parris, and Kai Zhang
Atmos. Chem. Phys., 25, 1545–1567, https://doi.org/10.5194/acp-25-1545-2025, https://doi.org/10.5194/acp-25-1545-2025, 2025
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We compared smoke plume simulations from 11 global models to each other and to satellite smoke amount observations aimed at constraining smoke source strength. In regions where plumes are thick and background aerosol is low, models and satellites compare well. However, the input emission inventory tends to underestimate in many places, and particle property and loss rate assumptions vary enormously among models, causing uncertainties that require systematic in situ measurements to resolve.
Xavier Faïn, Sophie Szopa, Vaishali Naïk, Patricia Martinerie, David M. Etheridge, Rachael H. Rhodes, Cathy M. Trudinger, Vasilii V. Petrenko, Kévin Fourteau, and Philip Place
Atmos. Chem. Phys., 25, 1105–1119, https://doi.org/10.5194/acp-25-1105-2025, https://doi.org/10.5194/acp-25-1105-2025, 2025
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Carbon monoxide (CO) plays a crucial role in the atmosphere's oxidizing capacity. In this study, we analyse how historical (1850–2014) [CO] outputs from state-of-the-art global chemistry–climate models over Greenland and Antarctica are able to capture both absolute values and trends recorded in multi-site ice archives. A disparity in [CO] growth rates emerges in the Northern Hemisphere between models and observations from 1920–1975 CE, possibly linked to uncertainties in CO emission factors.
Lauren R. Marshall, Anja Schmidt, Andrew P. Schurer, Nathan Luke Abraham, Lucie J. Lücke, Rob Wilson, Kevin J. Anchukaitis, Gabriele C. Hegerl, Ben Johnson, Bette L. Otto-Bliesner, Esther C. Brady, Myriam Khodri, and Kohei Yoshida
Clim. Past, 21, 161–184, https://doi.org/10.5194/cp-21-161-2025, https://doi.org/10.5194/cp-21-161-2025, 2025
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Large volcanic eruptions have caused temperature deviations over the past 1000 years; however, climate model results and reconstructions of surface cooling using tree rings do not match. We explore this mismatch using the latest models and find a better match to tree-ring reconstructions for some eruptions. Our results show that the way in which eruptions are simulated in models matters for the comparison to tree-rings, particularly regarding the spatial spread of volcanic aerosol.
Mahesh Kovilakam, Larry W. Thomason, Magali Verkerk, Thomas Aubry, and Travis N. Knepp
Atmos. Chem. Phys., 25, 535–553, https://doi.org/10.5194/acp-25-535-2025, https://doi.org/10.5194/acp-25-535-2025, 2025
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The Global Space-based Stratospheric Aerosol Climatology (GloSSAC) is essential for understanding and modeling the climatic impacts of stratospheric aerosols, comprising data from various space-based measurements. Here, we examine the Ozone Mapping and Profiler Suite Limb Profiler (OMPS-LP) against other data sets, particularly the Stratospheric Aerosol and Gas Experiment (SAGE) III/ISS, to discern differences and explore the applicability of OMPS data within the GloSSAC framework.
Paul J. Durack, Karl E. Taylor, Peter J. Gleckler, Gerald A. Meehl, Bryan N. Lawrence, Curt Covey, Ronald J. Stouffer, Guillaume Levavasseur, Atef Ben-Nasser, Sebastien Denvil, Martina Stockhause, Jonathan M. Gregory, Martin Juckes, Sasha K. Ames, Fabrizio Antonio, David C. Bader, John P. Dunne, Daniel Ellis, Veronika Eyring, Sandro L. Fiore, Sylvie Joussaume, Philip Kershaw, Jean-Francois Lamarque, Michael Lautenschlager, Jiwoo Lee, Chris F. Mauzey, Matthew Mizielinski, Paola Nassisi, Alessandra Nuzzo, Eleanor O’Rourke, Jeffrey Painter, Gerald L. Potter, Sven Rodriguez, and Dean N. Williams
EGUsphere, https://doi.org/10.5194/egusphere-2024-3729, https://doi.org/10.5194/egusphere-2024-3729, 2025
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CMIP6 was the most expansive and ambitious Model Intercomparison Project (MIP), the latest in a history, extending four decades. CMIP engaged a growing community focused on improving climate understanding, and quantifying and attributing observed climate change being experienced today. The project's profound impact is due to the combining the latest climate science and technology, enabling the latest-generation climate simulations and increasing community attention in every successive phase.
Evelien J. C. van Dijk, Christoph C. Raible, Michael Sigl, Johann Jungclaus, and Heinz Wanner
Clim. Past Discuss., https://doi.org/10.5194/cp-2024-79, https://doi.org/10.5194/cp-2024-79, 2024
Manuscript not accepted for further review
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The temperature in the past 4000 years consisted of warm and cold periods, initiated by external forcing. But, these periods are not consistent through time and space. We use climate models and reconstructions to study to which extent the periods are reflected in the European climate. We find that on local scales, the chaotic nature of the climate system is larger than the external forcing. This study shows that these periods have to be used very carefully when studying a local site.
Chris Smith, Donald P. Cummins, Hege-Beate Fredriksen, Zebedee Nicholls, Malte Meinshausen, Myles Allen, Stuart Jenkins, Nicholas Leach, Camilla Mathison, and Antti-Ilari Partanen
Geosci. Model Dev., 17, 8569–8592, https://doi.org/10.5194/gmd-17-8569-2024, https://doi.org/10.5194/gmd-17-8569-2024, 2024
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Climate projections are only useful if the underlying models that produce them are well calibrated and can reproduce observed climate change. We formalise a software package that calibrates the open-source FaIR simple climate model to full-complexity Earth system models. Observations, including historical warming, and assessments of key climate variables such as that of climate sensitivity are used to constrain the model output.
