28.08.2015

# New Publications

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V. N. Aswathy; et al. (2015): Climate extremes in multi-model simulations of stratospheric aerosol and marine cloud brightening climate engineering

V. N. Aswathy; Boucher, O.; Quaas, M.; Niemeier, U.; Muri, H.; Mülmenstädt, J.; Quaas, J. (2015): Climate extremes in multi-model simulations of stratospheric aerosol and marine cloud brightening climate engineering. In Atmos. Chem. Phys. 15 (16), pp. 9593–9610. DOI 10.5194/acp-15-9593-2015 (final paper)

"Simulations from a multi-model ensemble for the RCP4.5 climate change scenario for the 21st century, and for two solar radiation management (SRM) schemes (stratospheric sulfate injection (G3), SULF and marine cloud brightening by sea salt emission SALT) have been analysed in terms of changes in the mean and extremes of surface air temperature and precipitation. The climate engineering and termination periods are investigated. During the climate engineering period, both schemes, as intended, offset temperature increases by about 60 % globally, but are more effective in the low latitudes and exhibit some residual warming in the Arctic (especially in the case of SALT which is only applied in the low latitudes)."

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27.08.2015

# New Publications

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Sánchez, Joan-Pau; McInnes, Colin R. (2015): Optimal Sunshade Configurations for Space-Based Geoengineering near the Sun-Earth L1 Point

Sánchez, Joan-Pau; McInnes, Colin R. (2015): Optimal Sunshade Configurations for Space-Based Geoengineering near the Sun-Earth L1 Point. In PloS one 10 (8), pp. e0136648. DOI 10.1371/journal.pone.0136648  

"In particular, the paper revisits the concept of deploying a large sunshade or occulting disk at a static position near the Sun-Earth L1 Lagrange equilibrium point. Among the solar radiation management methods that have been proposed thus far, space-based concepts are generally seen as the least timely, albeit also as one of the most efficient."

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22.08.2015

# New Publications

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Crook, J.; et al. (2015): A Comparison of Temperature and Precipitation Responses to Different Earth Radiation Management Geoengineering Schemes

Crook, J.; Jackson, L. S.; Osprey, S. M.; Forster, P. M. (2015): A Comparison of Temperature and Precipitation Responses to Different Earth Radiation Management Geoengineering Schemes. In J. Geophys. Res. Atmos., pp. n/a-n/a. DOI 10.1002/2015JD023269

"We compare six different radiation management schemes that use surface, troposphere and stratosphere interventions in a single climate model in which we projected future climate from 2020 to 2099 based on RCP4.5. We analyze the surface air temperature responses to determine how effective the schemes are at returning temperature to its 1986-2005 climatology and analyze precipitation responses to compare side effects."

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22.08.2015

# New Publications

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Grandey, B. S.; Wang, C. (2015): Enhanced marine sulphur emissions offset global warming and impact rainfall

Grandey, B. S.; Wang, C. (2015): Enhanced marine sulphur emissions offset global warming and impact rainfall. In Scientific reports 5, p. 13055–13055. DOI 10.1038/srep13055

"Artificial fertilisation of the ocean has been proposed as a possible geoengineering method for removing carbon dioxide from the atmosphere. The associated increase in marine primary productivity may lead to an increase in emissions of dimethyl sulphide (DMS), the primary source of sulphate aerosol over remote ocean regions, potentially causing direct and cloud-related indirect aerosol effects on climate."

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20.08.2015

# Media

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Phys.org: Study finds geoengineering technique would not stop sea level rise

Media response to Applegate, Patrick J.; Keller, Klaus (2015). "Albedo modification, an emerging technology with the potential to offset some aspects of climate change, shouldn't be counted on as a short-term solution to stop rising global sea levels, according to a new study from Penn State geoscientists."

