154 results on '"Robock, A"'
Search Results
2. Future Geoengineering Scenarios: Balancing Policy Relevance and Scientific Significance
- Author
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Daniele Visioni and Alan Robock
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Atmospheric Science - Published
- 2022
3. Opinion: The Scientific and Community-Building Roles of the Geoengineering Model Intercomparison Project (GeoMIP) - Past, Present, and Future
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Daniele Visioni, Ben Kravitz, Alan Robock, Simone Tilmes, Jim M. Haywood, Olivier Boucher, Mark Lawrence, Peter Irvine, Ulrike Niemeier, Lili Xia, Gabriel Chiodo, Chris Lennard, Shingo Watanabe, John C. Moore, and Helene Muri
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Klimamodellering ,Climate modelling ,Atmospheric Science ,Klimaendringer ,Geofag: 450 [VDP] ,Climate change ,Geosciences: 450 [VDP] ,Geoengineering - Abstract
The Geoengineering Model Intercomparison Project (GeoMIP) is a coordinating framework, started in 2010, that includes a series of standardized climate model experiments aimed at understanding the physical processes and projected impacts of solar geoengineering. Numerous experiments have been conducted, and numerous more have been proposed as “test-bed” experiments, spanning a variety of geoengineering techniques aimed at modifying the planetary radiation budget: stratospheric aerosol injection, marine cloud brightening, surface albedo modification, cirrus cloud thinning, and sunshade mirrors. To date, more than 100 studies have been published that used results from GeoMIP simulations. Here we provide a critical assessment of GeoMIP and its experiments. We discuss its successes and missed opportunities, for instance in terms of which experiments elicited more interest from the scientific community and which did not, and the potential reasons why that happened. We also discuss the knowledge that GeoMIP has contributed to the field of geoengineering research and climate science as a whole: what have we learned in terms of intermodel differences, robustness of the projected outcomes for specific geoengineering methods, and future areas of model development that would be necessary in the future? We also offer multiple examples of cases where GeoMIP experiments were fundamental for international assessments of climate change. Finally, we provide a series of recommendations, regarding both future experiments and more general activities, with the goal of continuously deepening our understanding of the effects of potential geoengineering approaches and reducing uncertainties in climate outcomes, important for assessing wider impacts on societies and ecosystems. In doing so, we refine the purpose of GeoMIP and outline a series of criteria whereby GeoMIP can best serve its participants, stakeholders, and the broader science community., Atmospheric Chemistry and Physics, 23 (9), ISSN:1680-7375, ISSN:1680-7367
- Published
- 2022
4. The Road toward Process-Level Understanding of Solar Geoengineering through a Multimodel Intercomparison
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Ben Kravitz, Alan Robock, and Douglas G. MacMartin
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Atmospheric Science ,business.industry ,Process (engineering) ,Systems engineering ,Environmental science ,Geoengineering ,business - Published
- 2020
5. Can stratospheric geoengineering alleviate global warming-induced changes in deciduous fruit cultivation? The case of Himachal Pradesh (India)
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Jyoti Singh, Sandeep Sahany, and Alan Robock
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Atmospheric Science ,Global and Planetary Change ,010504 meteorology & atmospheric sciences ,0208 environmental biotechnology ,Global warming ,Growing season ,Representative Concentration Pathways ,02 engineering and technology ,Forcing (mathematics) ,Radiative forcing ,Atmospheric sciences ,01 natural sciences ,020801 environmental engineering ,Deciduous ,Effects of global warming ,Environmental science ,Global environmental analysis ,0105 earth and related environmental sciences - Abstract
Using Hadley Global Environment Model 2 - Earth System and Max Planck Institute Earth System Model simulations, we assess the impact of global warming and stratospheric geoengineering on deciduous fruit production in Himachal Pradesh (the second-largest apple-producing state in India). The impacts have been assessed for the Representative Concentration Pathways 4.5 (RCP4.5) global warming scenario, and a corresponding geoengineered scenario (G3) from the Geoengineering Model Intercomparison Project, in which stratospheric aerosols are increased for 50 years from 2020 through 2069 to balance the global warming radiative forcing, and then aerosol precursor emissions are terminated. We used the period 2055–2069 (with the largest geoengineering forcing) and the period 2075–2089 (beginning 5 years into the termination phase) and evaluated winter chill and growing season heat accumulation. We found that although stratospheric geoengineering would be able to suppress the increase in temperature under an RCP4.5 scenario to some extent during both switch-on and switch-off periods, if the geoengineering was terminated, the rate of temperature increase would be higher than RCP4.5. The agroclimatically suitable area is projected to shift northeastwards (to higher elevations) under RCP4.5 as well as G3 during both periods. However, during the switched on period, geoengineering would restrict the shift, and areas of Shimla and Mandi districts (most suitable under the current climate) would not be lost due to global warming. Even during the switched off period, before the climate returned to RCP4.5 levels, the above areas would, although to a lesser extent, have reduced harmful climate effects from global warming. However, the area of suitable land (the intersection of soil and agroclimatic suitability) would decrease in both periods for RCP4.5 as well as G3, because as more high-elevation regions become agroclimatically suitable, they do not have suitable soils to support cultivation. Geoengineering could benefit deciduous fruit production by reducing the intensity of global warming; however, if geoengineering was terminated abruptly, the rate of change in temperature would be quite high. This could lead to a rapid change in land suitability and might result in total crop failure in a shorter period compared to RCP4.5.
- Published
- 2020
6. Comment on 'Climate Impact of a Regional Nuclear Weapon Exchange: An Improved Assessment Based on Detailed Source Calculations' by Reisner et al
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Alan Robock, Owen B. Toon, and Charles G. Bardeen
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Atmospheric Science ,Geophysics ,Nuclear winter ,Space and Planetary Science ,Climate impact ,Climatology ,Earth and Planetary Sciences (miscellaneous) ,Environmental science ,Nuclear weapon - Published
- 2019
7. Extreme Ozone Loss Following Nuclear War Results in Enhanced Surface Ultraviolet Radiation
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Nicole S. Lovenduski, Kim J. N. Scherrer, Charles G. Bardeen, Alan Robock, Francis Vitt, Owen B. Toon, Douglas E. Kinnison, Margot Clyne, Jonas Jägermeyr, Lili Xia, and Michael J. Mills
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Smoke ,Atmospheric Science ,chemistry.chemical_compound ,Geophysics ,Ozone ,chemistry ,Space and Planetary Science ,Earth and Planetary Sciences (miscellaneous) ,Environmental science ,Photochemistry ,Ultraviolet radiation - Published
- 2021
8. The Influence of Stratospheric Soot and Sulfate Aerosols on the Northern Hemisphere Wintertime Atmospheric Circulation
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Joshua Coupe and Alan Robock
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Atmospheric Science ,Atmospheric circulation ,Northern Hemisphere ,Atmospheric sciences ,medicine.disease_cause ,Soot ,chemistry.chemical_compound ,Geophysics ,Nuclear winter ,Arctic oscillation ,chemistry ,Space and Planetary Science ,North Atlantic oscillation ,Polar vortex ,Earth and Planetary Sciences (miscellaneous) ,medicine ,Environmental science ,Sulfate - Published
- 2021
9. New Frontiers in Geoengineering Research
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Alan Robock, John C. Moore, and Ben Kravitz
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Atmospheric Science ,business.industry ,Political science ,Geoengineering ,business - Published
- 2020
10. Nuclear Winter Responses to Nuclear War Between the United States and Russia in the Whole Atmosphere Community Climate Model Version 4 and the Goddard Institute for Space Studies ModelE
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Charles G. Bardeen, Joshua Coupe, Owen B. Toon, and Alan Robock
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Atmosphere ,Atmospheric Science ,Geophysics ,Nuclear winter ,Space and Planetary Science ,Climatology ,Earth and Planetary Sciences (miscellaneous) ,Climate change ,Environmental science ,Climate model ,Space (mathematics) ,Global cooling - Published
- 2019
11. Modeling the 1783–1784 Laki Eruption in Iceland: 1. Aerosol Evolution and Global Stratospheric Circulation Impacts
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Brian Zambri, Anja Schmidt, Alan Robock, and Michael J. Mills
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Atmospheric Science ,Geophysics ,Circulation (fluid dynamics) ,Space and Planetary Science ,Climatology ,Earth and Planetary Sciences (miscellaneous) ,Environmental science ,Climate model ,Aerosol - Published
- 2019
12. Modeling the 1783–1784 Laki Eruption in Iceland: 2. Climate Impacts
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Brian Zambri, Alan Robock, Michael J. Mills, and Anja Schmidt
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Atmospheric Science ,Geophysics ,Space and Planetary Science ,Climatology ,Earth and Planetary Sciences (miscellaneous) ,Environmental science ,Climate model - Published
- 2019
13. Constrained simulation of aerosol species and sources during pre-monsoon season over the Indian subcontinent
- Author
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Kravitz, Ben, Rasch, Philip, Wang, Hailong, Robock, Alan, Gabriel, Corey, Cole, Jason, Haywood, Jim, Ji, Duoying, Jones, Andy, Lenton, Andrew, Moore, John, Muri, Helene, Niemeier, Ulrike, Phipps, Steven, Schmidt, Hauke, Watanabe, Shingo, Yang, Shuting, Yoon, Jin-Ho, Bharath Kumar, D., Verma, Shubha, Boucher, Olivier, Wang, Rong, Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory (PNNL), Pacific NW Natl Lab, Richland, WA 99352 USA, Laboratory of Microbial Technology, Shandong University, Department of Environmental Sciences [New Brunswick], School of Environmental and Biological Sciences [New Brunswick], Rutgers, The State University of New Jersey [New Brunswick] (RU), Rutgers University System (Rutgers)-Rutgers University System (Rutgers)-Rutgers, The State University of New Jersey [New Brunswick] (RU), Rutgers University System (Rutgers)-Rutgers University System (Rutgers), Blackett Laboratory, Imperial College London, University of Exeter, State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Met Office Hadley Centre (MOHC), United Kingdom Met Office [Exeter], CISRO Oceans and Atmosphere [Hobart], Robarts Research Institute [Canada], University of Western Ontario (UWO), Department of Geosciences [Oslo], Faculty of Mathematics and Natural Sciences [Oslo], University of Oslo (UiO)-University of Oslo (UiO), Max Planck Institute for Meteorology (MPI-M), Max-Planck-Gesellschaft, University of New South Wales [Sydney] (UNSW), Max-Planck-Institut für Meteorologie (MPI-M), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Danish Meteorological Institute (DMI), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Beijing Normal University (BNU), Met Office Hadley Centre for Climate Change (MOHC), CISRO Oceans and Atmosphere, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and École normale supérieure - Paris (ENS-PSL)
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Total organic carbon ,Atmospheric Science ,010504 meteorology & atmospheric sciences ,010501 environmental sciences ,Spatial distribution ,Atmospheric sciences ,01 natural sciences ,Aerosol ,Indian subcontinent ,Pre monsoon ,[SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology ,[SDU]Sciences of the Universe [physics] ,13. Climate action ,[SDE]Environmental Sciences ,Environmental science ,Mass concentration (chemistry) ,Emission inventory ,Bay ,ComputingMilieux_MISCELLANEOUS ,0105 earth and related environmental sciences - Abstract
This study was designed to deliver a better concurrence between model estimates and observations, of atmospheric aerosol species, and predict their spatial distribution as consistently as possible. A free running aerosol simulation ( freesimu ) in a general circulation model (GCM) was performed, and further the simulated aerosol optical depth (AOD) was constrained with the observed AOD. The present study was carried out during the pre-monsoon season and for the Tigerz experiment which was conducted at stations over the Indo-Gangetic plain (IGP) and the Himalayan foot-hills in northern India. Our formulation of the constrained aerosol simulation ( constrsimu ) was based upon an identification of the freesimu with the most consistent estimates of aerosol characteristic among the three freesimu . The three freesimu (differing in source of emissions and model horizontal resolution) were carried out with the general circulation model (GCM) of Laboratoire de Meteorologie Dynamique (LMD-ZT GCM). Black carbon (BC), organic carbon (OC), and sulfate-other water soluble (Sul-ows) estimated from constrsimu amounted to 70%–100% compared to that from freesimu being 20%–50% of their measured counterparts. Among the aerosol species, the pre-monsoon mean concentration of dust was considerably high over most part of the Indian subcontinent; the anthropogenic aerosol species were, however, specifically predominant over the IGP (mostly 8–12 μ g m −3 for Sul-ows, OC). The constrsimu estimated total submicron aerosol mass concentration revealed its alarmingly high value over the northern and north-western India (> 100 μ g m −3 and as high as 300 μ g m −3 ). While the high value of observed AOD was found being mainly due to dust (AOD due to dust greater than 0.3) over the northern–northwestern IGP, it was due to Sul-ows (AOD due to Sul-ows as high as 0.4) over the eastern IGP, eastern coastline, and the Bay of Bengal. Temporal trend of fine (FM) and coarse mode (CM) AOD from constrsimu estimates and that derived from Tigerz experiment were in phase with each other for most of the days and exhibited a strong positive correlation coefficient. Source of Tigerz aerosols was mainly due to a predominant influence of dust from Africa/west Asia followed by that from northwest India, and of anthropogenic emissions originating in the IGP. A 200% increase was inferred for potential black carbon emissions (using India emission inventory implemented in a GCM) to obtain a concurrence between observed and freesimu BC concentration.
