Academic Publications

2016
Pete Irvine, Ben Kravitz, Mark Lawrence, and Helene Muri. 7/2016. “An overview of the Earth system science of solar geoengineering.” Wiley Interdisciplinary Reviews: Climate Change. Publisher's VersionAbstract

Solar geoengineering has been proposed as a means to cool the Earth by increasing the reflection of sunlight back to space, for example, by injecting reflective aerosol particles (or their precursors) into the lower stratosphere. Such proposed techniques would not be able to substitute for mitigation of greenhouse gas (GHG) emissions as a response to the risks of climate change, as they would only mask some of the effects of global warming. They might, however, eventually be applied as a complementary approach to reduce climate risks. Thus, the Earth system consequences of solar geoengineering are central to understanding its potentials and risks. Here we review the state-of-the-art knowledge about stratospheric sulfate aerosol injection and an idealized proxy for this, ‘sunshade geoengineering,’ in which the intensity of incoming sunlight is directly reduced in models. Studies are consistent in suggesting that sunshade geoengineering and stratospheric aerosol injection would generally offset the climate effects of elevated GHG concentrations. However, it is clear that a solar geoengineered climate would be novel in some respects, one example being a notably reduced hydrological cycle intensity. Moreover, we provide an overview of nonclimatic aspects of the response to stratospheric aerosol injection, for example, its effect on ozone, and the uncertainties around its consequences. We also consider the issues raised by the partial control over the climate that solar geoengineering would allow. Finally, this overview highlights some key research gaps in need of being resolved to provide sound basis for guidance of future decisions around solar geoengineering.

Robert E. Kopp, Rachael Shwom, Gernot Wagner, and Jiacan Yuan. 7/2016. “Tipping elements and climate-economic shocks: Pathways toward integrated assessment.” Earth's Future. Publisher's VersionAbstract

The literature on the costs of climate change often draws a link between climatic ‘tipping points’ and large economic shocks, frequently called ‘catastrophes’. The phrase ‘tipping points’ in this context can be misleading. In popular and social scientific discourse, ‘tipping points’ involve abrupt state changes. For some climatic ‘tipping points,’ the commitment to a state change may occur abruptly, but the change itself may be rate-limited and take centuries or longer to realize. Additionally, the connection between climatic ‘tipping points’ and economic losses is tenuous, though emerging empirical and process-model-based tools provide pathways for investigating it. We propose terminology to clarify the distinction between ‘tipping points’ in the popular sense, the critical thresholds exhibited by climatic and social ‘tipping elements,’ and ‘economic shocks’. The last may be associated with tipping elements, gradual climate change, or non-climatic triggers. We illustrate our proposed distinctions by surveying the literature on climatic tipping elements, climatically sensitive social tipping elements, and climate-economic shocks, and we propose a research agenda to advance the integrated assessment of all three.

David Keith, Gernot Wagner, and Juan Moreno-Cruz. 6/24/2016. “Modeling the effects of climate engineering.” Science, 352, 6293, Pp. 1526-1527. Publisher's Version keith_et_al._-_2016_-_modeling_the_effects_of_climate_engineering.pdf
Lee Miller, Vaclav Smil, Gernot Wagner, and David Keith. 6/20/2016. “Stated estimates for city-integrated wind and solar PV are too high.” Science eLetter. Publisher's Version
Joshua Horton and Jesse Reynolds. 3/18/2016. “The International Politics of Climate Engineering: A Review and Prospectus for International Relations.” The Oxford University Press. Publisher's VersionAbstract

Proposed large-scale intentional interventions in natural systems in order to counter climate change, typically called “climate engineering” or “geoengineering,” stand to dramatically alter the international politics of climate change and potentially much more. There is currently a significant and growing literature on the international politics of climate engineering. However, it has been produced primarily by scholars from outside the discipline of International Relations (IR). We are concerned that IR scholars are missing a critical opportunity to offer insights into, and perhaps help shape, the emerging international politics of climate engineering. To that end, the primary goal of this paper is to call the attention of the IR community to these developments. Thus, we offer here an overview of the existing literature on the international politics of climate engineering and a preliminary assessment of its strengths and lacunae. We trace several key themes in this corpus, including problem structure, the concern that climate engineering could undermine emissions cuts, the potentially “slippery slope” of research and development, unilateral implementation, interstate conflict, militarization, rising tensions between industrialized and developing countries, and governance challenges and opportunities. The international politics of climate engineering is then considered through the lenses of the leading IR theories (Realism, Institutionalism, Liberalism, and Constructivism), exploring both what they have contributed and possible lines of future inquiry. Disciplinary IR scholars should have much to say on a number of topics related to climate engineering, including its power and transformational potentials, the possibility of counter-climate engineering, issues of institutional design, international law, and emergent practices. We believe that it is incumbent on the IR community, whose defining focus is international relations, to turn its attention to these unprecedented technologies and to the full scope of possible ramifications they might have for the international system.