Alexei Rozanov, Christine Pohl, Carlo Arosio, Adam Bourassa, Klaus Bramstedt, Elizaveta Malinina, Landon Rieger, and John P. Burrows
Atmos. Meas. Tech., 17, 6677–6695, https://doi.org/10.5194/amt-17-6677-2024, https://doi.org/10.5194/amt-17-6677-2024, 2024
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We developed a new algorithm to retrieve vertical distributions of aerosol extinction coefficients in the stratosphere. The algorithm is applied to measurements of scattered solar light from the spaceborne OMPS-LP (Ozone Mapper and Profiler Suite Limb Profiler) instrument. The retrieval results are compared to data from other spaceborne instruments and used to investigate the evolution of the aerosol plume following the eruption of the Hunga Tonga–Hunga Ha'apai volcano in January 2022.
Jingmin Li, Mattia Righi, Johannes Hendricks, Christof G. Beer, Ulrike Burkhardt, and Anja Schmidt
Atmos. Chem. Phys., 24, 12727–12747, https://doi.org/10.5194/acp-24-12727-2024, https://doi.org/10.5194/acp-24-12727-2024, 2024
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Aiming to understand underlying patterns and trends in aerosols, we characterize the spatial patterns and long-term evolution of lower tropospheric aerosols by clustering multiple aerosol properties from preindustrial times to the year 2050 under three Shared
Socioeconomic Pathway scenarios. The results provide a clear and condensed picture of the spatial extent and distribution of aerosols for different time periods and emission scenarios.
Socioeconomic Pathway scenarios. The results provide a clear and condensed picture of the spatial extent and distribution of aerosols for different time periods and emission scenarios.
Viktoria F. Sofieva, Alexei Rozanov, Monika Szelag, John P. Burrows, Christian Retscher, Robert Damadeo, Doug Degenstein, Landon A. Rieger, and Adam Bourassa
Earth Syst. Sci. Data, 16, 5227–5241, https://doi.org/10.5194/essd-16-5227-2024, https://doi.org/10.5194/essd-16-5227-2024, 2024
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Climate-related studies need information about the distribution of stratospheric aerosols, which influence the energy balance of the Earth’s atmosphere. In this work, we present a merged dataset of vertically resolved stratospheric aerosol extinction coefficients, which is derived from data of six limb and occultation satellite instruments. The created aerosol climate record covers the period from October 1984 to December 2023. It can be used in various climate-related studies.
Natalie G. Ratcliffe, Claire L. Ryder, Nicolas Bellouin, Stephanie Woodward, Anthony Jones, Ben Johnson, Lisa-Maria Wieland, Maximilian Dollner, Josef Gasteiger, and Bernadett Weinzierl
Atmos. Chem. Phys., 24, 12161–12181, https://doi.org/10.5194/acp-24-12161-2024, https://doi.org/10.5194/acp-24-12161-2024, 2024
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Large mineral dust particles are more abundant in the atmosphere than expected and have different impacts on the environment than small particles, which are better represented in climate models. We use aircraft measurements to assess a climate model representation of large-dust transport. We find that the model underestimates the amount of large dust at all stages of transport and that fast removal of the large particles increases this underestimation with distance from the Sahara.
Christine Pohl, Felix Wrana, Alexei Rozanov, Terry Deshler, Elizaveta Malinina, Christian von Savigny, Landon A. Rieger, Adam E. Bourassa, and John P. Burrows
Atmos. Meas. Tech., 17, 4153–4181, https://doi.org/10.5194/amt-17-4153-2024, https://doi.org/10.5194/amt-17-4153-2024, 2024
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Knowledge of stratospheric aerosol characteristics is important for understanding chemical and climate aerosol feedbacks. Two particle size distribution parameters, the aerosol extinction coefficient and the effective radius, are obtained from SCIAMACHY limb observations. The aerosol characteristics show good agreement with independent data sets from balloon-borne and satellite observations. This data set expands the limited knowledge of stratospheric aerosol characteristics.
Alkiviadis Kalisoras, Aristeidis K. Georgoulias, Dimitris Akritidis, Robert J. Allen, Vaishali Naik, Chaincy Kuo, Sophie Szopa, Pierre Nabat, Dirk Olivié, Twan van Noije, Philippe Le Sager, David Neubauer, Naga Oshima, Jane Mulcahy, Larry W. Horowitz, and Prodromos Zanis
Atmos. Chem. Phys., 24, 7837–7872, https://doi.org/10.5194/acp-24-7837-2024, https://doi.org/10.5194/acp-24-7837-2024, 2024
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Effective radiative forcing (ERF) is a metric for estimating how human activities and natural agents change the energy flow into and out of the Earth’s climate system. We investigate the anthropogenic aerosol ERF, and we estimate the contribution of individual processes to the total ERF using simulations from Earth system models within the Coupled Model Intercomparison Project Phase 6 (CMIP6). Our findings highlight that aerosol–cloud interactions drive ERF variability during the last 150 years.
Moritz Günther, Hauke Schmidt, Claudia Timmreck, and Matthew Toohey
Atmos. Chem. Phys., 24, 7203–7225, https://doi.org/10.5194/acp-24-7203-2024, https://doi.org/10.5194/acp-24-7203-2024, 2024
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Stratospheric aerosol has been shown to cause pronounced cooling in the tropical Indian and western Pacific oceans. Using a climate model, we show that this arises from enhanced meridional energy export via the stratosphere. The aerosol causes stratospheric heating and thus an acceleration of the Brewer–Dobson circulation that accomplishes this transport. Our findings highlight the importance of circulation adjustments and surface perspectives on forcing for understanding temperature responses.
Robert P. Damadeo, Viktoria F. Sofieva, Alexei Rozanov, and Larry W. Thomason
Atmos. Meas. Tech., 17, 3669–3678, https://doi.org/10.5194/amt-17-3669-2024, https://doi.org/10.5194/amt-17-3669-2024, 2024
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Comparing different aerosol data sets for scientific studies often requires converting aerosol extinction data between different wavelengths. A common approximation for the spectral behavior of aerosol is the Ångström formula; however, this introduces biases. Using measurements across many different wavelengths from a single instrument, we derive an empirical relationship to both characterize this bias and offer a correction for other studies that may employ this analysis approach.
