Reference

Oschlies et al 2010: Climate engineering by artificial upwelling -- Channeling the sorcerer's apprentive

2010-02-16T05:43:46Z

Climate engineering by artificial ocean upwelling: Channelling the sorcerer's apprentice

A. Oschlies

Leibniz‐Institut für Meereswissenschaften an der Universität Kiel (IFM‐GEOMAR), Kiel, Germany

M. Pahlow

Leibniz‐Institut für Meereswissenschaften an der Universität Kiel (IFM‐GEOMAR), Kiel, Germany

A. Yool

National Oceanography Centre Southampton, Southampton, UK

R. J. Matear

CSIRO Marine Laboratories, Hobart, Tasmania, Australia

Recent suggestions to reduce the accumulation of anthropogenic carbon dioxide in the atmosphere have included ocean fertilization by artificial upwelling. Our coupled carbon‐climate model simulations suggest that artificial upwelling may, under most optimistic assumptions, be able to sequester atmospheric CO2 at a rate of about 0.9 PgC/yr. However, the model predicts that about 80% of the carbon sequestered is stored on land, as a result of reduced respiration at lower air temperatures brought about by upwelling of cold waters. This remote and distributed carbon sequestration would make monitoring and verification particularly challenging. A second caveat predicted by our simulations is that whenever artificial upwelling is stopped, simulated surface temperatures and atmospheric CO2 concentrations rise quickly and for decades to centuries to levels even somewhat higher than experienced in a world that never engaged in artificial upwelling.

Glossary

2010-03-06T20:23:58Z

Glossary

Geo-engineering

Also Climate Intervention or Climate Engineering

These terms are bandied about considerably and often used interchangeably, resulting in substantial confusion in the exchange of ideas concerning the investigation into and efforts to address the consequences of greenhouse gas emissions on the climate. Several groups have suggested use of the terms ‘climate intervention’ or 'climate engineering' to distinguish this activity from large scale civil engineering projects which have classically been called geoengineering.

The American Meteorological Society (AMS), in their Policy Statement on Geoengineering, defines geoengineering as large-scale efforts to deliberately manipulate physical, chemical, or biological aspects of the climate system. In the particular context of their report, geoengineering is intended to counteract the consequences of increasing greenhouse gas emissions. This definition is similar to that used by the Royal Society (UK) in their report Geoengineering the Climate.

The CRF stresses that these techniques are but one potential component in a comprehensive approach to strategy development and risk assessment in the effort to slow climate change and its impact on society.

Robock et al 2010: A Test for Geoengineering?

2010-01-29T07:06:44Z

Science 29 January 2010:
Vol. 327. no. 5965, pp. 530 - 531
DOI: 10.1126/science.1186237

Perspectives

Atmospheric Science:

A Test for Geoengineering?

Alan Robock,¹ Martin Bunzl,² Ben Kravitz,¹ Georgiy L. Stenchikov³

¹ Department of Environmental Sciences, Rutgers University, 14 College Farm Road, New Brunswick, NJ 08901, USA.
² Department of Philosophy, Rutgers University, 191 Ryders Lane, New Brunswick, NJ 08901, USA.
³ Division of Physical Sciences and Engineering, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia.

E-mail: robock@envsci.rutgers.edu

http://www.sciencemag.org/cgi/content/full/327/5965/530

Scientific and political interest in the possibility of geoengineeringthe climate is rising (1). There are currently no means of implementinggeoengineering, but if a viable technology is produced in thenext decade, how could it be tested? We argue that geoengineeringcannot be tested without full-scale implementation. The initialproduction of aerosol droplets can be tested on a small scale,but how they will grow in size (which determines the injectionrate needed to produce a particular cooling) can only be testedby injection into an existing aerosol cloud, which cannot beconfined to one location. Furthermore, weather and climate variabilitypreclude observation of the climate response without a large,decade-long forcing. Such full-scale implementation could disruptfood production on a large scale.

Blackstock and Long 2010: The Politics of Geoengineering

2010-01-29T06:55:52Z

Science 29 January 2010:
Vol. 327. no. 5965, p. 527
DOI: 10.1126/science.1183877

Policy Forum

Climate Change:

The Politics of Geoengineering

Jason J. Blackstock¹^,2^,* and Jane C. S. Long³

¹ International Institute for Applied Systems Analysis, Laxenburg, A2361, Austria.
² Centre for International Governance Innovation, Waterloo, N2L 6C2, Canada.
³ Lawrence Livermore National Laboratory, Livermore, CA 94550, USA (DE-AC52-07NA27344).

^* Author for correspondence: jjb@iiasa.ac.at

http://www.sciencemag.org/cgi/content/full/327/5965/527
http://www.sciencemag.org/cgi/content/full/327/5965/527

Despite mounting evidence that severe climate change could emergerapidly, the global reduction of carbon emissions remains alarminglyelusive (1, 2). As a result, concerned scientists are now askingwhether geoengineering—the intentional, large-scale alterationof the climate system—might be able to limit climate changeimpacts. Recent prominent reviews have emphasized that suchschemes are fraught with uncertainties and potential negativeeffects and, thus, cannot be a substitute for comprehensivemitigation (3, 4). But as unabated climate change could itselfprove extremely risky, these reviews also recommend expandinggeoengineering research. As such research is considered (5–7), a process for ensuring global transparency and cooperationis needed.