Joshua Horton, David Keith, and Matthias Honegger. 2016. “Implications of the Paris Agreement for Carbon Dioxide Removal and Solar Geoengineering.” Policy Brief, Harvard Project on Climate Agreements, Belfer Center for Science and International Affairs, Harvard Kennedy School. Publisher's Version horton_et_al._-_2016_-_implications_of_the_paris_agreement_for_carbon_dio.pdf
Caitlin G. McCormack, Wanda Born, Peter Irvine, Eric P. Achterberg, Tatsuya Amano, Jeff Ardron, Pru N. Foster, Jean-Pierre Gattuso, Stephen J. Hawkins, Erica Hendy, W. Daniel Kissling, Salvador E. Lluch-Cota, Eugene J. Murphy, Nick Ostle, Nicholas J.P. Owens, R. Ian Perry, Hans O. Pörtner, Robert J. Scholes, Frank M. Schurr, Oliver Schweiger, Josef Settele, Rebecca K. Smith, Sarah Smith, Jill Thompson, Derek P. Tittensor, Mark van Kleunen, Chris Vivian, Katrin Vohland, Rachel Warren, Andrew R. Watkinson, Steve Widdicombe, Phillip Williamson, Emma Woods, Jason J. Blackstock, and William J. Sutherland. 2016. “Key impacts of climate engineering on biodiversity and ecosystems, with priorities for future research.” Journal of Integrative Environmental Sciences, Pp. 1-26. Publisher's VersionAbstract

Climate change has significant implications for biodiversity and ecosystems. With slow progress towards reducing greenhouse gas emissions, climate engineering (or ‘geoengineering’) is receiving increasing attention for its potential to limit anthropogenic climate change and its damaging effects. Proposed techniques, such as ocean fertilization for carbon dioxide removal or stratospheric sulfate injections to reduce incoming solar radiation, would significantly alter atmospheric, terrestrial and marine environments, yet potential side-effects of their implementation for ecosystems and biodiversity have received little attention. A literature review was carried out to identify details of the potential ecological effects of climate engineering techniques. A group of biodiversity and environmental change researchers then employed a modified Delphi expert consultation technique to evaluate this evidence and prioritize the effects based on the relative importance of, and scientific understanding about, their biodiversity and ecosystem consequences. The key issues and knowledge gaps are used to shape a discussion of the biodiversity and ecosystem implications of climate engineering, including novel climatic conditions, alterations to marine systems and substantial terrestrial habitat change. This review highlights several current research priorities in which the climate engineering context is crucial to consider, as well as identifying some novel topics for ecological investigation.

mccormack_et_al._-_2016_-_key_impacts_of_climate_engineering_on_biodiversity.pdf
Joshua Horton and David Keith. 2016. “Solar Geoengineering and Obligations to the Global Poor.” In Climate Justice and Geoengineering: Ethics and Policy in the Atmospheric Anthropocene, edited by Christopher J. Preston. London: Rowman & Littlefield. Publisher's Version horton_and_keith_2016.pdf
Lee Miller and Axel Kleidon. 2016. “Wind speed reductions by large-scale wind turbine deployments lower turbine efficiencies and set low generation limits.” Proceedings of the National Academy of Sciences. Publisher's VersionAbstract