Piers M. Forster, Chris Smith, Tristram Walsh, William F. Lamb, Robin Lamboll, Bradley Hall, Mathias Hauser, Aurélien Ribes, Debbie Rosen, Nathan P. Gillett, Matthew D. Palmer, Joeri Rogelj, Karina von Schuckmann, Blair Trewin, Myles Allen, Robbie Andrew, Richard A. Betts, Alex Borger, Tim Boyer, Jiddu A. Broersma, Carlo Buontempo, Samantha Burgess, Chiara Cagnazzo, Lijing Cheng, Pierre Friedlingstein, Andrew Gettelman, Johannes Gütschow, Masayoshi Ishii, Stuart Jenkins, Xin Lan, Colin Morice, Jens Mühle, Christopher Kadow, John Kennedy, Rachel E. Killick, Paul B. Krummel, Jan C. Minx, Gunnar Myhre, Vaishali Naik, Glen P. Peters, Anna Pirani, Julia Pongratz, Carl-Friedrich Schleussner, Sonia I. Seneviratne, Sophie Szopa, Peter Thorne, Mahesh V. M. Kovilakam, Elisa Majamäki, Jukka-Pekka Jalkanen, Margreet van Marle, Rachel M. Hoesly, Robert Rohde, Dominik Schumacher, Guido van der Werf, Russell Vose, Kirsten Zickfeld, Xuebin Zhang, Valérie Masson-Delmotte, and Panmao Zhai
Earth Syst. Sci. Data, 16, 2625–2658, https://doi.org/10.5194/essd-16-2625-2024, https://doi.org/10.5194/essd-16-2625-2024, 2024
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This paper tracks some key indicators of global warming through time, from 1850 through to the end of 2023. It is designed to give an authoritative estimate of global warming to date and its causes. We find that in 2023, global warming reached 1.3 °C and is increasing at over 0.2 °C per decade. This is caused by all-time-high greenhouse gas emissions.
Malte Meinshausen, Carl-Friedrich Schleussner, Kathleen Beyer, Greg Bodeker, Olivier Boucher, Josep G. Canadell, John S. Daniel, Aïda Diongue-Niang, Fatima Driouech, Erich Fischer, Piers Forster, Michael Grose, Gerrit Hansen, Zeke Hausfather, Tatiana Ilyina, Jarmo S. Kikstra, Joyce Kimutai, Andrew D. King, June-Yi Lee, Chris Lennard, Tabea Lissner, Alexander Nauels, Glen P. Peters, Anna Pirani, Gian-Kasper Plattner, Hans Pörtner, Joeri Rogelj, Maisa Rojas, Joyashree Roy, Bjørn H. Samset, Benjamin M. Sanderson, Roland Séférian, Sonia Seneviratne, Christopher J. Smith, Sophie Szopa, Adelle Thomas, Diana Urge-Vorsatz, Guus J. M. Velders, Tokuta Yokohata, Tilo Ziehn, and Zebedee Nicholls
Geosci. Model Dev., 17, 4533–4559, https://doi.org/10.5194/gmd-17-4533-2024, https://doi.org/10.5194/gmd-17-4533-2024, 2024
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The scientific community is considering new scenarios to succeed RCPs and SSPs for the next generation of Earth system model runs to project future climate change. To contribute to that effort, we reflect on relevant policy and scientific research questions and suggest categories for representative emission pathways. These categories are tailored to the Paris Agreement long-term temperature goal, high-risk outcomes in the absence of further climate policy and worlds “that could have been”.
Zhihong Zhuo, Herman F. Fuglestvedt, Matthew Toohey, and Kirstin Krüger
Atmos. Chem. Phys., 24, 6233–6249, https://doi.org/10.5194/acp-24-6233-2024, https://doi.org/10.5194/acp-24-6233-2024, 2024
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This work simulated volcanic eruptions with varied eruption source parameters under different initial conditions with a fully coupled Earth system model. We show that initial atmospheric conditions control the meridional distribution of volcanic volatiles and modulate volcanic forcing and subsequent climate and environmental impacts of tropical and Northern Hemisphere extratropical eruptions. This highlights the potential for predicting these impacts as early as the first post-eruption month.
Jean-Paul Vernier, Thomas J. Aubry, Claudia Timmreck, Anja Schmidt, Lieven Clarisse, Fred Prata, Nicolas Theys, Andrew T. Prata, Graham Mann, Hyundeok Choi, Simon Carn, Richard Rigby, Susan C. Loughlin, and John A. Stevenson
Atmos. Chem. Phys., 24, 5765–5782, https://doi.org/10.5194/acp-24-5765-2024, https://doi.org/10.5194/acp-24-5765-2024, 2024
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The 2019 Raikoke eruption (Kamchatka, Russia) generated one of the largest emissions of particles and gases into the stratosphere since the 1991 Mt. Pinatubo eruption. The Volcano Response (VolRes) initiative, an international effort, provided a platform for the community to share information about this eruption and assess its climate impact. The eruption led to a minor global surface cooling of 0.02 °C in 2020 which is negligible relative to warming induced by human greenhouse gas emissions.
Jiwoo Lee, Peter J. Gleckler, Min-Seop Ahn, Ana Ordonez, Paul A. Ullrich, Kenneth R. Sperber, Karl E. Taylor, Yann Y. Planton, Eric Guilyardi, Paul Durack, Celine Bonfils, Mark D. Zelinka, Li-Wei Chao, Bo Dong, Charles Doutriaux, Chengzhu Zhang, Tom Vo, Jason Boutte, Michael F. Wehner, Angeline G. Pendergrass, Daehyun Kim, Zeyu Xue, Andrew T. Wittenberg, and John Krasting
Geosci. Model Dev., 17, 3919–3948, https://doi.org/10.5194/gmd-17-3919-2024, https://doi.org/10.5194/gmd-17-3919-2024, 2024
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We introduce an open-source software, the PCMDI Metrics Package (PMP), developed for a comprehensive comparison of Earth system models (ESMs) with real-world observations. Using diverse metrics evaluating climatology, variability, and extremes simulated in thousands of simulations from the Coupled Model Intercomparison Project (CMIP), PMP aids in benchmarking model improvements across generations. PMP also enables efficient tracking of performance evolutions during ESM developments.