- Published
- 2018
14. Robust winter warming over Eurasia under stratospheric sulfate geoengineering – the role of stratospheric dynamics
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Amy H. Butler, Isla R. Simpson, Lantao Sun, Lorenzo M. Polvani, Alan Robock, and Antara Banerjee
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Atmospheric Science ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Physics ,QC1-999 ,Context (language use) ,010502 geochemistry & geophysics ,01 natural sciences ,Chemistry ,chemistry.chemical_compound ,Arctic oscillation ,chemistry ,Volcano ,North Atlantic oscillation ,Climatology ,Greenhouse gas ,Environmental science ,Sulfate aerosol ,Precipitation ,QD1-999 ,Stratosphere ,0105 earth and related environmental sciences - Abstract
It has been suggested that increased stratospheric sulfate aerosol loadings following large, low latitude volcanic eruptions can lead to wintertime warming over Eurasia through dynamical stratosphere-troposphere coupling. We here investigate the proposed connection in the context of hypothetical future stratospheric sulfate geoengineering in the Geoengineering Large Ensemble simulations. In those geoengineering simulations, we find that stratospheric circulation anomalies that resemble the positive phase of the Northern Annular Mode in winter is a distinguishing climate response which is absent when increasing greenhouse gases alone are prescribed. This stratospheric dynamical response projects onto the positive phase of the North Atlantic Oscillation, leading to associated side-effects of this climate intervention strategy, such as continental Eurasian warming and precipitation changes. Seasonality is a key signature of the dynamically-driven surface response. We find an opposite response of the North Atlantic Oscillation in summer, when no dynamical role of the stratosphere is expected. The robustness of the wintertime forced response stands in contrast to previously proposed volcanic responses.
- Published
- 2020
15. North Atlantic Oscillation response in GeoMIP experiments G6solar and G6sulfur: why detailed modelling is needed for understanding regional implications of solar radiation management
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Simone Tilmes, Andrew Jones, A. Jones, Ben Kravitz, Alan Robock, and Jim Haywood
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Atmospheric Science ,Solar constant ,010504 meteorology & atmospheric sciences ,Global temperature ,Global warming ,0207 environmental engineering ,Northern Hemisphere ,Climate change ,02 engineering and technology ,01 natural sciences ,lcsh:QC1-999 ,lcsh:Chemistry ,chemistry.chemical_compound ,lcsh:QD1-999 ,chemistry ,13. Climate action ,Solar radiation management ,North Atlantic oscillation ,Climatology ,Environmental science ,Sulfate aerosol ,020701 environmental engineering ,lcsh:Physics ,0105 earth and related environmental sciences - Abstract
The realization of the difficulty of limiting global-mean temperatures to within 1.5 or 2.0 ∘C above pre-industrial levels stipulated by the 21st Conference of Parties in Paris has led to increased interest in solar radiation management (SRM) techniques. Proposed SRM schemes aim to increase planetary albedo to reflect more sunlight back to space and induce a cooling that acts to partially offset global warming. Under the auspices of the Geoengineering Model Intercomparison Project, we have performed model experiments whereby global temperature under the high-forcing SSP5-8.5 scenario is reduced to follow that of the medium-forcing SSP2-4.5 scenario. Two different mechanisms to achieve this are employed: the first via a reduction in the solar constant (experiment G6solar) and the second via modelling injections of sulfur dioxide (experiment G6sulfur) which forms sulfate aerosol in the stratosphere. Results from two state-of-the-art coupled Earth system models (UKESM1 and CESM2-WACCM6) both show an impact on the North Atlantic Oscillation (NAO) in G6sulfur but not in G6solar. Both models show a persistent positive anomaly in the NAO during the Northern Hemisphere winter season in G6sulfur, suggesting an increase in zonal flow and an increase in North Atlantic storm track activity impacting the Eurasian continent and leading to high-latitude warming over Europe and Asia. These results are broadly consistent with previous findings which show similar impacts from stratospheric volcanic aerosol on the NAO and emphasize that detailed modelling of geoengineering processes is required if accurate impacts of SRM effects are to be simulated. Differences remain between the two models in predicting regional changes over the continental USA and Africa, suggesting that more models need to perform such simulations before attempting to draw any conclusions regarding potential continental-scale climate change under SRM.
- Published
- 2020
16. Model physics and chemistry causing intermodel disagreement within the VolMIP-Tambora Interactive Stratospheric Aerosol ensemble
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M. Clyne, J.-F. Lamarque, M. J. Mills, M. Khodri, W. Ball, S. Bekki, S. S. Dhomse, N. Lebas, G. Mann, L. Marshall, U. Niemeier, V. Poulain, A. Robock, E. Rozanov, A. Schmidt, A. Stenke, T. Sukhodolov, C. Timmreck, M. Toohey, F. Tummon, D. Zanchettin, Y. Zhu, O. B. Toon, Department of Atmospheric and Oceanic Sciences [Boulder] (ATOC), University of Colorado [Boulder], Laboratory for Atmospheric and Space Physics [Boulder] (LASP), National Center for Atmospheric Research [Boulder] (NCAR), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center (PMOD/WRC), Institute for Atmospheric and Climate Science [Zürich] (IAC), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Department of Geoscience and Remote Sensing [Delft], Delft University of Technology (TU Delft), STRATO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), School of Earth and Environment [Leeds] (SEE), University of Leeds, National Centre for Atmospheric Science [Leeds] (NCAS), Natural Environment Research Council (NERC), Department of Chemistry [Cambridge, UK], University of Cambridge [UK] (CAM), Max-Planck-Institut für Meteorologie (MPI-M), Max-Planck-Gesellschaft, Department of Environmental Sciences [New Brunswick], School of Environmental and Biological Sciences [New Brunswick], Rutgers, The State University of New Jersey [New Brunswick] (RU), Rutgers University System (Rutgers)-Rutgers University System (Rutgers)-Rutgers, The State University of New Jersey [New Brunswick] (RU), Rutgers University System (Rutgers)-Rutgers University System (Rutgers), Department of Geography [Cambridge, UK], Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Institute of Space and Atmospheric Studies [Saskatoon] (ISAS), Department of Physics and Engineering Physics [Saskatoon], University of Saskatchewan [Saskatoon] (U of S)-University of Saskatchewan [Saskatoon] (U of S), Federal Office of Meteorology and Climatology MeteoSwiss, Department of Environmental Sciences, Informatics and Statistics [Venezia], University of Ca’ Foscari [Venice, Italy], European Project: 603557,EC:FP7:ENV,FP7-ENV-2013-two-stage,STRATOCLIM(2013), Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), This research has been supported by the National Science Foundation (grant nos. PLR1643701 and AGS-1430051), the Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (grant nos. 20F121_138017, 200021_169241, and 200020_182239), the Deutsche Forschungsgemeinschaft (grant nos. TO 967/1-1 and FOR2820), the Seventh Framework Programme (grant no. STRATOCLIM (603557)), the Centre National d'Etudes Spatiales (grant no. SOLSPEC), and the Natural Environment Research Council (grant nos. NE/N006038/1, NE/S000887/1 and NE/N018001/1)., Océan et variabilité du climat (VARCLIM), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Atmospheric Science ,010504 meteorology & atmospheric sciences ,Settore GEO/12 - Oceanografia e Fisica dell'Atmosfera ,010502 geochemistry & geophysics ,Atmospheric sciences ,01 natural sciences ,lcsh:Chemistry ,chemistry.chemical_compound ,Sulfate ,0105 earth and related environmental sciences ,Physics ,Effective radius ,[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph] ,geography ,Vulcanian eruption ,geography.geographical_feature_category ,Chemistry ,Grid cell ,Radiative forcing ,lcsh:QC1-999 ,Aerosol ,lcsh:QD1-999 ,Volcano ,13. Climate action ,Climate model ,lcsh:Physics - Abstract
As part of the Model Intercomparison Project on the climatic response to Volcanic forcing (VolMIP), several climate modeling centers performed a coordinated pre-study experiment with interactive stratospheric aerosol models simulating the volcanic aerosol cloud from an eruption resembling the 1815 Mt. Tambora eruption (VolMIP-Tambora ISA ensemble). The pre-study provided the ancillary ability to assess intermodel diversity in the radiative forcing for a large stratospheric-injecting equatorial eruption when the volcanic aerosol cloud is simulated interactively. An initial analysis of the VolMIP-Tambora ISA ensemble showed large disparities between models in the stratospheric global mean aerosol optical depth (AOD). In this study, we now show that stratospheric global mean AOD differences among the participating models are primarily due to differences in aerosol size, which we track here by effective radius. We identify specific physical and chemical processes that are missing in some models and/or parameterized differently between models, which are together causing the differences in effective radius. In particular, our analysis indicates that interactively tracking hydroxyl radical (OH) chemistry following a large volcanic injection of sulfur dioxide (SO2) is an important factor in allowing for the timescale for sulfate formation to be properly simulated. In addition, depending on the timescale of sulfate formation, there can be a large difference in effective radius and subsequently AOD that results from whether the SO2 is injected in a single model grid cell near the location of the volcanic eruption, or whether it is injected as a longitudinally averaged band around the Earth.