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20.08.2015

# New Publications

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Applegate, Patrick J.; Keller, Klaus (2015): How effective is albedo modification (solar radiation management geoengineering) in preventing sea-level rise from the Greenland Ice Sheet?

Applegate, Patrick J.; Keller, Klaus (2015): How effective is albedo modification (solar radiation management geoengineering) in preventing sea-level rise from the Greenland Ice Sheet? In Environ. Res. Lett. 10 (8), p. 84018–84018. DOI 10.1088/1748-9326/10/8/084018

"Here, we assess AM's ability to reduce GIS sea-level contributions over decades to centuries, using a simplified ice sheet model. We drive this model using a business-as-usual base temperature forcing scenario, as well as scenarios that reflect AM-induced temperature stabilization or temperature drawdown."

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18.08.2015

# New Publications

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Niemeier, U.; Timmreck, C. (2015): What is the limit of climate engineering by stratospheric injection of SO2?

Niemeier, U.; Timmreck, C. (2015): What is the limit of climate engineering by stratospheric injection of SO2? In Atmos. Chem. Phys. 15 (16), pp. 9129–9141. DOI 10.5194/acp-15-9129-2015.

"We estimate the reliability of our results through consideration of various injection strategies and from comparison with results obtained from other models. Our calculations show that the efficiency of such a geoengineering method, expressed as the ratio between sulfate aerosol forcing and injection rate, decays exponentially. This result implies that the sulfate solar radiation management strategy required to keep temperatures constant at that anticipated for 2020, while maintaining business as usual conditions, would require atmospheric injections of approximately 45 Tg(S) yr−1 (±15 % or 7 Tg(S) yr−1) at a height corresponding to 60 hPa."

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18.08.2015

# New Publications

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MacMartin, Douglas G.; et al. (2015): On solar geoengineering and climate uncertainty

MacMartin, Douglas G.; Kravitz, Ben; Rasch, Philip J. (2015): On solar geoengineering and climate uncertainty. In Geophys. Res. Lett., pp. n/a. DOI 10.1002/2015GL065391.

"We explore the effects of geoengineering on one source of climate system uncertainty by evaluating the inter-model-spread across 12 climate models participating in the Geoengineering Model Intercomparison project (GeoMIP). The model-spread in simulations of climate change and the model-spread in the response to solar geoengineering are not additive but rather partially cancel."

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18.08.2015

# New Publications

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Laakso, A.; et al. (2015): Radiative and climate impacts of a large volcanic eruption during stratospheric sulfur geoengineering

Laakso, A.; Kokkola, H.; Partanen, A.-I.; Niemeier, U.; Timmreck, C.; Lehtinen, K. E. J. et al. (2015): Radiative and climate impacts of a large volcanic eruption during stratospheric sulfur geoengineering. In Atmos. Chem. Phys. Discuss. 15 (15), pp. 21837–21881. DOI 10.5194/acpd-15-21837-2015.

"Here we employ a global aerosol-climate model and an earth system model to study the radiative and climate impacts of an erupting volcano during solar radiation management (SRM). According to our simulations, the radiative impacts of an eruption and SRM are not additive: in the simulated case of concurrent eruption and SRM, the peak increase in global forcing is about 40 % lower compared to a corresponding eruption into a clean background atmosphere."

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05.08.2015

# New Publications

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Parkes, B.; et al. (2015): Crop failure rates in a geoengineered climate: impact of climate change and marine cloud brightening

Parkes, B.; Challinor, A.; Nicklin, K. (2015): Crop failure rates in a geoengineered climate: impact of climate change and marine cloud brightening. In Environ. Res. Lett. 10 (8), p. 084003–84003. DOI 10.1088/1748-9326/10/8/084003.

"We investigate the impact of a future climate and a potential geoengineering scheme on the number of crop failures in two regions, Northeastern China and West Africa. Climate change associated with a doubling of atmospheric carbon dioxide increases the number of crop failures in Northeastern China while reducing the number of crop failures in West Africa"

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