Christina V. Brodowsky, Timofei Sukhodolov, Gabriel Chiodo, Valentina Aquila, Slimane Bekki, Sandip S. Dhomse, Michael Höpfner, Anton Laakso, Graham W. Mann, Ulrike Niemeier, Giovanni Pitari, Ilaria Quaglia, Eugene Rozanov, Anja Schmidt, Takashi Sekiya, Simone Tilmes, Claudia Timmreck, Sandro Vattioni, Daniele Visioni, Pengfei Yu, Yunqian Zhu, and Thomas Peter
Atmos. Chem. Phys., 24, 5513–5548, https://doi.org/10.5194/acp-24-5513-2024, https://doi.org/10.5194/acp-24-5513-2024, 2024
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The aerosol layer is an essential part of the climate system. We characterize the sulfur budget in a volcanically quiescent (background) setting, with a special focus on the sulfate aerosol layer using, for the first time, a multi-model approach. The aim is to identify weak points in the representation of the atmospheric sulfur budget in an intercomparison of nine state-of-the-art coupled global circulation models.
Laura Wainman, Lauren R. Marshall, and Anja Schmidt
Clim. Past, 20, 951–968, https://doi.org/10.5194/cp-20-951-2024, https://doi.org/10.5194/cp-20-951-2024, 2024
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The Mt Samalas eruption had global-scale impacts on climate and has been linked to historical events throughout latter half of the 13th century. Using model simulations and multi-proxy data, we constrain the year and season of the eruption to summer 1257 and investigate the regional-scale variability in surface cooling following the eruption. We also evaluate our model-to-proxy comparison framework and discuss current limitations of the approach.
Travis N. Knepp, Mahesh Kovilakam, Larry Thomason, and Stephen J. Miller
Atmos. Meas. Tech., 17, 2025–2054, https://doi.org/10.5194/amt-17-2025-2024, https://doi.org/10.5194/amt-17-2025-2024, 2024
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An algorithm is presented to derive a new SAGE III/ISS (Stratospheric Aerosol and Gas Experiment III on the International Space Station) Level-2 product: the size distribution of stratospheric particles. This is a significant improvement over previous techniques in that we now provide uncertainty estimates for all inferred parameters. We also evaluated the stability of this method in retrieving bimodal distribution parameters. We present a special application to the 2022 eruption of Hunga Tonga.
Nils Weitzel, Heather Andres, Jean-Philippe Baudouin, Marie-Luise Kapsch, Uwe Mikolajewicz, Lukas Jonkers, Oliver Bothe, Elisa Ziegler, Thomas Kleinen, André Paul, and Kira Rehfeld
Clim. Past, 20, 865–890, https://doi.org/10.5194/cp-20-865-2024, https://doi.org/10.5194/cp-20-865-2024, 2024
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The ability of climate models to faithfully reproduce past warming episodes is a valuable test considering potentially large future warming. We develop a new method to compare simulations of the last deglaciation with temperature reconstructions. We find that reconstructions differ more between regions than simulations, potentially due to deficiencies in the simulation design, models, or reconstructions. Our work is a promising step towards benchmarking simulations of past climate transitions.
Stephanie Fiedler, Vaishali Naik, Fiona M. O'Connor, Christopher J. Smith, Paul Griffiths, Ryan J. Kramer, Toshihiko Takemura, Robert J. Allen, Ulas Im, Matthew Kasoar, Angshuman Modak, Steven Turnock, Apostolos Voulgarakis, Duncan Watson-Parris, Daniel M. Westervelt, Laura J. Wilcox, Alcide Zhao, William J. Collins, Michael Schulz, Gunnar Myhre, and Piers M. Forster
Geosci. Model Dev., 17, 2387–2417, https://doi.org/10.5194/gmd-17-2387-2024, https://doi.org/10.5194/gmd-17-2387-2024, 2024
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Climate scientists want to better understand modern climate change. Thus, climate model experiments are performed and compared. The results of climate model experiments differ, as assessed in the latest Intergovernmental Panel on Climate Change (IPCC) assessment report. This article gives insights into the challenges and outlines opportunities for further improving the understanding of climate change. It is based on views of a group of experts in atmospheric composition–climate interactions.
Julie Christin Schindlbeck-Belo, Matthew Toohey, Marion Jegen, Steffen Kutterolf, and Kira Rehfeld
Earth Syst. Sci. Data, 16, 1063–1081, https://doi.org/10.5194/essd-16-1063-2024, https://doi.org/10.5194/essd-16-1063-2024, 2024
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Volcanic forcing of climate resulting from major explosive eruptions is a dominant natural driver of past climate variability. To support model studies of the potential impacts of explosive volcanism on climate variability across timescales, we present an ensemble reconstruction of volcanic stratospheric sulfur injection over the last 140 000 years that is based primarily on tephra records.
Hamza Ahsan, Hailong Wang, Jingbo Wu, Mingxuan Wu, Steven J. Smith, Susanne Bauer, Harrison Suchyta, Dirk Olivié, Gunnar Myhre, Hitoshi Matsui, Huisheng Bian, Jean-François Lamarque, Ken Carslaw, Larry Horowitz, Leighton Regayre, Mian Chin, Michael Schulz, Ragnhild Bieltvedt Skeie, Toshihiko Takemura, and Vaishali Naik
Atmos. Chem. Phys., 23, 14779–14799, https://doi.org/10.5194/acp-23-14779-2023, https://doi.org/10.5194/acp-23-14779-2023, 2023
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We examine the impact of the assumed effective height of SO2 injection, SO2 and BC emission seasonality, and the assumed fraction of SO2 emissions injected as SO4 on climate and chemistry model results. We find that the SO2 injection height has a large impact on surface SO2 concentrations and, in some models, radiative flux. These assumptions are a
hiddensource of inter-model variability and may be leading to bias in some climate model results.