- Published
- 2020
17. The climate effects of increasing ocean albedo: an idealized representation of solar geoengineering
- Author
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Jin-Ho Yoon, C. J. Gabriel, Helene Muri, John C. Moore, Andrew Lenton, Duoying Ji, Shuting Yang, Alan Robock, Jim Haywood, Jason N. S. Cole, Hauke Schmidt, Hailong Wang, Shingo Watanabe, Ben Kravitz, Ulrike Niemeier, Philip J. Rasch, Andrew Jones, Olivier Boucher, and Steven J. Phipps
- Subjects
Atmospheric Science ,010504 meteorology & atmospheric sciences ,0208 environmental biotechnology ,Climate change ,02 engineering and technology ,Forcing (mathematics) ,Atmospheric sciences ,01 natural sciences ,Geoengineering ,Climate models ,lcsh:Chemistry ,Radiative flux ,Water cycle ,0105 earth and related environmental sciences ,Global warming ,Albedo ,Meteorology: 453 [VDP] ,Klimamodeller ,lcsh:QC1-999 ,020801 environmental engineering ,Klimaendringer ,lcsh:QD1-999 ,Meteorologi: 453 [VDP] ,Environmental science ,Climate model ,Ocean heat content ,lcsh:Physics - Abstract
Geoengineering, or climate intervention, describes methods of deliberately altering the climate system to offset anthropogenic climate change. As an idealized representation of near-surface solar geoengineering over the ocean, such as marine cloud brightening, this paper discusses experiment G1ocean-albedo of the Geoengineering Model Intercomparison Project (GeoMIP), involving an abrupt quadrupling of the CO2 concentration and an instantaneous increase in ocean albedo to maintain approximate net top-of-atmosphere radiative flux balance. A total of 11 Earth system models are relatively consistent in their temperature, radiative flux, and hydrological cycle responses to this experiment. Due to the imposed forcing, air over the land surface warms by a model average of 1.14 K, while air over most of the ocean cools. Some parts of the near-surface air temperature over ocean warm due to heat transport from land to ocean. These changes generally resolve within a few years, indicating that changes in ocean heat content play at most a small role in the warming over the oceans. The hydrological cycle response is a general slowing down, with high heterogeneity in the response, particularly in the tropics. While idealized, these results have important implications for marine cloud brightening, or other methods of geoengineering involving spatially heterogeneous forcing, or other general forcings with a strong land–ocean contrast. It also reinforces previous findings that keeping top-of-atmosphere net radiative flux constant is not sufficient for preventing changes in global mean temperature. © Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License.
- Published
- 2018
18. The Sky in Edvard Munch’s The Scream
- Author
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Alan Robock, Richard Hamblyn, and Fred Prata
- Subjects
Atmospheric Science ,010504 meteorology & atmospheric sciences ,media_common.quotation_subject ,Astronomy ,Color analysis ,02 engineering and technology ,Art ,01 natural sciences ,Similarity (network science) ,Sky ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,0105 earth and related environmental sciences ,media_common - Abstract
The Scream is a well-known painting by Edvard Munch (1863–1944). The Norwegian word used by Munch is “skrik,” which can be translated as “shriek” or “scream.” The Scream may be of interest to meteorologists because of the quite striking representation of the sky. It has been suggested that the dramatic red-colored sky was inspired by a volcanic sunset seen by Munch after the Krakatau eruption in 1883 and by a sighting of stratospheric nacreous clouds, and also that it is part of the artist’s expression of a scream from nature. The evidence for the volcanic sunset theory and Munch’s psyche are briefly reviewed. We provide support that Munch’s inspiration may have been from a sighting of nacreous clouds, observable from southern Norway during the winter months. We show that the colors and patterns of the sky in Munch’s painting match the sunset colors better if nacreous clouds are present. Their sudden appearance around and after sunset creates an impressive and dramatic effect. By comparing the color content of photographs and paintings of regular sunsets, volcanic sunsets, and nacreous clouds after sunset with the color content of the sky in The Scream, the match is better with nacreous clouds present. If this conjecture is correct, then Munch’s sky in The Scream represents one of the earliest visual documentations of a nacreous cloud display.
- Published
- 2018
19. Impact of Volcanic Eruptions on Decadal to Centennial Fluctuations of Arctic Sea Ice Extent during the Last Millennium and on Initiation of the Little Ice Age
- Author
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Joanna Slawinska and Alan Robock
- Subjects
Arctic sea ice decline ,Atmospheric Science ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,010502 geochemistry & geophysics ,01 natural sciences ,Arctic ice pack ,Arctic geoengineering ,Oceanography ,Climatology ,Atlantic multidecadal oscillation ,Sea ice ,Cryosphere ,Climate model ,Ice sheet ,Geology ,0105 earth and related environmental sciences - Abstract
This study evaluates different hypotheses of the origin of the Little Ice Age, focusing on the long-term response of Arctic sea ice and oceanic circulation to solar and volcanic perturbations. The authors analyze the Last Millennium Ensemble of climate model simulations carried out with the Community Earth System Model at the National Center for Atmospheric Research. The authors examine the duration and strength of volcanic perturbations, and the effects of initial and boundary conditions, such as the phase of the Atlantic multidecadal oscillation. They evaluate the impacts of these factors on decadal-to-multicentennial perturbations of the cryospheric, oceanic, and atmospheric components of the climate system. The authors show that, at least in the Last Millennium Ensemble, volcanic eruptions are followed by a decadal-scale positive response of the Atlantic multidecadal overturning circulation, followed by a centennial-scale enhancement of the Northern Hemispheric sea ice extent. It is hypothesized that a few mechanisms, not just one, may have to play a role in consistently explaining such a simulated climate response at both decadal and centennial time scales. The authors argue that large volcanic forcing is necessary to explain the origin and duration of Little Ice Age–like perturbations in the Last Millennium Ensemble. Other forcings might play a role as well. In particular, prolonged fluctuations in solar irradiance associated with solar minima potentially amplify the enhancement of the magnitude of volcanically triggered anomalies of Arctic sea ice extent.
- Published
- 2018
20. How well does the European Centre for Medium-Range Weather Forecasting Interim Reanalysis represent the surface air temperature in Cuban weather stations?
- Author
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Alan Robock, Albeht Rodriguez-Vega, Michel D. S. Mesquita, Odd Helge Otterå, Juan Antuña-Marrero, and Thomas Toniazzo
- Subjects
Atmospheric Science ,010504 meteorology & atmospheric sciences ,Meteorology ,Mean squared error ,0208 environmental biotechnology ,Weather forecasting ,Scale (descriptive set theory) ,02 engineering and technology ,computer.software_genre ,01 natural sciences ,020801 environmental engineering ,Weather station ,La Niña ,Data assimilation ,Altitude ,Climatology ,Range (statistics) ,Environmental science ,computer ,0105 earth and related environmental sciences - Abstract
In this research, we compare 2-m air temperature from the ERA-Interim reanalysis of the European Centre for Medium-Range Weather Forecasting with 2-m air temperature weather station observations in Cuba, with the goal of evaluating the behaviour and uncertainties of the ERA-Interim data set with respect to station-based observations. Three interpolation methods are used to determine 2-m temperatures from the ERA-Interim data set at the station locations. The differences were analysed utilizing root mean square error (RMSE), mean absolute error (MAE) and bias. The comparison was conducted for daily, monthly and annual time scales, and for the rainy (May–October) and less rainy (November–April) seasons. The best interpolation method is the mean of four grid points method. We find a warm bias in the ERA-Interim reanalysis for most Cuban stations. The smallest differences are at 1800 UTC and the largest differences are at 1200 UTC. All differences are greater than 0.3 K, although many of the stations show differences in the range of 1.5–2.0 K. In some stations the differences are greater than 5.0 K. At the daily scale more than 50% of the stations show significant differences at the 95% confidence level. The differences are caused by the altitude difference between the stations and the nearest grid point of ERA-Interim, the land-sea mask of ERA-Interim and the station location respect to this mask, and by local processes, such as a local breeze. At the monthly scale there are fewer stations with significant differences than for the other time scales. The ERA-Interim reanalysis better represents the surface 2-m temperature for coastal stations than for inland stations. Years with moderate and strong El Nino or La Nina show significant differences between ERA-Interim and observations. The amplitude between the maximum bias and the minimum bias is greater in those years.
- Published
- 2017
21. Northern Hemisphere winter warming and summer monsoon reduction after volcanic eruptions over the last millennium
- Author
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Alan Robock, Brian Zambri, Joanna Slawinska, and Allegra N. LeGrande
- Subjects
Atmospheric Science ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Northern Hemisphere ,010502 geochemistry & geophysics ,Monsoon ,01 natural sciences ,Article ,Geophysics ,Volcano ,Space and Planetary Science ,Polar vortex ,Climatology ,Paleoclimatology ,Earth and Planetary Sciences (miscellaneous) ,Environmental science ,Climate model ,Precipitation ,Stratosphere ,0105 earth and related environmental sciences - Abstract
Observations show that all recent large tropical volcanic eruptions (1850-present) were followed by surface winter warming in the first Northern Hemisphere (NH) winter after the eruption. Recent studies show that climate models produce a surface winter warming response in the first winter after the largest eruptions, but require a large ensemble of simulations to see significant changes. It is also generally required that the eruption be very large, and only two such eruptions occurred in the historical period: Krakatau in 1883 and Pinatubo in 1991. Here we examine surface winter warming patterns after the 10 largest volcanic eruptions between 850 and 1850 in the Paleoclimate Modeling Intercomparison Project 3 last millennium simulations and in the Community Earth System Model Last Millennium Ensemble. These eruptions were all larger than those since 1850. Though the results depend on both the individual models and the forcing data set used, we have found that models produce a surface winter warming signal in the first winter after large volcanic eruptions, with higher temperatures over NH continents and a stronger polar vortex in the lower stratosphere. We also examined NH summer precipitation responses in the first year after the eruptions, and find clear reductions of summer Asian and African monsoon rainfall.
- Published
- 2017
22. The G4Foam Experiment: global climate impacts of regional ocean albedo modification
- Author
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Alan Robock, Brian Zambri, C. J. Gabriel, Lili Xia, and Ben Kravitz
- Subjects
Atmospheric Science ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,0208 environmental biotechnology ,Global warming ,02 engineering and technology ,Radiative forcing ,Albedo ,01 natural sciences ,lcsh:QC1-999 ,020801 environmental engineering ,lcsh:Chemistry ,lcsh:QD1-999 ,Ocean gyre ,Climatology ,Environmental science ,Climate model ,Precipitation ,Shortwave radiation ,Hadley cell ,lcsh:Physics ,0105 earth and related environmental sciences - Abstract
Reducing insolation has been proposed as a geoengineering response to global warming. Here we present the results of climate model simulations of a unique Geoengineering Model Intercomparison Project Testbed experiment to investigate the benefits and risks of a scheme that would brighten certain oceanic regions. The National Center for Atmospheric Research CESM CAM4-Chem global climate model was modified to simulate a scheme in which the albedo of the ocean surface is increased over the subtropical ocean gyres in the Southern Hemisphere. In theory, this could be accomplished using a stable, nondispersive foam, comprised of tiny, highly reflective microbubbles. Such a foam has been developed under idealized conditions, although deployment at a large scale is presently infeasible. We conducted three ensemble members of a simulation (G4Foam) from 2020 through to 2069 in which the albedo of the ocean surface is set to 0.15 (an increase of 150 %) over the three subtropical ocean gyres in the Southern Hemisphere, against a background of the RCP6.0 (representative concentration pathway resulting in +6 W m−2 radiative forcing by 2100) scenario. After 2069, geoengineering is ceased, and the simulation is run for an additional 20 years. Global mean surface temperature in G4Foam is 0.6 K lower than RCP6.0, with statistically significant cooling relative to RCP6.0 south of 30° N. There is an increase in rainfall over land, most pronouncedly in the tropics during the June–July–August season, relative to both G4SSA (specified stratospheric aerosols) and RCP6.0. Heavily populated and highly cultivated regions throughout the tropics, including the Sahel, southern Asia, the Maritime Continent, Central America, and much of the Amazon experience a statistically significant increase in precipitation minus evaporation. The temperature response to the relatively modest global average forcing of −1.5 W m−2 is amplified through a series of positive cloud feedbacks, in which more shortwave radiation is reflected. The precipitation response is primarily the result of the intensification of the southern Hadley cell, as its mean position migrates northward and away from the Equator in response to the asymmetric cooling.