Keith et al 2010: Research on sun block needed now

2010-01-28T06:44:11Z

Nature 463, 426-427 (28 January 2010) | doi:10.1038/463426a; Published online 27 January 2010

Research on global sun block needed now

David W. Keith, Edward Parson & M. Granger Morgan

Geoengineering studies of solar-radiation management should begin urgently, argue David W. Keith, Edward Parson and M. Granger Morgan — before a rogue state decides to act alone.

Summary

Field testing is required to understand the risks of solar-radiation management (SRM)
Linked activities must create norms and understanding for international governance of SRM
If SRM is unworkable, the sooner we know, the less moral hazard it poses

http://www.nature.com/nature/journal/v463/n7280/full/463426a.html

Heckendorn et al 2009: The impact of geoengineering aerosols on stratospheric temperature and ozone

2009-11-13T07:16:22Z

The impact of geoengineering aerosols on stratospheric temperature and ozone

P Heckendorn et al 2009 Environ. Res. Lett. 4 045108 (12pp)

The impact of geoengineering aerosols on stratospheric temperature and ozone

P Heckendorn et al 2009 Environ. Res. Lett. 4 045108 (12pp) doi: 10.1088/1748-9326/4/4/045108

PDF (600 KB) | HTML | References

P Heckendorn¹, D Weisenstein², S Fueglistaler³, B P Luo¹, E Rozanov^1,4, M Schraner¹, L W Thomason⁵ and T Peter¹
¹ Institute for Atmospheric and Climate Science, ETH Zurich, 8092 Zurich, Switzerland
² AER, Lexington, MA, USA
³ DAMTP, University of Cambridge, UK
⁴ PMOD-WRC, Davos, Switzerland
⁵ NASA Langley Research Center, Hampton, VA, USA
E-mail: patricia.heckendorn@env.ethz.chPart of Focus on Climate Engineering: Intentional Intervention in the Climate System

Abstract. Anthropogenic greenhouse gas emissions are warming the global climate at an unprecedented rate. Significant emission reductions will be required soon to avoid a rapid temperature rise. As a potential interim measure to avoid extreme temperature increase, it has been suggested that Earth's albedo be increased by artificially enhancing stratospheric sulfate aerosols. We use a 3D chemistry climate model, fed by aerosol size distributions from a zonal mean aerosol model, to simulate continuous injection of 1–10 Mt/a into the lower tropical stratosphere. In contrast to the case for all previous work, the particles are predicted to grow to larger sizes than are observed after volcanic eruptions. The reason is the continuous supply of sulfuric acid and hence freshly formed small aerosol particles, which enhance the formation of large aerosol particles by coagulation and, to a lesser extent, by condensation. Owing to their large size, these particles have a reduced albedo. Furthermore, their sedimentation results in a non-linear relationship between stratospheric aerosol burden and annual injection, leading to a reduction of the targeted cooling. More importantly, the sedimenting particles heat the tropical cold point tropopause and, hence, the stratospheric entry mixing ratio of H₂O increases. Therefore, geoengineering by means of sulfate aerosols is predicted to accelerate the hydroxyl catalyzed ozone destruction cycles and cause a significant depletion of the ozone layer even though future halogen concentrations will be significantly reduced.

Received 29 May 2009, accepted for publication 28 October 2009
Published 13 November 2009

MacCracken 2009: On the possible use of geoengineering to moderate specific climate change impacts

2009-10-12T07:01:47Z

On the possible use of geoengineering to moderate specific climate change impacts

Michael C MacCracken 2009 Environ. Res. Lett. 4 045107 (14pp)

Michael C MacCracken
Climate Institute, Washington, DC 20006, USA

http://www.iop.org/EJ/abstract/1748-9326/4/4/045107

Abstract. With significant reductions in emissions likely to require decades and the impacts of projected climate change likely to become more and more severe, proposals for taking deliberate action to counterbalance global warming have been proposed as an important complement to reducing emissions. While a number of geoengineering approaches have been proposed, each introduces uncertainties, complications and unintended consequences that have only begun to be explored. For limiting and reversing global climate change over periods of years to decades, solar radiation management, particularly injection of sulfate aerosols into the stratosphere, has emerged as the leading approach, with mesospheric reflectors and satellite deflectors also receiving attention. For a number of reasons, tropospheric approaches to solar radiation management present greater challenges if the objective is to reduce the increase in global average temperature. However, such approaches have a number of advantages if the objective is to alleviate specific consequences of climate change expected to cause significant impacts for the environment and society. Among the most damaging aspects of the climate that might be countered are: the warming of low-latitude oceans that observations suggest contribute to more intense tropical cyclones and coral bleaching; the amplified warming of high latitudes and the associated melting of ice that has been accelerating sea level rise and altering mid-latitude weather; and the projected reduction in the loading and cooling influence of sulfate aerosols, which has the potential to augment warming sufficient to trigger methane and carbon feedbacks. For each of these impacts, suitable scientific, technological, socioeconomic, and governance research has the potential to lead to tropospheric geoengineering approaches that, with a well-funded research program, could begin playing a moderating role for some aspects of climate change within a decade.