Michael Sigmond, James Anstey, Vivek Arora, Ruth Digby, Nathan Gillett, Viatcheslav Kharin, William Merryfield, Catherine Reader, John Scinocca, Neil Swart, John Virgin, Carsten Abraham, Jason Cole, Nicolas Lambert, Woo-Sung Lee, Yongxiao Liang, Elizaveta Malinina, Landon Rieger, Knut von Salzen, Christian Seiler, Clint Seinen, Andrew Shao, Reinel Sospedra-Alfonso, Libo Wang, and Duo Yang
Geosci. Model Dev., 16, 6553–6591, https://doi.org/10.5194/gmd-16-6553-2023, https://doi.org/10.5194/gmd-16-6553-2023, 2023
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We present a new activity which aims to organize the analysis of biases in the Canadian Earth System model (CanESM) in a systematic manner. Results of this “Analysis for Development” (A4D) activity includes a new CanESM version, CanESM5.1, which features substantial improvements regarding the simulation of dust and stratospheric temperatures, a second CanESM5.1 variant with reduced climate sensitivity, and insights into potential avenues to reduce various other model biases.
Larry W. Thomason and Travis Knepp
Atmos. Chem. Phys., 23, 10361–10381, https://doi.org/10.5194/acp-23-10361-2023, https://doi.org/10.5194/acp-23-10361-2023, 2023
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We examine space-based observations of stratospheric aerosol to infer the presence of episodic smoke perturbations. We find that smoke's optical properties often show a consistent behavior but vary somewhat from event to event. We also find that the rate of smoke events observed in the 1984–2005 period is about half the rate of similar observations in the period from 2017 to the present; however, with such low overall rates, inferring change between the periods is difficult.
Felix Wrana, Ulrike Niemeier, Larry W. Thomason, Sandra Wallis, and Christian von Savigny
Atmos. Chem. Phys., 23, 9725–9743, https://doi.org/10.5194/acp-23-9725-2023, https://doi.org/10.5194/acp-23-9725-2023, 2023
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The stratospheric aerosol layer is a naturally occurring and permanent layer of aerosol, in this case very small droplets of mostly sulfuric acid and water, that has a cooling effect on our climate. To quantify this effect and for our general understanding of stratospheric microphysical processes, knowledge of the size of those aerosol particles is needed. Using satellite measurements and atmospheric models we show that some volcanic eruptions can lead to on average smaller aerosol sizes.
Yiqi Zheng, Larry W. Horowitz, Raymond Menzel, David J. Paynter, Vaishali Naik, Jingyi Li, and Jingqiu Mao
Atmos. Chem. Phys., 23, 8993–9007, https://doi.org/10.5194/acp-23-8993-2023, https://doi.org/10.5194/acp-23-8993-2023, 2023
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Biogenic secondary organic aerosols (SOAs) account for a large fraction of fine aerosol at the global scale. Using long-term measurements and a climate model, we investigate anthropogenic impacts on biogenic SOA at both decadal and centennial timescales. Results show that despite reductions in biogenic precursor emissions, SOA has been strongly amplified by anthropogenic emissions since the preindustrial era and exerts a cooling radiative forcing.
Chenwei Fang, Jim M. Haywood, Ju Liang, Ben T. Johnson, Ying Chen, and Bin Zhu
Atmos. Chem. Phys., 23, 8341–8368, https://doi.org/10.5194/acp-23-8341-2023, https://doi.org/10.5194/acp-23-8341-2023, 2023
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The responses of Asian summer monsoon duration and intensity to air pollution mitigation are identified given the net-zero future. We show that reducing scattering aerosols makes the rainy season longer and stronger across South Asia and East Asia but that absorbing aerosol reduction has the opposite effect. Our results hint at distinct monsoon responses to emission controls that target different aerosols.
Piers M. Forster, Christopher J. Smith, Tristram Walsh, William F. Lamb, Robin Lamboll, Mathias Hauser, Aurélien Ribes, Debbie Rosen, Nathan Gillett, Matthew D. Palmer, Joeri Rogelj, Karina von Schuckmann, Sonia I. Seneviratne, Blair Trewin, Xuebin Zhang, Myles Allen, Robbie Andrew, Arlene Birt, Alex Borger, Tim Boyer, Jiddu A. Broersma, Lijing Cheng, Frank Dentener, Pierre Friedlingstein, José M. Gutiérrez, Johannes Gütschow, Bradley Hall, Masayoshi Ishii, Stuart Jenkins, Xin Lan, June-Yi Lee, Colin Morice, Christopher Kadow, John Kennedy, Rachel Killick, Jan C. Minx, Vaishali Naik, Glen P. Peters, Anna Pirani, Julia Pongratz, Carl-Friedrich Schleussner, Sophie Szopa, Peter Thorne, Robert Rohde, Maisa Rojas Corradi, Dominik Schumacher, Russell Vose, Kirsten Zickfeld, Valérie Masson-Delmotte, and Panmao Zhai
Earth Syst. Sci. Data, 15, 2295–2327, https://doi.org/10.5194/essd-15-2295-2023, https://doi.org/10.5194/essd-15-2295-2023, 2023
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This is a critical decade for climate action, but there is no annual tracking of the level of human-induced warming. We build on the Intergovernmental Panel on Climate Change assessment reports that are authoritative but published infrequently to create a set of key global climate indicators that can be tracked through time. Our hope is that this becomes an important annual publication that policymakers, media, scientists and the public can refer to.
Mahesh Kovilakam, Larry Thomason, and Travis Knepp
Atmos. Meas. Tech., 16, 2709–2731, https://doi.org/10.5194/amt-16-2709-2023, https://doi.org/10.5194/amt-16-2709-2023, 2023
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The paper describes SAGE III/ISS aerosol/cloud categorization and its implications on Global Space-based Stratospheric Aerosol Climatology (GloSSAC). The presence of data from the SAGE type of multi-wavelength measurements is important in GloSSAC. The new aerosol/cloud categorization method described in this paper will help retain more measurements, particularly in the lower stratosphere during and following a volcanic event and other processes.