- Published
- 2017
23. Rapidly expanding nuclear arsenals in Pakistan and India portend regional and global catastrophe
- Author
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Alan Robock, Matthew G. McKinzie, Nicole S. Lovenduski, Charles G. Bardeen, Roy J. Peterson, Lili Xia, Hans M. Kristensen, Cheryl S. Harrison, Richard P. Turco, and Owen B. Toon
- Subjects
Atmospheric Science ,010504 meteorology & atmospheric sciences ,Collateral ,Yield (finance) ,0211 other engineering and technologies ,02 engineering and technology ,macromolecular substances ,Nuclear weapon ,01 natural sciences ,7. Clean energy ,Environmental protection ,skin and connective tissue diseases ,Stratosphere ,Research Articles ,0105 earth and related environmental sciences ,Smoke ,021110 strategic, defence & security studies ,Multidisciplinary ,Primary production ,SciAdv r-articles ,Starvation (glaciology) ,humanities ,13. Climate action ,Environmental science ,sense organs ,Research Article - Abstract
Severe global climate change and a record death toll could result from nuclear war between India and Pakistan in the next decade., Pakistan and India may have 400 to 500 nuclear weapons by 2025 with yields from tested 12- to 45-kt values to a few hundred kilotons. If India uses 100 strategic weapons to attack urban centers and Pakistan uses 150, fatalities could reach 50 to 125 million people, and nuclear-ignited fires could release 16 to 36 Tg of black carbon in smoke, depending on yield. The smoke will rise into the upper troposphere, be self-lofted into the stratosphere, and spread globally within weeks. Surface sunlight will decline by 20 to 35%, cooling the global surface by 2° to 5°C and reducing precipitation by 15 to 30%, with larger regional impacts. Recovery takes more than 10 years. Net primary productivity declines 15 to 30% on land and 5 to 15% in oceans threatening mass starvation and additional worldwide collateral fatalities.
- Published
- 2019
24. 100 Years of progress in understanding the stratosphere and mesosphere
- Author
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Marvin A. Geller, Rolando R. Garcia, Alan Robock, Michaela I. Hegglin, John P. Burrows, Nili Harnik, Neal Butchart, Mark P. Baldwin, Adam A. Scaife, Lesley J. Gray, Thomas Birner, Kevin Hamilton, Guy Brasseur, Ulrike Langematz, and Kaoru Sato
- Subjects
Atmospheric Science ,010504 meteorology & atmospheric sciences ,Potential vorticity ,Atmospheric circulation ,Environmental science ,010502 geochemistry & geophysics ,Oceanography ,Atmospheric sciences ,01 natural sciences ,Stratosphere ,0105 earth and related environmental sciences ,Mesosphere - Abstract
The stratosphere contains ~17% of Earth’s atmospheric mass, but its existence was unknown until 1902. In the following decades our knowledge grew gradually as more observations of the stratosphere were made. In 1913 the ozone layer, which protects life from harmful ultraviolet radiation, was discovered. From ozone and water vapor observations, a first basic idea of a stratospheric general circulation was put forward. Since the 1950s our knowledge of the stratosphere and mesosphere has expanded rapidly, and the importance of this region in the climate system has become clear. With more observations, several new stratospheric phenomena have been discovered: the quasi-biennial oscillation, sudden stratospheric warmings, the Southern Hemisphere ozone hole, and surface weather impacts of stratospheric variability. None of these phenomena were anticipated by theory. Advances in theory have more often than not been prompted by unexplained phenomena seen in new stratospheric observations. From the 1960s onward, the importance of dynamical processes and the coupled stratosphere–troposphere circulation was realized. Since approximately 2000, better representations of the stratosphere—and even the mesosphere—have been included in climate and weather forecasting models. We now know that in order to produce accurate seasonal weather forecasts, and to predict long-term changes in climate and the future evolution of the ozone layer, models with a well-resolved stratosphere with realistic dynamics and chemistry are necessary.
- Published
- 2019
25. Stratospheric sulfate geoengineering could enhance the terrestrial photosynthesis rate
- Author
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Alan Robock, Simone Tilmes, Ryan R. Neely, and Lili Xia
- Subjects
Atmospheric Science ,010504 meteorology & atmospheric sciences ,0208 environmental biotechnology ,chemistry.chemical_element ,02 engineering and technology ,Atmospheric model ,Atmospheric sciences ,7. Clean energy ,01 natural sciences ,Carbon cycle ,Soil respiration ,lcsh:Chemistry ,chemistry.chemical_compound ,Sulfate ,0105 earth and related environmental sciences ,Carbon sink ,15. Life on land ,Radiative forcing ,lcsh:QC1-999 ,020801 environmental engineering ,chemistry ,lcsh:QD1-999 ,13. Climate action ,Climatology ,Environmental science ,Climate model ,Carbon ,lcsh:Physics - Abstract
Stratospheric sulfate geoengineering could impact the terrestrial carbon cycle by enhancing the carbon sink. With an 8 Tg yr−1 injection of SO2 to produce a stratospheric aerosol cloud to balance anthropogenic radiative forcing from the Representative Concentration Pathway 6.0 (RCP6.0) scenario, we conducted climate model simulations with the Community Earth System Model – the Community Atmospheric Model 4 fully coupled to tropospheric and stratospheric chemistry (CAM4–chem). During the geoengineering period, as compared to RCP6.0, land-averaged downward visible (300–700 nm) diffuse radiation increased 3.2 W m−2 (11 %). The enhanced diffuse radiation combined with the cooling increased plant photosynthesis by 0.07 ± 0.02 µmol C m−2 s−1, which could contribute to an additional 3.8 ± 1.1 Gt C yr−1 global gross primary productivity without explicit nutrient limitation. This increase could potentially increase the land carbon sink. Suppressed plant and soil respiration due to the cooling would reduce natural land carbon emission and therefore further enhance the terrestrial carbon sink during the geoengineering period. This potentially beneficial impact of stratospheric sulfate geoengineering would need to be balanced by a large number of potential risks in any future decisions about the implementation of geoengineering.
- Published
- 2016
26. Did Smoke From City Fires in World War II Cause Global Cooling?
- Author
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Alan Robock and Brian Zambri
- Subjects
Smoke ,Atmospheric Science ,010504 meteorology & atmospheric sciences ,0208 environmental biotechnology ,World War II ,02 engineering and technology ,01 natural sciences ,020801 environmental engineering ,Geophysics ,Nuclear winter ,Economy ,Space and Planetary Science ,Earth and Planetary Sciences (miscellaneous) ,Environmental science ,Global cooling ,0105 earth and related environmental sciences - Published
- 2018
27. Stratospheric geoengineering impacts on El Niño/Southern Oscillation
- Author
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Alan Robock and C. J. Gabriel
- Subjects
Atmospheric Science ,010504 meteorology & atmospheric sciences ,business.industry ,Global warming ,Radiative forcing ,010502 geochemistry & geophysics ,Atmospheric sciences ,01 natural sciences ,lcsh:QC1-999 ,lcsh:Chemistry ,Atmosphere ,Amplitude ,El Niño Southern Oscillation ,lcsh:QD1-999 ,13. Climate action ,Climatology ,Co2 concentration ,Environmental science ,Climate model ,Geoengineering ,business ,lcsh:Physics ,0105 earth and related environmental sciences - Abstract
To examine the impact of proposed stratospheric geoengineering schemes on the amplitude and frequency of El Niño/Southern Oscillation (ENSO) variations we examine climate model simulations from the Geoengineering Model Intercomparison Project (GeoMIP) G1–G4 experiments. Here we compare tropical Pacific behavior under anthropogenic global warming (AGW) using several scenarios: an instantaneous quadrupling of the atmosphere's CO2 concentration, a 1 % annual increase in CO2 concentration, and the representative concentration pathway resulting in 4.5 W m−2 radiative forcing at the end of the 21st century, the Representative Concentration Pathway 4.5 scenario, with that under G1–G4 and under historical model simulations. Climate models under AGW project relatively uniform warming across the tropical Pacific over the next several decades. We find no statistically significant change in ENSO frequency or amplitude under stratospheric geoengineering as compared with those that would occur under ongoing AGW, although the relative brevity of the G1–G4 simulations may have limited detectability of such changes. We also find that the amplitude and frequency of ENSO events do not vary significantly under either AGW scenarios or G1–G4 from the variability found within historical simulations or observations going back to the mid-19th century. Finally, while warming of the Niño3.4 region in the tropical Pacific is fully offset in G1 and G2 during the 40-year simulations, the region continues to warm significantly in G3 and G4, which both start from a present-day climate.
- Published
- 2015
28. Modelled and observed sea surface temperature trends for the Caribbean and Antilles
- Author
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Juan Carlos Antuña-Marrero, Michel D. S. Mesquita, Alan Robock, and Odd Helge Otterå
- Subjects
Atmospheric Science ,Coupled model intercomparison project ,Series (stratigraphy) ,010504 meteorology & atmospheric sciences ,0208 environmental biotechnology ,02 engineering and technology ,01 natural sciences ,Climate index ,020801 environmental engineering ,Sea surface temperature ,General Circulation Model ,Climatology ,Atlantic multidecadal oscillation ,Environmental science ,Earth system model ,Climate model ,0105 earth and related environmental sciences - Abstract
The ocean occupies 95% of the Caribbean's area and plays a leading role in the region's climate, thus making the sea surface temperature (SST) a very important regional climate index. This, in conjunction with the lack of a regionally consistent, quality-controlled surface temperature dataset increases the scientific value of using SST to characterize the regional climate and its trends. This study determines the magnitudes of the long-term SST trends in the Wider Caribbean (WC) and the Antilles. We overcome the presence of discontinuity points in the SST time series using the change point statistical technique. Annual mean SST trends combining the subperiods 1906–1969 and 1972–2005 are 1.32 ± 0.41 °C per century for the Antilles and 1.08 ± 0.32 °C per century for the WC. For the same regions during the subperiod 1972–2005, the corresponding trends are 1.41 ± 0.68 °C per century and 1.18 ± 0.49 °C per century, illustrating the warming intensification during the last four decades. A significant correlation is found between the SSTs in the Caribbean and Atlantic Multidecadal Oscillation (AMO) index, suggesting a potential link between Caribbean SSTs and the mechanisms governing the Atlantic basin-wide SSTs. Finally, the capabilities of two state-of-the-art coupled climate models, the Norwegian Earth System Model (NorESM1-M) and the Bergen Climate Model (BCM), to simulate SST in the Caribbean were tested. Both models produce an adequate simulation of the annual mean SST anomalies and SST seasonal cycle for the WC and the Antilles. The simulated annual and monthly mean SSTs are colder in the two models compared to the observations, a common feature among the majority of general circulation models participating in the Coupled Model Intercomparison Project Phase 5. However, despite these minor deficiencies both BCM and NorESM1-M are considered adequate for conducting SST simulations relevant for future climate change research in the Caribbean.
