26.05.2018

# New Publications

0 Comments

Tilmes, Simone; et al. (2018): CESM1(WACCM) Stratospheric Aerosol Geoengineering Large Ensemble (GLENS) Project

Tilmes, Simone; Richter, Jadwiga H.; Kravitz, Ben; MacMartin, Douglas G.; Mills, Michael J.; Simpson, Isla R. et al. (2018): CESM1(WACCM) Stratospheric Aerosol Geoengineering Large Ensemble (GLENS) Project. In Bulletin of the American Meteorological Society. DOI: 10.1175/BAMS-D-17-0267.1.

"This paper describes the stratospheric aerosol geoengineering large ensemble (GLENS) project, which promotes the use of a unique model dataset, performed with the Community Earth System Model, with the Whole Atmosphere Community Climate Model as its atmospheric component (CESM1(WACCM)), to investigate global and regional impacts of geoengineering. The performed simulations were designed to achieve multiple simultaneous climate goals, by strategically placing sulfur injections at four different locations in the stratosphere, unlike many earlier studies that targeted globally averaged surface temperature by placing injections in regions at or around the equator."

LINK


Read more »

11.05.2018

# New Publications

0 Comments

Richter, Jadwiga H.; et al. (2018): Stratospheric response in the first geoengineering simulation meeting multiple surface climate objectives

Richter, Jadwiga H.; Tilmes, Simone; Glanville, Anne A.; Kravitz, Ben; MacMartin, Douglas G.; Mills, Michael J. et al. (2018): Stratospheric response in the first geoengineering simulation meeting multiple surface climate objectives. In J. Geophys. Res. Atmos. DOI: 10.1029/2018JD028285.

"We describe here changes in stratospheric dynamics and chemistry in a first century‐long sulfate aerosol geoengineering simulation in which the mean surface temperature and the inter‐hemispheric and equator‐to‐pole surface temperature gradients were kept near their 2020 levels despite the RCP8.5 emission scenario. Simulations were carried out with the Community Earth System Model, version 1 with the Whole Atmosphere Community Climate Model as its atmospheric component (CESM1 (WACCM)) coupled to a feedback algorithm controlling the magnitude of sulfur dioxide (SO2) injections at four injection latitudes."

LINK


Read more »

03.04.2018

# New Publications

0 Comments

Carlin, Norman; James, Robert A. (2018): Geoengineering Research Under U.S. Law

Carlin, Norman; James, Robert A. (2018): Geoengineering Research Under U.S. Law. In Pratt's Energy Law Report 18 (3), pp. 67–75.

"The authors first divide the techniques under consideration between solar radiation management (aerosols in the stratosphere, or greater white surfaces below) and carbon dioxide removal (ocean iron fertilization (OIF) and other forms of carbon capture and sequestration). They detail the analysis required for an environmental impact statement (EIS) under the National Environmental Policy Act (NEPA), the California Environmental Quality Act (CEQA), and a variety of other U.S. statutes and common-law doctrines. "

LINK


Read more »

03.04.2018

# New Publications

0 Comments

MacMartin, Douglas G.; et al. (2018): Solar geoengineering as part of an overall strategy for meeting the 1.5°C Paris target

MacMartin, Douglas G.; Ricke, Katharine L.; Keith, David W. (2018): Solar geoengineering as part of an overall strategy for meeting the 1.5°C Paris target. In Phil. Trans. R. Soc. A 376 (2119), p. 20160454. DOI: 10.1098/rsta.2016.0454.

"We first provide a physical science review of current research, research trends and some of the key gaps in knowledge that would need to be addressed to support informed decisions. Next, since few climate model simulations have considered these limited-deployment scenarios, we synthesize prior results to assess the projected response if solar geoengineering were used to limit global mean temperature to 1.5°C above preindustrial in an overshoot scenario that would otherwise peak near 3°C. While there are some important differences, the resulting climate is closer in many respects to a climate where the 1.5°C target is achieved through mitigation alone than either is to the 3◦C climate with no geoengineering. This holds for both regional temperature and precipitation changes; indeed, there are no regions where a majority of models project that this moderate level of geoengineering would produce a statistically significant shift in precipitation further away from preindustrial levels."

LINK


Read more »

28.02.2018

# New Publications

0 Comments

Kleinschmitt, Christoph; et al. (2018): Sensitivity of the radiative forcing by stratospheric sulfur geoengineering to the amount and strategy of the SO2injection studied with the LMDZ-S3A model

Kleinschmitt, Christoph; Boucher, Olivier; Platt, Ulrich (2018): Sensitivity of the radiative forcing by stratospheric sulfur geoengineering to the amount and strategy of the SO2injection studied with the LMDZ-S3A model. In Atmos. Chem. Phys 18 (4), pp. 2769–2786. DOI: 10.5194/acp-18-2769-2018.