Wind turbines generate electricity by removing kinetic energy from the atmosphere. Large numbers of wind turbines are likely to reduce wind speeds, which lowers estimates of electricity generation from what would be presumed from unaffected conditions. Here, we test how well wind power limits that account for this effect can be estimated without explicitly simulating atmospheric dynamics. We first use simulations with an atmospheric general circulation model (GCM) that explicitly simulates the effects of wind turbines to derive wind power limits (GCM estimate), and compare them to a simple approach derived from the climatological conditions without turbines [vertical kinetic energy (VKE) estimate]. On land, we find strong agreement between the VKE and GCM estimates with respect to electricity generation rates (0.32 and 0.37 We m−2) and wind speed reductions by 42 and 44%. Over ocean, the GCM estimate is about twice the VKE estimate (0.59 and 0.29 We m−2) and yet with comparable wind speed reductions (50 and 42%). We then show that this bias can be corrected by modifying the downward momentum flux to the surface. Thus, large-scale limits to wind power use can be derived from climatological conditions without explicitly simulating atmospheric dynamics. Consistent with the GCM simulations, the approach estimates that only comparatively few land areas are suitable to generate more than 1 We m−2 of electricity and that larger deployment scales are likely to reduce the expected electricity generation rate of each turbine. We conclude that these atmospheric effects are relevant for planning the future expansion of wind power.

2015
Jana Sillmann, Timothy M. Lenton, Anders Levermann, Konrad Ott, Mike Hulme, Francois Benduhn, and Joshua Horton. 2015. “Climate Emergencies Do Not Justify Engineering the Climate.” Nature Climate Change. Publisher's Version
Jason J. Blackstock, Neil Craik, Jack Doughty, and Joshua Horton. 2015. “Designing Procedural Mechanisms for the Governance of Solar Radiation Management Field Experiments: Workshop Report”. Publisher's Version
Joshua Horton. 2015. “The Emergency Framing of Solar Geoengineering: Time for a Different Approach.” The Anthropocene Review. Publisher's Version
Hossein Safaei and David Keith. 2015. “How much bulk energy storage is needed to decarbonize electricity?” Energy and Environmental Science, 8, 12, Pp. 3409-3417. Publisher's Version ees_safaei-keith_bulk_storage_2015.pdf
Steven R. H. Barrett, Raymond L. Speth, Sebastian D. Eastham, Irene C. Dedoussi, Akshay Ashok, Robert Malina, and David Keith. 2015. “Impact of the Volkswagen emissions control defeat device on US public health.” Environmental Research Letters, 10, 11, Pp. 114005. Publisher's Version barrett_et_al._-_2015_-_impact_of_the_volkswagen_emissions_control_defeat_.pdf
Joshua Horton, Andrew Parker, and David Keith. 2015. “Liability for Solar Geoengineering: Historical Precedents, Contemporary Innovations, and Governance Possibilities.” NYU Environmental Law Journal, 22, Pp. 225-273. Publisher's Version 176.horton.keith_.liabilityforsolargeoengineering.pdf
Debra Weisenstein, David Keith, and John Dykema. 2015. “Solar geoengineering using solid aerosol in the stratosphere.” Atmospheric Chemistry and Physics, 15, Pp. 11835-11859. Publisher's Version weisenstein_et_al._-_2015_-_solar_geoengineering_using_solid_aerosol_in_the_st.pdf
David Keith and Douglas G. MacMartin. 2015. “A temporary, moderate and responsive scenario for solar geoengineering.” Nature Climate Change, 5. Publisher's Version 174.keith_.macmartin.atemporarymoderateandresponsivescenarioforsolargeoengineering.pdf
Lee Miller, Nathaniel A. Brunsell, David B. Mechem, Fabian Gans, Andrew J. Monaghan, Robert Vautard, David Keith, and Axel Kleidon. 2015. “Two methods for estimating limits to large-scale wind power generation.” Proceedings of the National Academy of Sciences of the United States, 112, Pp. 11169–11174. Publisher's Version miller_et_al._-_2015_-_two_methods_for_estimating_limits_to_large-scale_w.pdf
David Keith and Andy Parker. 2015. “Will solar geoengineering help us manage the risks of climate change?” Our world and us: How our environment and our societies will change, Pp. 76-92. Publisher's Version 175.keith_.parker.willsolargeoengineeringhelpusmanagetherisksofclimatechange.pdf
Kerry Emanuel, Frauke Hoss, David Keith, Zhiming Kuang, Julie Lundquist, and Lee Miller. 2015. “Workshop on Climate Effects of Wind Turbines, American Meteorological Society”. Publisher's Version emanuel_et_al._-_2015_-_workshop_on_climate_effects_of_wind_turbines_amer.pdf

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