- Published
- 2015
29. Cooperation on GPS Meteorology between the United States and Cuba
- Author
-
Juan Carlos Antuña-Marrero, René Estevan Arredondo, Richard A. Anthes, John Braun, Alan Robock, and Oswaldo Garcia
- Subjects
Atmospheric Science ,GPS meteorology ,Atmospheric water ,History ,Meteorology ,business.industry ,Global Positioning System ,Gps receiver ,Library science ,business ,Atmospheric research ,North Atlantic Treaty ,Highly sensitive - Abstract
In May 2014 a team of atmospheric and geodetic scientists from UNAVCO and the University Corporation for Atmospheric Research (UCAR) sent and helped set up a global positioning system (GPS) receiver to measure atmospheric water vapor at the Grupo de Óptica Atmosférica de Camagüey (GOAC) at the Camagüey Meteorological Center in Camagüey, Cuba. The GPS receiver immediately began to produce observations of precipitable water, which are being shared with the international meteorological community. Obtaining permission from both sides to send a highly sensitive instrument from the United States to Cuba was not easy. This paper describes the series of events that led to this achievement, beginning with a North Atlantic Treaty Organization (NATO) workshop in Rome, Italy, in 1994 in which Alan Robock met a young Cuban scientist named Juan Carlos Antuña and accepted him as a graduate student at the University of Maryland, College Park. The GPS meteorology connection began with a March 2007 visit of a delegation from the United States headed by then American Meteorological Society (AMS) President Richard Anthes to Havana, Cuba, at the invitation of the Cuban Meteorological Society president, Andrés Planas. These two threads led to this remarkable cooperation between Cuban and U.S. scientists. Several visits to Cuba beginning in 2010 by Robock, who met former President of Cuba Fidel Castro and the science advisor to the president of Cuba, played a significant role. This is another instance (the visit of the AMS delegation to China in 1974 was a prime example) of how communication and visits between meteorologists in countries that are at odds on many other issues can lead to lasting collaborations that benefit both countries as well as the international community.
- Published
- 2015
30. Impacts of stratospheric sulfate geoengineering on tropospheric ozone
- Author
-
Alan Robock, Peer Nowack, Simone Tilmes, Lili Xia, and Apollo - University of Cambridge Repository
- Subjects
Atmospheric Science ,Ozone ,010504 meteorology & atmospheric sciences ,010501 environmental sciences ,Solar irradiance ,Atmospheric sciences ,Global dimming ,01 natural sciences ,lcsh:Chemistry ,chemistry.chemical_compound ,Solar radiation management ,Ozone layer ,Meteorology & Atmospheric Sciences ,Tropospheric ozone ,0105 earth and related environmental sciences ,13 Climate Action ,Global warming ,37 Earth Sciences ,Ozone depletion ,lcsh:QC1-999 ,lcsh:QD1-999 ,chemistry ,Climatology ,3701 Atmospheric Sciences ,Environmental science ,lcsh:Physics - Abstract
A range of solar radiation management (SRM) techniques has been proposed to counter anthropogenic climate change. Here, we examine the potential effects of stratospheric sulfate aerosols and solar insolation reduction on tropospheric ozone and ozone at Earth's surface. Ozone is a key air pollutant, which can produce respiratory diseases and crop damage. Using a version of the Community Earth System Model from the National Center for Atmospheric Research that includes comprehensive tropospheric and stratospheric chemistry, we model both stratospheric sulfur injection and solar irradiance reduction schemes, with the aim of achieving equal levels of surface cooling relative to the Representative Concentration Pathway 6.0 scenario. This allows us to compare the impacts of sulfate aerosols and solar dimming on atmospheric ozone concentrations. Despite nearly identical global mean surface temperatures for the two SRM approaches, solar insolation reduction increases global average surface ozone concentrations, while sulfate injection decreases it. A fundamental difference between the two geoengineering schemes is the importance of heterogeneous reactions in the photochemical ozone balance with larger stratospheric sulfate abundance, resulting in increased ozone depletion in mid- and high latitudes. This reduces the net transport of stratospheric ozone into the troposphere and thus is a key driver of the overall decrease in surface ozone. At the same time, the change in stratospheric ozone alters the tropospheric photochemical environment due to enhanced ultraviolet radiation. A shared factor among both SRM scenarios is decreased chemical ozone loss due to reduced tropospheric humidity. Under insolation reduction, this is the dominant factor giving rise to the global surface ozone increase. Regionally, both surface ozone increases and decreases are found for both scenarios; that is, SRM would affect regions of the world differently in terms of air pollution. In conclusion, surface ozone and tropospheric chemistry would likely be affected by SRM, but the overall effect is strongly dependent on the SRM scheme. Due to the health and economic impacts of surface ozone, all these impacts should be taken into account in evaluations of possible consequences of SRM.
- Published
- 2017
31. LALINET: The First Latin American–Born Regional Atmospheric Observational Network
- Author
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Juan Luis Guerrero-Rascado, Alvaro Bastidas, Elena Montilla-Rosero, Angel Máximo de Frutos Baraja, Juan Carlos Antuña-Marrero, Pablo Ristori, Eduardo Landulfo, Ricardo Forno, Barclay Clemesha, David N. Whiteman, Alan Robock, Fábio Lopes, Henrique M. J. Barbosa, Boris Barja, Francesco Zaratti, Eduardo Quel, Elian Wolfram, René Estevan, and Errico Armandillo
- Subjects
Atmospheric Science ,Enthusiasm ,Latin Americans ,010504 meteorology & atmospheric sciences ,Meteorology ,media_common.quotation_subject ,LALINET ,01 natural sciences ,Ciencias de la Tierra y relacionadas con el Medio Ambiente ,010309 optics ,purl.org/becyt/ford/1 [https] ,purl.org/becyt/ford/1.5 [https] ,Lidar ,Political science ,0103 physical sciences ,Regional science ,Observational study ,Meteorología y Ciencias Atmosféricas ,lidar ,CIENCIAS NATURALES Y EXACTAS ,0105 earth and related environmental sciences ,media_common - Abstract
Sustained and coordinated efforts of lidar teams in Latin America at the beginning of the 21st century have built LALINET (Latin American Lidar NETwork), the only observational network in Latin America created by the agreement and commitment of Latin American scientists. They worked with limited funding but an abundance of enthusiasm and commitment toward their joint goal. Before LALINET, there were a few pioneering lidar stations operating in Latin America, described briefly here. Bi-annual Latin American Lidar Workshops, held from 2001 to the present, supported both the development of the regional lidar community and LALINET. At those meetings, lidar researchers from Latin America meet to conduct regular scientific and technical exchanges among themselves and with experts from the rest of the world. Regional and international scientific cooperation has played an important role for the development of both the individual teams and the network. The current LALINET status and activities are described, emphasizing the processes of standardization of the measurements, methodologies, calibration protocols, and retrieval algorithms. Failures and successes achieved in the buildup of LALINET are presented. In addition, the first LALINET joint measurement campaign and a set of aerosol extinction profile measurements obtained from the aerosol plume produced by the Calbuco volcano eruption on April 22, 2015, are described and discussed. Fil: Antuña Marrero, Juan Carlos. Centro Meteorológico de Camagüey; Cuba Fil: Landulfo, Eduardo. Instituto de Pesquisas Energéticas e Nucleares; Brasil Fil: Estevan, René. Centro Meteorológico de Camagüey; Cuba Fil: Barja, Boris. Centro Meteorológico de Camagüey; Cuba. Universidade de Sao Paulo; Brasil Fil: Robock, Alan. State University of New Jersey; Estados Unidos Fil: Wolfram, Elian Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; Argentina Fil: Ristori, Pablo Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; Argentina Fil: Clemesha, Barclay. Upper Atmosphere Research Group; Brasil Fil: Zaratti, Francesco. Universidad Mayor de San Andrés; Bolivia Fil: Forno, Ricardo. Universidad Mayor de San Andrés; Bolivia Fil: Armandillo, Errico. ESTEC; Países Bajos Fil: Bastidas, Álvaro E.. Universidad Nacional de Colombia. Sede Medellin; Colombia Fil: de Frutos Baraja, Ángel Máximo. Universidad de Valladolid; España Fil: Whiteman, David N.. National Aeronautics and Space Administration; Estados Unidos Fil: Quel, Eduardo Jaime. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; Argentina Fil: Barbosa, Henrique M. J.. Universidade de Sao Paulo; Brasil Fil: Lopes, Fabio. Comissao Nacional de Energia Nuclear. Centro de Lasers e Aplicacoes. Instituto de Pesquisas Energeticas e Nucleares.; Brasil Fil: Montilla-Rosero, Elena. Universidad de Concepción; Chile. Universidad Escuela de Administración, Finanzas e Instituto Tecnológico; Colombia Fil: Guerrero Rascado, Juan L.. Comissao Nacional de Energia Nuclear. Centro de Lasers e Aplicacoes. Instituto de Pesquisas Energeticas e Nucleares.; Brasil. Universidad de Granada; España
- Published
- 2017
32. Influences of soil moisture and vegetation on convective precipitation forecasts over the United States Great Plains
- Author
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Alan Robock, Wei Wu, and Thomas W. Collow
- Subjects
Atmospheric Science ,Humidity ,Vegetation ,Moisture advection ,Convective available potential energy ,Geophysics ,Space and Planetary Science ,Climatology ,Weather Research and Forecasting Model ,Earth and Planetary Sciences (miscellaneous) ,Environmental science ,Soil horizon ,Precipitation ,Water content - Abstract
This study investigates the influences of soil moisture and vegetation on 30 h convective precipitation forecasts using the Weather Research and Forecasting model over the United States Great Plains with explicit treatment of convection. North American Regional Reanalysis (NARR) data were used as initial and boundary conditions. We also used an adjusted soil moisture (uniformly adding 0.10 m3/m3 over all soil layers based on NARR biases) to determine whether using a simple observationally based adjustment of soil moisture forcing would provide more accurate simulations and how the soil moisture addition would impact meteorological parameters for different vegetation types. Current and extreme (forest and barren) land covers were examined. Compared to the current vegetation cover, the complete removal of vegetation produced substantially less precipitation, while conversion to forest led to small differences in precipitation. Adding 0.10 m3/m3 to the soil moisture with the current vegetation cover lowered the near surface temperature and increased the humidity to a similar degree as using a fully forested domain with no soil moisture adjustment. However, these temperature and humidity effects on convective available potential energy and moist enthalpy nearly canceled each other out, resulting in a limited precipitation response. Although no substantial changes in precipitation forecasts were found using the adjusted soil moisture, the similarity found between temperature and humidity forecasts using the increased soil moisture and those with a forested domain highlights the sensitivity of the model to soil moisture changes, reinforcing the need for accurate soil moisture initialization in numerical weather forecasting models.