Lucie J. Lücke, Andrew P. Schurer, Matthew Toohey, Lauren R. Marshall, and Gabriele C. Hegerl
Clim. Past, 19, 959–978, https://doi.org/10.5194/cp-19-959-2023, https://doi.org/10.5194/cp-19-959-2023, 2023
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Evidence from tree rings and ice cores provides incomplete information about past volcanic eruptions and the Sun's activity. We model past climate with varying solar and volcanic scenarios and compare it to reconstructed temperature. We confirm that the Sun's influence was small and that uncertain volcanic activity can strongly influence temperature shortly after the eruption. On long timescales, independent data sources closely agree, increasing our confidence in understanding of past climate.
Flossie Brown, Lauren Marshall, Peter H. Haynes, Rolando R. Garcia, Thomas Birner, and Anja Schmidt
Atmos. Chem. Phys., 23, 5335–5353, https://doi.org/10.5194/acp-23-5335-2023, https://doi.org/10.5194/acp-23-5335-2023, 2023
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Large-magnitude volcanic eruptions have the potential to alter large-scale circulation patterns, such as the quasi-biennial oscillation (QBO). The QBO is an oscillation of the tropical stratospheric zonal winds between easterly and westerly directions. Using a climate model, we show that large-magnitude eruptions can delay the progression of the QBO, with a much longer delay when the shear is easterly than when it is westerly. Such delays may affect weather and transport of atmospheric gases.
Glen Chua, Vaishali Naik, and Larry Wayne Horowitz
Atmos. Chem. Phys., 23, 4955–4975, https://doi.org/10.5194/acp-23-4955-2023, https://doi.org/10.5194/acp-23-4955-2023, 2023
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The hydroxyl radical (OH) is an atmospheric
detergent, removing air pollutants and greenhouse gases like methane from the atmosphere. Thus, understanding how it is changing and responding to its various drivers is important for air quality and climate. We found that OH has increased by about 5 % globally from 1980 to 2014 in our model, mostly driven by increasing nitrogen oxide (NOx) emissions. This suggests potential climate tradeoffs from air quality policies solely targeting NOx emissions.
Susanne Baur, Alexander Nauels, Zebedee Nicholls, Benjamin M. Sanderson, and Carl-Friedrich Schleussner
Earth Syst. Dynam., 14, 367–381, https://doi.org/10.5194/esd-14-367-2023, https://doi.org/10.5194/esd-14-367-2023, 2023
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Solar radiation modification (SRM) artificially cools global temperature without acting on the cause of climate change. This study looks at how long SRM would have to be deployed to limit warming to 1.5 °C and how this timeframe is affected by different levels of mitigation, negative emissions and climate uncertainty. None of the three factors alone can guarantee short SRM deployment. Due to their uncertainty at the time of SRM initialization, any deployment risks may be several centuries long.
Christian Wirths, Elisa Ziegler, and Kira Rehfeld
EGUsphere, https://doi.org/10.5194/egusphere-2023-86, https://doi.org/10.5194/egusphere-2023-86, 2023
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We compare Holocene temperature trends from reconstructions and global climate models of different complexities. We find that models of all complexities disagree with mid-Holocene trends in reconstructions, and we show that this disagreement is largely independent of the type of reconstruction. From our results we conclude that a seasonal bias in the reconstructions is unlikely as a full explanation for the disagreement.
Jennifer Schallock, Christoph Brühl, Christine Bingen, Michael Höpfner, Landon Rieger, and Jos Lelieveld
Atmos. Chem. Phys., 23, 1169–1207, https://doi.org/10.5194/acp-23-1169-2023, https://doi.org/10.5194/acp-23-1169-2023, 2023
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We characterized the influence of volcanic aerosols for the period 1990–2019 and established a volcanic SO2 emission inventory that includes more than 500 eruptions. From limb-based satellite observations of SO2 and extinction, we derive 3D plumes of SO2 perturbations and injected mass by a novel method. We calculate instantaneous radiative forcing with a comprehensive chemisty climate model. Our results show that smaller eruptions can also contribute to the stratospheric aerosol forcing.
Jarmo S. Kikstra, Zebedee R. J. Nicholls, Christopher J. Smith, Jared Lewis, Robin D. Lamboll, Edward Byers, Marit Sandstad, Malte Meinshausen, Matthew J. Gidden, Joeri Rogelj, Elmar Kriegler, Glen P. Peters, Jan S. Fuglestvedt, Ragnhild B. Skeie, Bjørn H. Samset, Laura Wienpahl, Detlef P. van Vuuren, Kaj-Ivar van der Wijst, Alaa Al Khourdajie, Piers M. Forster, Andy Reisinger, Roberto Schaeffer, and Keywan Riahi
Geosci. Model Dev., 15, 9075–9109, https://doi.org/10.5194/gmd-15-9075-2022, https://doi.org/10.5194/gmd-15-9075-2022, 2022
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Assessing hundreds or thousands of emission scenarios in terms of their global mean temperature implications requires standardised procedures of infilling, harmonisation, and probabilistic temperature assessments. We here present the open-source
climate-assessmentworkflow that was used in the IPCC AR6 Working Group III report. The paper provides key insight for anyone wishing to understand the assessment of climate outcomes of mitigation pathways in the context of the Paris Agreement.