"In this study we use the atmospheric general circulation model LMDZ with the sectional aerosol module S3A to determine how the forcing efficiency depends on the injected amount of SO2, the injection height, and the spatio-temporal pattern of injection. We find that the forcing efficiency may decrease more drastically for larger SO2 injections than previously estimated. As a result, the net instantaneous radiative forcing does not exceed the limit of –2 W m−2 for continuous equatorial SO2 injections and it decreases (in absolute value) for injection rates larger than 20 Tg S yr−1. In contrast to other studies, the net radiative forcing in our experiments is fairly constant with injection height (in a range 17 to 23 km) for a given amount of SO2 injected."

LINK


Read more »

28.02.2018

# New Publications

0 Comments

Visioni, Daniele; et al. (2018): Sulfur deposition changes under sulfate geoengineering conditions. Quasi-biennial oscillation effects on the transport and lifetime of stratospheric aerosols

Visioni, Daniele; Pitari, Giovanni; Tuccella, Paolo; Curci, Gabriele (2018): Sulfur deposition changes under sulfate geoengineering conditions. Quasi-biennial oscillation effects on the transport and lifetime of stratospheric aerosols. In Atmos. Chem. Phys 18 (4), pp. 2787–2808. DOI: 10.5194/acp-18-2787-2018.

"Among several possible environmental side effects, the increase in sulfur deposition deserves additional investigation. In this study we present results from a composition–climate coupled model (University of L'Aquila Composition-Chemistry Model, ULAQ-CCM) and a chemistry-transport model (Goddard Earth Observing System Chemistry-Transport Model, GEOS-Chem), assuming a sustained lower-stratospheric equatorial injection of 8 Tg SO2 yr−1. Total S deposition is found to globally increase by 5.2 % when sulfate geoengineering is deployed, with a clear interhemispheric asymmetry (+3.8 and +10.3 % in the Northern Hemisphere (NH) and the Southern Hemisphere (SH), due to +2.2 and +1.8 Tg S yr−1, respectively)."

LINK


Read more »

18.02.2018

# Media

0 Comments

Wallstreet Journal: A Big-Sky Plan to Cool the Planet

"Pumping aerosols into the stratosphere may buy us more time, but it’s no substitute for cutting carbon emissions—and we still don’t know enough to do it responsibly."

LINK


Read more »

10.02.2018

# New Publications

0 Comments

Jones, Anthony C.; et al. (2018): Regional climate impacts of stabilizing global warming at 1.5 K using solar geoengineering

Jones, Anthony C.; Hawcroft, Matthew K.; Haywood, James M.; Jones, Andy; Guo, Xiaoran; Moore, John C. (2018): Regional climate impacts of stabilizing global warming at 1.5 K using solar geoengineering. In Earth's Future. DOI: 10.1002/2017EF000720.

"In this study, we use a global climate model to investigate the climatic impacts of using solar geoengineering by stratospheric aerosol injection to stabilize global-mean temperature at 1.5 K for the duration of the 21st century against 3 scenarios spanning the range of plausible greenhouse gas mitigation pathways (RCP2.6, RCP4.5, RCP8.5)."

LINK


Read more »

26.01.2018

# New Publications

0 Comments

Irvine, Peter J.; et al. (2018): Brief communication. Understanding solar geoengineering's potential to limit sea level rise requires attention from cryosphere experts

Irvine, Peter J.; Keith, David W.; Moore, John (2018): Brief communication. Understanding solar geoengineering's potential to limit sea level rise requires attention from cryosphere experts. In The Cryosphere Discuss., pp. 1–15. DOI: 10.5194/tc-2017-279.

"Stratospheric aerosol geoengineering, a form of solar geoengineering, is a proposal to add a reflective layer of aerosol to the stratosphere to reduce net radiative forcing and so to reduce the risks of climate change. Solar geoengineering could reduce temperatures and so slow melt, but the efficacy of solar geoengineering at offsetting changes to the cryosphere is uncertain. For example, shortwave forcing acts more strongly on the surface than longwave forcing so solar geoengineering would reduce surface melt more effectively but would also suppress the global hydrological cycle potentially reducing accumulation on glaciers."

LINK


Read more »

20.01.2018

# New Publications

0 Comments

Gunderson, Ryan; et al. (2018): A Critical Examination of Geoengineering. Economic and Technological Rationality in Social Context

Gunderson, Ryan; Petersen, Brian; Stuart, Diana (2018): A Critical Examination of Geoengineering. Economic and Technological Rationality in Social Context (Sustainability, 10).

"Substantial emissions reductions, unlike geoengineering, are costly, rely more on social-structural than technical changes, and are at odds with the current social order. Because of this, geoengineering will increasingly be considered a core response to climate change. In light of Herbert Marcuse’s critical theory, the promotion of geoengineering as a market-friendly and high-tech strategy is shown to reflect a society that cannot set substantive aims through reason and transforms what should be considered means (technology and economic production) into ends themselves. Such a condition echoes the first-generation Frankfurt School’s central thesis: instrumental rationality remains irrational."

LINK


Read more »