- Published
- 2014
33. Solar radiation management impacts on agriculture in China: A case study in the Geoengineering Model Intercomparison Project (GeoMIP)
- Author
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Jin-Ho Yoon, Charles L. Curry, Andrew Jones, Simone Tilmes, Ben Kravitz, Ulrike Niemeier, Jason N. S. Cole, Helene Muri, John C. Moore, Duoying Ji, Lili Xia, Balwinder Singh, Shingo Watanabe, and Alan Robock
- Subjects
2. Zero hunger ,Atmospheric Science ,business.industry ,Climate change ,15. Life on land ,Radiative forcing ,7. Clean energy ,Geophysics ,13. Climate action ,Space and Planetary Science ,Agriculture ,Solar radiation management ,Climatology ,Earth and Planetary Sciences (miscellaneous) ,Environmental science ,DSSAT ,Climate model ,Precipitation ,Agricultural productivity ,business - Abstract
Geoengineering via solar radiation management could affect agricultural productivity due to changes in temperature, precipitation, and solar radiation. To study rice and maize production changes in China, we used results from 10 climate models participating in the Geoengineering Model Intercomparison Project (GeoMIP) G2 scenario to force the Decision Support System for Agrotechnology Transfer (DSSAT) crop model. G2 prescribes an insolation reduction to balance a 1% a(-1) increase in CO2 concentration (1pctCO2) for 50 years. We first evaluated the DSSAT model using 30 years (1978-2007) of daily observed weather records and agriculture practices for 25 major agriculture provinces in China and compared the results to observations of yield. We then created three sets of climate forcing for 42 locations in China for DSSAT from each climate model experiment: (1) 1pctCO2, (2) G2, and (3) G2 with constant CO2 concentration (409 ppm) and compared the resulting agricultural responses. In the DSSAT simulations: (1) Without changing management practices, the combined effect of simulated climate changes due to geoengineering and CO2 fertilization during the last 15 years of solar reduction would change rice production in China by 3.0 +/- 4.0 megaton (Mt) (2.4 +/- 4.0%) as compared with 1pctCO2 and increase Chinese maize production by 18.1 +/- 6.0 Mt (13.9 +/- 5.9%). (2) The termination of geoengineering shows negligible impacts on rice production but a 19.6 Mt (11.9%) reduction of maize production as compared to the last 15 years of geoengineering. (3) The CO2 fertilization effect compensates for the deleterious impacts of changes in temperature, precipitation, and solar radiation due to geoengineering on rice production, increasing rice production by 8.6 Mt. The elevated CO2 concentration enhances maize production in G2, contributing 7.7 Mt (42.4%) to the total increase. Using the DSSAT crop model, virtually all of the climate models agree on the sign of the responses, even though the spread across models is large. This suggests that solar radiation management would have little impact on rice production in China but could increase maize production.
- Published
- 2014
34. Forcings and feedbacks in the GeoMIP ensemble for a reduction in solar irradiance and increase in CO2
- Author
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Nicolás Huneeus, Kari Alterskjær, Jón Egill Kristjánsson, Ben Kravitz, Ulrike Niemeier, Jin-Ho Yoon, Helene Muri, Phil Rasch, Jason N. S. Cole, Simone Tilmes, Andrew Jones, Charles L. Curry, Michael Schulz, Duoying Ji, Olivier Boucher, John C. Moore, Alan Robock, Hauke Schmidt, Balwinder Singh, and Shingo Watanabe
- Subjects
Cloud forcing ,Atmospheric Science ,Solar constant ,010504 meteorology & atmospheric sciences ,Forcing (mathematics) ,Radiative forcing ,010502 geochemistry & geophysics ,Atmospheric sciences ,Solar irradiance ,01 natural sciences ,Cloud feedback ,Geophysics ,13. Climate action ,Space and Planetary Science ,Climatology ,Earth and Planetary Sciences (miscellaneous) ,Climate sensitivity ,Environmental science ,Shortwave ,0105 earth and related environmental sciences - Abstract
The effective radiative forcings (including rapid adjustments) and feedbacks associated with an instantaneous quadrupling of the preindustrial CO2 concentration and a counterbalancing reduction of the solar constant are investigated in the context of the Geoengineering Model Intercomparison Project (GeoMIP). The forcing and feedback parameters of the net energy flux, as well as its different components at the top-of-atmosphere (TOA) and surface, were examined in 10 Earth System Models to better understand the impact of solar radiation management on the energy budget. In spite of their very different nature, the feedback parameter and its components at the TOA and surface are almost identical for the two forcing mechanisms, not only in the global mean but also in their geographical distributions. This conclusion holds for each of the individual models despite intermodel differences in how feedbacks affect the energy budget. This indicates that the climate sensitivity parameter is independent of the forcing (when measured as an effective radiative forcing). We also show the existence of a large contribution of the cloudy-sky component to the shortwave effective radiative forcing at the TOA suggesting rapid cloud adjustments to a change in solar irradiance. In addition, the models present significant diversity in the spatial distribution of the shortwave feedback parameter in cloudy regions, indicating persistent uncertainties in cloud feedback mechanisms.
- Published
- 2014
35. Stratospheric ozone response to sulfate geoengineering: Results from the Geoengineering Model Intercomparison Project (GeoMIP)
- Author
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Eva Mancini, Alan Robock, Valentina Aquila, Simone Tilmes, Glauco Di Genova, Giovanni Pitari, Natalia De Luca, Irene Cionni, Ben Kravitz, and Shingo Watanabe
- Subjects
Atmospheric Science ,Ozone ,Dobson unit ,Radiative forcing ,Atmospheric sciences ,Ozone depletion ,chemistry.chemical_compound ,Geophysics ,chemistry ,Space and Planetary Science ,Climatology ,Ozone layer ,Earth and Planetary Sciences (miscellaneous) ,Environmental science ,Sulfate aerosol ,Tropopause ,Sulfate - Abstract
Geoengineering with stratospheric sulfate aerosols has been proposed as a means of temporarily cooling the planet, alleviating some of the side effects of anthropogenic CO2 emissions. However, one of the known side effects of stratospheric injections of sulfate aerosols under present-day conditions is a general decrease in ozone concentrations. Here we present the results from two general circulation models and two coupled chemistry-climate models within the experiments G3 and G4 of the Geoengineering Model Intercomparison Project. On average, the models simulate in G4 an increase in sulfate aerosol surface area density similar to conditions a year after the Mount Pinatubo eruption and a decrease in globally averaged ozone by 1.1−2.1 DU (Dobson unit, 1 DU = 0.001 atm cm) during the central decade of the experiment (2040–2049). Enhanced heterogeneous chemistry on sulfate aerosols leads to an ozone increase in low and middle latitudes, whereas enhanced heterogeneous reactions in polar regions and increased tropical upwelling lead to a reduction of stratospheric ozone. The increase in UV-B radiation at the surface due to ozone depletion is offset by the screening due to the aerosols in the tropics and midlatitudes, while in polar regions the UV-B radiation is increased by 5% on average, with 12% peak increases during springtime. The contribution of ozone changes to the tropopause radiative forcing during 2040–2049 is found to be less than −0.1 W m−2. After 2050, because of decreasing ClOx concentrations, the suppression of the NOx cycle becomes more important than destruction of ozone by ClOx, causing an increase in total stratospheric ozone.
- Published
- 2014
36. Arctic cryosphere response in the Geoengineering Model Intercomparison Project G3 and G4 scenarios
- Author
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Andrew Jones, Mira Berdahl, John C. Moore, Duoying Ji, Alan Robock, Shingo Watanabe, and Ben Kravitz
- Subjects
Arctic sea ice decline ,Atmospheric Science ,geography ,geography.geographical_feature_category ,Radiative forcing ,Snow ,Atmospheric sciences ,Arctic ice pack ,Arctic geoengineering ,chemistry.chemical_compound ,Geophysics ,chemistry ,Space and Planetary Science ,Climatology ,Earth and Planetary Sciences (miscellaneous) ,Sea ice ,Cryosphere ,Environmental science ,Sulfate aerosol - Abstract
We analyzed output from the Geoengineering Model Intercomparison Project for the two most “realistic” scenarios, which use the representative concentration pathway of 4.5 Wm−2 by 2100 (RCP4.5) as the control run and inject sulfate aerosol precursors into the stratosphere. The first experiment, G3, is specified to keep RCP4.5 top of atmosphere net radiation at 2020 values by injection of sulfate aerosols, and the second, G4, injects 5 Tg SO2 per year. We ask whether geoengineering by injection of sulfate aerosols into the lower stratosphere from the years 2020 to 2070 is able to prevent the demise of Northern Hemispere minimum annual sea ice extent or slow spring Northern Hemispere snow cover loss. We show that in all available models, despite geoengineering efforts, September sea ice extents still decrease from 2020 to 2070, although not as quickly as in RCP4.5. In two of five models, total September ice loss occurs before 2060. Spring snow extent is increased from 2020 to 2070 compared to RCP4.5 although there is still a negative trend in 3 of 4 models. Because of the climate system lag in responding to the existing radiative forcing, to stop Arctic sea ice and snow from continuing to melt, the imposed forcing would have to be large enough to also counteract the existing radiative imbalance. After the cessation of sulfate aerosol injection in 2070, the climate system rebounds to the warmer RCP4.5 state quickly, and thus, any sea ice or snow retention as a result of geoengineering is lost within a decade.
- Published
- 2014
37. The impact of abrupt suspension of solar radiation management (termination effect) in experiment G2 of the Geoengineering Model Intercomparison Project (GeoMIP)
- Author
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Jón Egill Kristjánsson, Ben Kravitz, Ulrike Niemeier, Olivier Boucher, Jason N. S. Cole, Alan Robock, Charles L. Curry, Peter J. Irvine, Duoying Ji, Andrew Jones, Simone Tilmes, Jim Haywood, Jin-Ho Yoon, John C. Moore, Kari Alterskjær, Balwinder Singh, Shingo Watanabe, and Hauke Schmidt
- Subjects
Atmospheric Science ,010504 meteorology & atmospheric sciences ,Primary production ,Climate change ,010501 environmental sciences ,15. Life on land ,Atmospheric sciences ,01 natural sciences ,Latitude ,Degree (temperature) ,Geophysics ,Arctic ,13. Climate action ,Space and Planetary Science ,Solar radiation management ,Climatology ,Earth and Planetary Sciences (miscellaneous) ,Environmental science ,Climate model ,Precipitation ,0105 earth and related environmental sciences - Abstract
[1] We have examined changes in climate which result from the sudden termination of geoengineering after 50 years of offsetting a 1% per annum increase in CO2 concentrations by a reduction of solar radiation, as simulated by 11 different climate models in experiment G2 of the Geoengineering Model Intercomparison Project. The models agree on a rapid increase in global-mean temperature following termination accompanied by increases in global-mean precipitation rate and decreases in sea-ice cover. There is no agreement on the impact of geoengineering termination on the rate of change of global-mean plant net primary productivity. There is a considerable degree of consensus for the geographical distribution of temperature change following termination, with faster warming at high latitudes and over land. There is also considerable agreement regarding the distribution of reductions in Arctic sea-ice, but less so for the Antarctic. There is much less agreement regarding the patterns of change in precipitation and net primary productivity, with a greater degree of consensus at higher latitudes.