Johannes Quaas, Hailing Jia, Chris Smith, Anna Lea Albright, Wenche Aas, Nicolas Bellouin, Olivier Boucher, Marie Doutriaux-Boucher, Piers M. Forster, Daniel Grosvenor, Stuart Jenkins, Zbigniew Klimont, Norman G. Loeb, Xiaoyan Ma, Vaishali Naik, Fabien Paulot, Philip Stier, Martin Wild, Gunnar Myhre, and Michael Schulz
Atmos. Chem. Phys., 22, 12221–12239, https://doi.org/10.5194/acp-22-12221-2022, https://doi.org/10.5194/acp-22-12221-2022, 2022
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Pollution particles cool climate and offset part of the global warming. However, they are washed out by rain and thus their effect responds quickly to changes in emissions. We show multiple datasets to demonstrate that aerosol emissions and their concentrations declined in many regions influenced by human emissions, as did the effects on clouds. Consequently, the cooling impact on the Earth energy budget became smaller. This change in trend implies a relative warming.
Travis N. Knepp, Larry Thomason, Mahesh Kovilakam, Jason Tackett, Jayanta Kar, Robert Damadeo, and David Flittner
Atmos. Meas. Tech., 15, 5235–5260, https://doi.org/10.5194/amt-15-5235-2022, https://doi.org/10.5194/amt-15-5235-2022, 2022
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We used aerosol profiles from the SAGE III/ISS instrument to develop an aerosol classification method that was tested on four case-study events (two volcanic, two fire) and supported with CALIOP aerosol products. The method worked well in identifying smoke and volcanic aerosol in the stratosphere for these events. Raikoke is presented as a demonstration of the limitations of this method.
Qirui Zhong, Nick Schutgens, Guido van der Werf, Twan van Noije, Kostas Tsigaridis, Susanne E. Bauer, Tero Mielonen, Alf Kirkevåg, Øyvind Seland, Harri Kokkola, Ramiro Checa-Garcia, David Neubauer, Zak Kipling, Hitoshi Matsui, Paul Ginoux, Toshihiko Takemura, Philippe Le Sager, Samuel Rémy, Huisheng Bian, Mian Chin, Kai Zhang, Jialei Zhu, Svetlana G. Tsyro, Gabriele Curci, Anna Protonotariou, Ben Johnson, Joyce E. Penner, Nicolas Bellouin, Ragnhild B. Skeie, and Gunnar Myhre
Atmos. Chem. Phys., 22, 11009–11032, https://doi.org/10.5194/acp-22-11009-2022, https://doi.org/10.5194/acp-22-11009-2022, 2022
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Aerosol optical depth (AOD) errors for biomass burning aerosol (BBA) are evaluated in 18 global models against satellite datasets. Notwithstanding biases in satellite products, they allow model evaluations. We observe large and diverse model biases due to errors in BBA. Further interpretations of AOD diversities suggest large biases exist in key processes for BBA which require better constraining. These results can contribute to further model improvement and development.
Michael Sigl, Matthew Toohey, Joseph R. McConnell, Jihong Cole-Dai, and Mirko Severi
Earth Syst. Sci. Data, 14, 3167–3196, https://doi.org/10.5194/essd-14-3167-2022, https://doi.org/10.5194/essd-14-3167-2022, 2022
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Volcanism is a key driver of climate. Based on ice cores from Greenland and Antarctica, we reconstruct its climate impact potential over the Holocene. By aligning records on a well-dated chronology from Antarctica, we resolve long-standing inconsistencies in the dating of past volcanic eruptions. We reconstruct 850 eruptions (which, in total, injected 7410 Tg of sulfur in the stratosphere) and estimate how they changed the opacity of the atmosphere, a prerequisite for climate model simulations.
Helen Mackay, Gill Plunkett, Britta J. L. Jensen, Thomas J. Aubry, Christophe Corona, Woon Mi Kim, Matthew Toohey, Michael Sigl, Markus Stoffel, Kevin J. Anchukaitis, Christoph Raible, Matthew S. M. Bolton, Joseph G. Manning, Timothy P. Newfield, Nicola Di Cosmo, Francis Ludlow, Conor Kostick, Zhen Yang, Lisa Coyle McClung, Matthew Amesbury, Alistair Monteath, Paul D. M. Hughes, Pete G. Langdon, Dan Charman, Robert Booth, Kimberley L. Davies, Antony Blundell, and Graeme T. Swindles
Clim. Past, 18, 1475–1508, https://doi.org/10.5194/cp-18-1475-2022, https://doi.org/10.5194/cp-18-1475-2022, 2022
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We assess the climatic and societal impact of the 852/3 CE Alaska Mount Churchill eruption using environmental reconstructions, historical records and climate simulations. The eruption is associated with significant Northern Hemisphere summer cooling, despite having only a moderate sulfate-based climate forcing potential; however, evidence of a widespread societal response is lacking. We discuss the difficulties of confirming volcanic impacts of a single eruption even when it is precisely dated.
Charles D. Koven, Vivek K. Arora, Patricia Cadule, Rosie A. Fisher, Chris D. Jones, David M. Lawrence, Jared Lewis, Keith Lindsay, Sabine Mathesius, Malte Meinshausen, Michael Mills, Zebedee Nicholls, Benjamin M. Sanderson, Roland Séférian, Neil C. Swart, William R. Wieder, and Kirsten Zickfeld
Earth Syst. Dynam., 13, 885–909, https://doi.org/10.5194/esd-13-885-2022, https://doi.org/10.5194/esd-13-885-2022, 2022
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We explore the long-term dynamics of Earth's climate and carbon cycles under a pair of contrasting scenarios to the year 2300 using six models that include both climate and carbon cycle dynamics. One scenario assumes very high emissions, while the second assumes a peak in emissions, followed by rapid declines to net negative emissions. We show that the models generally agree that warming is roughly proportional to carbon emissions but that many other aspects of the model projections differ.
Jim M. Haywood, Andy Jones, Ben T. Johnson, and William McFarlane Smith
Atmos. Chem. Phys., 22, 6135–6150, https://doi.org/10.5194/acp-22-6135-2022, https://doi.org/10.5194/acp-22-6135-2022, 2022
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Simulations are presented investigating the influence of moderately absorbing aerosol in the stratosphere to combat the impacts of climate change. A number of detrimental impacts are noted compared to sulfate aerosol, including (i) reduced cooling efficiency, (ii) increased deficits in global precipitation, (iii) delays in the recovery of the stratospheric ozone hole, and (iv) disruption of the stratospheric circulation and the wintertime storm tracks that impact European precipitation.