- Published
- 2013
38. Climate model response from the Geoengineering Model Intercomparison Project (GeoMIP)
- Author
-
Hauke Schmidt, Jason N. S. Cole, Alan Robock, Jim Haywood, Duoying Ji, Peter J. Irvine, Michael Schulz, Simone Tilmes, Diana Bou Karam, Philip J. Rasch, Shuting Yang, Ken Caldeira, John C. Moore, Olivier Boucher, Andrew Jones, Jón Egill Kristjánsson, Kari Alterskjær, Ben Kravitz, Ulrike Niemeier, Jin-Ho Yoon, Balwinder Singh, Shingo Watanabe, Charles L. Curry, and Daniel J. Lunt
- Subjects
Earth's energy budget ,Atmospheric Science ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Global temperature ,010501 environmental sciences ,15. Life on land ,Atmospheric sciences ,01 natural sciences ,Geophysics ,13. Climate action ,Space and Planetary Science ,Solar radiation management ,Climatology ,Greenhouse gas ,Earth and Planetary Sciences (miscellaneous) ,Sea ice ,Environmental science ,Climate model ,Precipitation ,Water cycle ,0105 earth and related environmental sciences - Abstract
Solar geoengineering - deliberate reduction in the amount of solar radiation retained by the Earth - has been proposed as a means of counteracting some of the climatic effects of anthropogenic greenhouse gas emissions. We present results from Experiment G1 of the Geoengineering Model Intercomparison Project, in which 12 climate models have simulated the climate response to an abrupt quadrupling of CO2 from preindustrial concentrations brought into radiative balance via a globally uniform reduction in insolation. Models show this reduction largely offsets global mean surface temperature increases due to quadrupled CO2 concentrations and prevents 97% of the Arctic sea ice loss that would otherwise occur under high CO2 levels but, compared to the preindustrial climate, leaves the tropics cooler (-0.3 K) and the poles warmer (+0.8 K). Annual mean precipitation minus evaporation anomalies for G1 are less than 0.2 mm day-1 in magnitude over 92% of the globe, but some tropical regions receive less precipitation, in part due to increased moist static stability and suppression of convection. Global average net primary productivity increases by 120% in G1 over simulated preindustrial levels, primarily from CO2 fertilization, but also in part due to reduced plant heat stress compared to a high CO2 world with no geoengineering. All models show that uniform solar geoengineering in G1 cannot simultaneously return regional and global temperature and hydrologic cycle intensity to preindustrial levels. Key Points Temperature reduction from uniform geoengineering is not uniform Geoengineering cannot offset both temperature and hydrology changes NPP increases mostly due to CO2 fertilization ©2013. American Geophysical Union. All Rights Reserved.
- Published
- 2013
39. Baffin Island snow extent sensitivity: Insights from a regional climate model
- Author
-
Alan Robock and Mira Berdahl
- Subjects
Arctic sea ice decline ,Atmospheric Science ,geography ,geography.geographical_feature_category ,Snow field ,Snow ,Arctic ice pack ,Geophysics ,Space and Planetary Science ,Climatology ,Earth and Planetary Sciences (miscellaneous) ,Sea ice ,Snow line ,Cryosphere ,Ice sheet ,Geology - Abstract
[1] Recent modeling efforts suggest that the Little Ice Age (LIA) onset could be explained by a series of four large decadally-spaced volcanic eruptions. At that time, glaciers on Baffin Island advanced and did not retreat until the past century, perhaps due to Arctic and North Atlantic Ocean sea ice feedbacks. To try to determine what parameters sustain snow cover, we investigate the relative impacts of changes in radiation and advection on minimum summer snow extent over Baffin Island. We used the Weather Research and Forecasting (WRF) model to run eight 6 month long (April-September), 10 km resolution simulations, in which we varied boundary condition temperatures, solar radiation, and sea ice cover. Although the Control Run underestimated cloud cover and thus produced an exaggerated diurnal 2 m temperature cycle, the relative changes of snow extent show that WRF accurately simulates snow expansion into the same regions as during the LIA. With an average temperature decrease from current temperatures by −3.9 ± 1.1 K, it only requires one season for the model to lower the snowline by comparable elevation changes seen during the descent into the LIA. WRF's maximum snow line sensitivity is 7 K/km, within the range of the typically assumed lapse rate of 5–7 K/km in the Canadian Arctic. Thus, if a shift in the Arctic climate greatly expanded sea ice coverage following large volcanic eruptions, this would have been enough to perpetuate an ice sheet on Baffin Island throughout the LIA.
- Published
- 2013
40. Studying geoengineering with natural and anthropogenic analogs
- Author
-
Douglas G. MacMartin, Matthew Christensen, Riley M. Duren, and Alan Robock
- Subjects
Atmospheric Science ,Global and Planetary Change ,geography ,Vulcanian eruption ,geography.geographical_feature_category ,Meteorology ,Ship tracks ,Radiative forcing ,Volcano ,Solar radiation management ,Cloud albedo ,Environmental science ,Stratosphere ,Volcanic ash - Abstract
Solar radiation management (SRM) has been proposed as a possible option for offsetting some anthropogenic radiative forcing, with the goal of reducing some of the associated climatic changes. There are clearly significant uncertainties associated with SRM, and even small-scale experiments that might reduce uncertainty would carry some risk. However, there are also natural and anthropogenic analogs to SRM, such as volcanic eruptions in the case of stratospheric aerosol injection and ship tracks in the case of marine cloud albedo modification. It is essential to understand what we can learn from these analogs in order to validate models, particularly because of the problematic nature of outdoor experiments. It is also important to understand what we cannot learn, as this might better focus attention on what risks would need to be solely examined by numerical models. Stratospheric conditions following a major volcanic eruption, for example, are not the same as those to be expected from intentional geoengineering, both because of confounding effects of volcanic ash and the differences between continuous and impulsive injection of material into the stratosphere. Nonetheless, better data would help validate models; we thus recommend an appropriate plan be developed to better monitor the next large volcanic eruption. Similarly, more could be learned about cloud albedo modification from careful study not only of ship tracks, but of ship and other aerosol emission sources in cloud regimes beyond the narrow conditions under which ship tracks form; this would benefit from improved satellite observing capabilities.
- Published
- 2013
41. Tambora 1815 as a test case for high impact volcanic eruptions: Earth system effects
- Author
-
Juerg Luterbacher, Hans-F. Graf, Philip Brohan, Stefan Brönnimann, Renate Auchmann, Adjat Sudrajat, Stephen Self, Raphael Neukom, Philip Jones, Martin Wegmann, Claudia Timmreck, Christoph C. Raible, Thomas L. Frölicher, Stefan Muthers, and Alan Robock
- Subjects
Atmospheric Science ,Global and Planetary Change ,Paleoclimate ,010504 meteorology & atmospheric sciences ,530 Physics ,Climate oscillation ,Geography, Planning and Development ,Climate change ,010502 geochemistry & geophysics ,01 natural sciences ,Advanced Review ,13. Climate action ,Polar vortex ,Climatology ,Paleoclimatology ,Advanced Reviews ,Climate model ,Climate state ,910 Geography & travel ,Water cycle ,Global cooling ,550 Earth sciences & geology ,Geology ,0105 earth and related environmental sciences - Abstract
The eruption of Tambora (Indonesia) in April 1815 had substantial effects on global climate and led to the 'Year Without a Summer' of 1816 in Europe and North America. Although a tragic event-tens of thousands of people lost their lives-the eruption also was an 'experiment of nature' from which science has learned until today. The aim of this study is to summarize our current understanding of the Tambora eruption and its effects on climate as expressed in early instrumental observations, climate proxies and geological evidence, climate reconstructions, and model simulations. Progress has been made with respect to our understanding of the eruption process and estimated amount of SO2 injected into the atmosphere, although large uncertainties still exist with respect to altitude and hemispheric distribution of Tambora aerosols. With respect to climate effects, the global and Northern Hemispheric cooling are well constrained by proxies whereas there is no strong signal in Southern Hemisphere proxies. Newly recovered early instrumental information for Western Europe and parts of North America, regions with particularly strong climate effects, allow Tambora's effect on the weather systems to be addressed. Climate models respond to prescribed Tambora-like forcing with a strengthening of the wintertime stratospheric polar vortex, global cooling and a slowdown of the water cycle, weakening of the summer monsoon circulations, a strengthening of the Atlantic Meridional Overturning Circulation, and a decrease of atmospheric CO2. Combining observations, climate proxies, and model simulations for the case of Tambora, a better understanding of climate processes has emerged. WIREs Clim Change 2016, 7:569-589. doi: 10.1002/wcc.407 This article is categorized under: 1Paleoclimates and Current Trends > Paleoclimate.
- Published
- 2016
42. Impacts of a nuclear war in South Asia on soybean and maize production in the Midwest United States
- Author
-
Mutlu Ozdogan, Alan Robock, and Christopher J. Kucharik
- Subjects
Agroecosystem ,Atmospheric Science ,Global and Planetary Change ,South asia ,Yield (finance) ,food and beverages ,Growing season ,Climate change ,Troposphere ,Agronomy ,Climatology ,Environmental science ,Climate model ,Precipitation - Abstract
Crop production would decline in the Midwestern United States from climate change following a regional nuclear conflict between India and Pakistan. Using Agro-IBIS, a dynamic agroecosystem model, we simulated the response of maize and soybeans to cooler, drier, and darker conditions from war-related smoke. We combined observed climate conditions for the states of Iowa, Illinois, Indiana, and Missouri with output from a general circulation climate model simulation that injected 5 Tg of elemental carbon into the upper troposphere. Both maize and soybeans showed notable yield reductions for a decade after the event. Maize yields declined 10–40 % while soybean yields dropped 2–20 %. Temporal variation in magnitude of yield for both crops generally followed the variation in climatic anomalies, with the greatest decline in the 5 years following the 5 Tg event and then less, but still substantial yield decline, for the rest of the decade. Yield reduction for both crops was linked to changes in growing period duration and, less markedly, to reduced precipitation and altered maximum daily temperature during the growing season. The seasonal average of daily maximum temperature anomalies, combined with precipitation and radiation changes, had a quadratic relationship to yield differences; small (0 °C) and large (−3 °C) maximum temperature anomalies combined with other changes led to increased yield loss, but medium changes (−1 °C) had small to neutral effects on yield. The exact timing of the temperature changes during the various crop growth phases also had an important effect.
- Published
- 2012
43. Impacts of a nuclear war in South Asia on rice production in Mainland China
- Author
-
Lili Xia and Alan Robock
- Subjects
Mainland China ,Atmospheric Science ,Global and Planetary Change ,business.industry ,Yield (finance) ,food and beverages ,Climate change ,Agricultural economics ,Geography ,Agriculture ,Climatology ,Period (geology) ,Precipitation ,Agricultural productivity ,China ,business - Abstract
A regional nuclear war between India and Pakistan with a 5 Tg black carbon injection into the upper troposphere would produce significant climate changes for a decade, including cooling, reduction of solar radiation, and reduction of precipitation, which are all important factors controlling agricultural productivity. We used the Decision Support System for Agrotechnology Transfer agricultural simulation model to simulate regional nuclear war impacts on rice yield in 24 provinces in China. We first evaluated the model by forcing it with daily weather data and management practices for the period 1980–2008 for 24 provinces in China, and compared the results to observations of rice yields in China. Then we perturbed observed weather data using climate anomalies for a 10-year period from a nuclear war simulation. We perturbed each year of the 30-year climate record with anomalies from each year of the 10-year nuclear war simulations for different regions in China. We found that rice production would decline by an average of 21 % for the first 4 years after soot injection, and would slowly recover in the following years. For the next 6 years, the reduction in rice production was about 10 %. Different regions responded differently to climate changes from nuclear war. Rice production in northern China was damaged severely, while regions along the south and east coasts showed a positive response to regional nuclear war. Although we might try to adapt to a perturbed climate by enhancing rice planting activity in southern and eastern China or increasing fertilizer usage, both methods have severe limitations. The best solution to avoid nuclear war impacts on agriculture is to avoid nuclear war, and this can only be guaranteed with a nuclear-weapon-free world.