Davide Zanchettin, Claudia Timmreck, Myriam Khodri, Anja Schmidt, Matthew Toohey, Manabu Abe, Slimane Bekki, Jason Cole, Shih-Wei Fang, Wuhu Feng, Gabriele Hegerl, Ben Johnson, Nicolas Lebas, Allegra N. LeGrande, Graham W. Mann, Lauren Marshall, Landon Rieger, Alan Robock, Sara Rubinetti, Kostas Tsigaridis, and Helen Weierbach
Geosci. Model Dev., 15, 2265–2292, https://doi.org/10.5194/gmd-15-2265-2022, https://doi.org/10.5194/gmd-15-2265-2022, 2022
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This paper provides metadata and first analyses of the volc-pinatubo-full experiment of CMIP6-VolMIP. Results from six Earth system models reveal significant differences in radiative flux anomalies that trace back to different implementations of volcanic forcing. Surface responses are in contrast overall consistent across models, reflecting the large spread due to internal variability. A second phase of VolMIP shall consider both aspects toward improved protocol for volc-pinatubo-full.
Lea Beusch, Zebedee Nicholls, Lukas Gudmundsson, Mathias Hauser, Malte Meinshausen, and Sonia I. Seneviratne
Geosci. Model Dev., 15, 2085–2103, https://doi.org/10.5194/gmd-15-2085-2022, https://doi.org/10.5194/gmd-15-2085-2022, 2022
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We introduce the first chain of computationally efficient Earth system model (ESM) emulators to translate user-defined greenhouse gas emission pathways into regional temperature change time series accounting for all major sources of climate change projection uncertainty. By combining the global mean emulator MAGICC with the spatially resolved emulator MESMER, we can derive ESM-specific and constrained probabilistic emulations to rapidly provide targeted climate information at the local scale.
Gill Plunkett, Michael Sigl, Hans F. Schwaiger, Emma L. Tomlinson, Matthew Toohey, Joseph R. McConnell, Jonathan R. Pilcher, Takeshi Hasegawa, and Claus Siebe
Clim. Past, 18, 45–65, https://doi.org/10.5194/cp-18-45-2022, https://doi.org/10.5194/cp-18-45-2022, 2022
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We report the identification of volcanic ash associated with a sulfate layer in Greenland ice cores previously thought to have been from the Vesuvius 79 CE eruption and which had been used to confirm the precise dating of the Greenland ice-core chronology. We find that the tephra was probably produced by an eruption in Alaska. We show the importance of verifying sources of volcanic signals in ice cores through ash analysis to avoid errors in dating ice cores and interpreting volcanic impacts.
Anne Dallmeyer, Martin Claussen, Stephan J. Lorenz, Michael Sigl, Matthew Toohey, and Ulrike Herzschuh
Clim. Past, 17, 2481–2513, https://doi.org/10.5194/cp-17-2481-2021, https://doi.org/10.5194/cp-17-2481-2021, 2021
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Using the comprehensive Earth system model, MPI-ESM1.2, we explore the global Holocene vegetation changes and interpret them in terms of the Holocene climate change. The model results reveal that most of the Holocene vegetation transitions seen outside the high northern latitudes can be attributed to modifications in the intensity of the global summer monsoons.
Anthony C. Jones, Adrian Hill, Samuel Remy, N. Luke Abraham, Mohit Dalvi, Catherine Hardacre, Alan J. Hewitt, Ben Johnson, Jane P. Mulcahy, and Steven T. Turnock
Atmos. Chem. Phys., 21, 15901–15927, https://doi.org/10.5194/acp-21-15901-2021, https://doi.org/10.5194/acp-21-15901-2021, 2021
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Ammonium nitrate is hard to model because it forms and evaporates rapidly. One approach is to relate its equilibrium concentration to temperature, humidity, and the amount of nitric acid and ammonia gases. Using this approach, we limit the rate at which equilibrium is reached using various condensation rates in a climate model. We show that ammonium nitrate concentrations are highly sensitive to the condensation rate. Our results will help improve the representation of nitrate in climate models.
Trevor J. McDougall, Paul M. Barker, Ryan M. Holmes, Rich Pawlowicz, Stephen M. Griffies, and Paul J. Durack
Geosci. Model Dev., 14, 6445–6466, https://doi.org/10.5194/gmd-14-6445-2021, https://doi.org/10.5194/gmd-14-6445-2021, 2021
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We show that the way that the air–sea heat flux is treated in ocean models means that the model's temperature variable should be interpreted as being Conservative Temperature, irrespective of whether the equation of state used in an ocean model is EOS-80 or TEOS-10.
Claudia Timmreck, Matthew Toohey, Davide Zanchettin, Stefan Brönnimann, Elin Lundstad, and Rob Wilson
Clim. Past, 17, 1455–1482, https://doi.org/10.5194/cp-17-1455-2021, https://doi.org/10.5194/cp-17-1455-2021, 2021
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The 1809 eruption is one of the most recent unidentified volcanic eruptions with a global climate impact. We demonstrate that climate model simulations of the 1809 eruption show generally good agreement with many large-scale temperature reconstructions and early instrumental records for a range of radiative forcing estimates. In terms of explaining the spatially heterogeneous and temporally delayed Northern Hemisphere cooling suggested by tree-ring networks, the investigation remains open.
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Short summary
Climate forcings, such as solar radiation or anthropogenic greenhouse gases, are required to run global climate model simulations. Stratospheric aerosols, which mostly originate from large volcanic eruptions, are a key natural forcing. In this paper, we document the stratospheric aerosol forcing dataset that will feed the next generation (CMIP7) of climate models. Our dataset is very different from its predecessor (CMIP6), which might affect simulations of the 1850–2021 climate.
Climate forcings, such as solar radiation or anthropogenic greenhouse gases, are required to run...