- Published
- 2012
44. The Geoengineering Model Intercomparison Project (GeoMIP)
- Author
-
Ben Kravitz, Olivier Boucher, Alan Robock, Michael Schulz, Karl E. Taylor, Georgiy L. Stenchikov, Hauke Schmidt, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
- Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,Atmospheric Science ,010504 meteorology & atmospheric sciences ,Meteorology ,business.industry ,Global warming ,Climate change ,Forcing (mathematics) ,010501 environmental sciences ,01 natural sciences ,13. Climate action ,Solar radiation management ,Climatology ,Environmental science ,Climate model ,Geoengineering ,Climate engineering ,[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment ,business ,Robustness (economics) ,ComputingMilieux_MISCELLANEOUS ,0105 earth and related environmental sciences - Abstract
To evaluate the effects of stratospheric geoengineering with sulphate aerosols, we propose standard forcing scenarios to be applied to multiple climate models to compare their results and determine the robustness of their responses. Thus far, different modeling groups have used different forcing scenarios for both global warming and geoengineering, complicating the comparison of results. We recommend four experiments to explore the extent to which geoengineering might offset climate change projected in some of the Climate Model Intercomparison Project 5 experiments. These experiments focus on stratospheric aerosols, but future experiments under this framework may focus on different means of geoengineering. Copyright © 2011 Royal Meteorological Society and Crown copyright
- Published
- 2011
45. Geoengineering by stratospheric SO2 injection: results from the Met Office HadGEM2 climate model and comparison with the Goddard Institute for Space Studies ModelE
- Author
-
A. Jones, Jim Haywood, Alan Robock, Ben Kravitz, and Olivier Boucher
- Subjects
Atmospheric Science ,010504 meteorology & atmospheric sciences ,business.industry ,Continuous injection ,0207 environmental engineering ,02 engineering and technology ,010502 geochemistry & geophysics ,Atmospheric sciences ,01 natural sciences ,Geographic distribution ,13. Climate action ,Air temperature ,Climatology ,Environmental science ,Climate model ,Precipitation ,Geoengineering ,020701 environmental engineering ,business ,Stratosphere ,0105 earth and related environmental sciences - Abstract
We examine the response of the Met Office Hadley Centre's HadGEM2-AO climate model to simulated geoengineering by continuous injection of SO2 into the lower stratosphere, and compare the results with those from the Goddard Institute for Space Studies ModelE. The HadGEM2 simulations suggest that the SO2 injection rate considered here (5 Tg[SO2] yr−1) could defer the amount of global warming predicted under the Intergovernmental Panel on Climate Change's A1B scenario by approximately 30–35 years, although both models indicate rapid warming if geoengineering is not sustained. We find a broadly similar geographic distribution of the response to geoengineering in both models in terms of near-surface air temperature and mean June–August precipitation. The simulations also suggest that significant changes in regional climate would be experienced even if geoengineering was successful in maintaining global-mean temperature near current values.
- Published
- 2010
46. Nuclear winter
- Author
-
Alan Robock
- Subjects
Atmospheric Science ,Global and Planetary Change ,Nuclear winter ,Geography, Planning and Development ,Climate change ,Environmental science ,Atmospheric sciences - Published
- 2010
47. Impacts of land cover data quality on regional climate simulations
- Author
-
Elif Sertel, Alan Robock, and Cankut Ormeci
- Subjects
Atmospheric Science ,Meteorology ,Thematic Mapper ,Agricultural land ,Climatology ,Data quality ,Weather Research and Forecasting Model ,Available energy ,Environmental science ,Plant cover ,Climate model ,Land cover - Abstract
The land surface influences local, regional and global climate across many time scales. Accurate representation of land surfaces is an important factor for climate modelling studies because land surfaces control the partitioning of available energy and water. Here we introduce new, up-to-date and accurate land cover data for the Marmara Region, Turkey derived from Landsat Enhanced Thematic Mapper (ETM+) images into the Weather Research and Forecasting (WRF) model. We used several image processing techniques to create accurate land cover data from Landsat sensor images obtained between 2001 and 2005. By comparing the new land cover data with the default WRF land cover data, we found that there are two types of error in WRF land cover data that caused misrepresentation of the study region. WRF uses Global Land Cover Characteristics (GLCC) data created from images acquired during 1992 and 1993 and it does not reflect current land cover. And the GLCC includes misclassifications. As a result of these errors, GLCC data do not represent urban areas in the cities of Istanbul, Izmit and Bursa and there are spectral mixing problems between classes, e.g. croplands, urban areas and forests. We used WRF land cover and our new land cover data to conduct numerical simulations. Using meteorological station data within the study area, we found that simulation with the new land cover dataset produces more accurate temperature simulations for the region, thus demonstrating the importance of accurate land cover data. Copyright © 2009 Royal Meteorological Society
- Published
- 2009
48. Atmospheric effects and societal consequences of regional scale nuclear conflicts and acts of individual nuclear terrorism
- Author
-
Richard P. Turco, Alan Robock, Georgiy L. Stenchikov, Owen B. Toon, Luke D. Oman, Charles G. Bardeen, Department of Atmospheric and Oceanic Sciences [Boulder] (ATOC), University of Colorado [Boulder], Department of Atmospheric and Oceanic Sciences [Los Angeles] (AOS), University of California [Los Angeles] (UCLA), University of California-University of California, Department of Environmental Sciences [New Brunswick], School of Environmental and Biological Sciences [New Brunswick], Rutgers, The State University of New Jersey [New Brunswick] (RU), Rutgers University System (Rutgers)-Rutgers University System (Rutgers)-Rutgers, The State University of New Jersey [New Brunswick] (RU), and Rutgers University System (Rutgers)-Rutgers University System (Rutgers)
- Subjects
Atmospheric Science ,010504 meteorology & atmospheric sciences ,Meteorology ,Population ,Public debate ,Nuclear weapon ,010502 geochemistry & geophysics ,7. Clean energy ,01 natural sciences ,lcsh:Chemistry ,03 medical and health sciences ,Political science ,Development economics ,education ,030304 developmental biology ,0105 earth and related environmental sciences ,[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,0303 health sciences ,education.field_of_study ,Fissile material ,World War II ,16. Peace & justice ,lcsh:QC1-999 ,Megacity ,lcsh:QD1-999 ,13. Climate action ,lcsh:Physics ,Counterforce ,Nuclear terrorism - Abstract
We assess the potential damage and smoke production associated with the detonation of small nuclear weapons in modern megacities. While the number of nuclear warheads in the world has fallen by about a factor of three since its peak in 1986, the number of nuclear weapons states is increasing and the potential exists for numerous regional nuclear arms races. Eight countries are known to have nuclear weapons, 2 are constructing them, and an additional 32 nations already have the fissile material needed to build substantial arsenals of low-yield (Hiroshima-sized) explosives. Population and economic activity worldwide are congregated to an increasing extent in megacities, which might be targeted in a nuclear conflict. We find that low yield weapons, which new nuclear powers are likely to construct, can produce 100 times as many fatalities and 100 times as much smoke from fires per kt yield as previously estimated in analyses for full scale nuclear wars using high-yield weapons, if the small weapons are targeted at city centers. A single "small" nuclear detonation in an urban center could lead to more fatalities, in some cases by orders of magnitude, than have occurred in the major historical conflicts of many countries. We analyze the likely outcome of a regional nuclear exchange involving 100 15-kt explosions (less than 0.1% of the explosive yield of the current global nuclear arsenal). We find that such an exchange could produce direct fatalities comparable to all of those worldwide in World War II, or to those once estimated for a "counterforce" nuclear war between the superpowers. Megacities exposed to atmospheric fallout of long-lived radionuclides would likely be abandoned indefinitely, with severe national and international implications. Our analysis shows that smoke from urban firestorms in a regional war would rise into the upper troposphere due to pyro-convection. Robock et al. (2007) show that the smoke would subsequently rise deep into the stratosphere due to atmospheric heating, and then might induce significant climatic anomalies on global scales. We also anticipate substantial perturbations of global ozone. While there are many uncertainties in the predictions we make here, the principal unknowns are the type and scale of conflict that might occur. The scope and severity of the hazards identified pose a significant threat to the global community. They deserve careful analysis by governments worldwide advised by a broad section of the world scientific community, as well as widespread public debate.
- Published
- 2007
49. Climatic consequences of regional nuclear conflicts
- Author
-
Alan Robock, Luke D. Oman, Richard P. Turco, Georgiy L. Stenchikov, Owen B. Toon, Charles G. Bardeen, Department of Environmental Sciences [New Brunswick], School of Environmental and Biological Sciences [New Brunswick], Rutgers, The State University of New Jersey [New Brunswick] (RU), Rutgers University System (Rutgers)-Rutgers University System (Rutgers)-Rutgers, The State University of New Jersey [New Brunswick] (RU), Rutgers University System (Rutgers)-Rutgers University System (Rutgers), Department of Atmospheric and Oceanic Sciences [Boulder] (ATOC), University of Colorado [Boulder], Laboratory for Atmospheric and Space Physics [Boulder] (LASP), Department of Atmospheric and Oceanic Sciences [Los Angeles] (AOS), University of California [Los Angeles] (UCLA), and University of California-University of California
- Subjects
Smoke ,[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,Atmospheric Science ,010504 meteorology & atmospheric sciences ,Yield (finance) ,Climate change ,Subtropics ,010502 geochemistry & geophysics ,7. Clean energy ,01 natural sciences ,lcsh:QC1-999 ,lcsh:Chemistry ,Nuclear winter ,lcsh:QD1-999 ,13. Climate action ,Climatology ,Environmental science ,Climate model ,Precipitation ,Stratosphere ,lcsh:Physics ,0105 earth and related environmental sciences - Abstract
We use a modern climate model and new estimates of smoke generated by fires in contemporary cities to calculate the response of the climate system to a regional nuclear war between emerging third world nuclear powers using 100 Hiroshima-size bombs (less than 0.03% of the explosive yield of the current global nuclear arsenal) on cities in the subtropics. We find significant cooling and reductions of precipitation lasting years, which would impact the global food supply. The climate changes are large and long-lasting because the fuel loadings in modern cities are quite high and the subtropical solar insolation heats the resulting smoke cloud and lofts it into the high stratosphere, where removal mechanisms are slow. While the climate changes are less dramatic than found in previous "nuclear winter'' simulations of a massive nuclear exchange between the superpowers, because less smoke is emitted, the changes are more long-lasting because the older models did not adequately represent the stratospheric plume rise.
- Published
- 2007
50. CULTURE: Bob Dylan and Weather Imagery
- Author
-
Alan Robock
- Subjects
Atmospheric Science ,media_common.quotation_subject ,Art history ,Active listening ,Art ,Stylus ,media_common - Abstract
became a Bob Dylan fan in 1966 as a freshman at the University of Wisconsin— Madison the first time I heard him, listening to his second album, The Freewheelin’ Bob Dylan, played on my friend Gene Sherman’s record player [an ancient device in which a plastic disk with modulated groves spins on a platter at a frequency of 33.33 min−1 (0.556 s−1) and a stylus transfers the physical undulations into electrical signals]. I attended my first Dylan concert (he played with The Band) at the Boston Garden in 1974 while a graduate student and recently attended my
- Published
- 2005
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