Received 8 May 2009, accepted for publication 12 October 2009
Published 30 October 2009

Hangx and Spiers 2009: Coastal spreading of olivine to control atmospheric CO2 concentrations: A critical analysis of viability

2009-12-01T06:55:18Z

Coastal spreading of olivine to control atmospheric CO₂ concentrations: A critical analysis of viability

Suzanne J.T. Hangx and Christopher J. Spiers

HPT-laboratory, Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Budapestlaan 4, P.O. Box 80021, 3508 TA Utrecht, The Netherlands

Received 11 February 2009;

revised 24 June 2009;

accepted 2 July 2009.

Available online 3 August 2009.

<link>

Abstract

Qualitative proposals to control atmospheric CO₂ concentrations by spreading crushed olivine rock along the Earth's coastlines, thereby accelerating weathering reactions, are presently attracting considerable attention. This paper provides a critical evaluation of the concept, demonstrating quantitatively whether or not it can contribute significantly to CO₂ sequestration. The feasibility of the concept depends on the rate of olivine dissolution, the sequestration capacity of the dominant reaction, and its CO₂ footprint. Kinetics calculations show that offsetting 30% of worldwide 1990 CO₂ emissions by beach weathering means distributing of 5.0 Gt of olivine per year. For mean seawater temperatures of 15–25 °C, olivine sand (300 μm grain size) takes 700–2100 years to reach the necessary steady state sequestration rate and is therefore of little practical value. To obtain useful, steady state CO₂ uptake rates within 15–20 years requires grain sizes <10 μm. However, the preparation and movement of the required material poses major economic, infrastructural and public health questions. We conclude that coastal spreading of olivine is not a viable method of CO₂ sequestration on the scale needed. The method certainly cannot replace CCS technologies as a means of controlling atmospheric CO₂ concentrations.

Keywords: CO₂ sequestration; Olivine; Mineralisation; Weathering

Hegerl and Solomon 2009: Climate Change - Risks of Climate Engineering

2009-08-06T06:37:58Z

Perspectives

Climate Change:

Risks of Climate Engineering

Gabriele C. Hegerl¹ and Susan Solomon²

<link>

As the risks of climate change and the difficulty of effectively reducing greenhouse gas emissions become increasingly obvious, potential geoengineering solutions are widely discussed. For example, in a recent report, Blackstock et al. explore the feasibility, potential impact, and dangers of shortwave climate engineering, which aims to reduce the incoming solar radiation and thereby reduce climate warming (1). Proposed geoengineering solutions tend to be controversial among climate scientists and attract considerable media attention (2, 3). However, by focusing on limiting warming, the debate creates a false sense of certainty and downplays the impacts of geoengineering solutions.

¹ Grant Institute, Kings Buildings, West Mains Road, Edinburgh EH9 3JW, UK.
² National Oceanic and Atmospheric Administration, Earth System Research Laboratory, 325 Broadway R/CSD, Boulder, CO 80305–3337, USA.

ERL 2009: Focus on Climate Engineering

2009-09-02T06:20:17Z

Focus on Climate Engineering: Intentional Intervention in the Climate System

2009 Environ. Res. Lett. 4 045101

<link>

Geoengineering techniques for countering climate change have been receiving much press recently as a `Plan B' if a global deal to tackle climate change is not agreed at the COP15 negotiations in Copenhagen this December. However, the field is controversial as the methods may have unforeseen consequences, potentially making temperatures rise in some regions or reducing rainfall, and many aspects remain under-researched.

This focus issue of Environmental Research Letters is a collection of research articles, invited by David Keith, University of Calgary, and Ken Caldeira, Carnegie Institution, that present and evaluate different methods for engineering the Earth's climate. Not only do the letters in this issue highlight various methods of climate engineering but they also detail the arguments for and against climate engineering as a concept.

Further reading
Focus on Geoengineering at http://environmentalresearchweb.org/cws/subject/tag=geoengineering
IOP Conference Series: Earth and Environmental Science is an open-access proceedings service available at www.iop.org/EJ/journal/ees

Focus on Climate Engineering: Intentional Intervention in the Climate System Contents

Modification of cirrus clouds to reduce global warming
David L Mitchell and William Finnegan

Climate engineering and the risk of rapid climate change
Andrew Ross and H Damon Matthews

Researching geoengineering: should not or could not?
Martin Bunzl

Of mongooses and mitigation: ecological analogues to geoengineering
H Damon Matthews and Sarah E Turner

Toward ethical norms and institutions for climate engineering research
David R Morrow, Robert E Kopp and Michael Oppenheimer

On the possible use of geoengineering to moderate specific climate change impacts
Michael C MacCracken

The impact of geoengineering aerosols on stratospheric temperature and ozone
P Heckendorn, D Weisenstein, S Fueglistaler, B P Luo, E Rozanov, M Schraner, L W Thomason and T Peter

The fate of the Greenland Ice Sheet in a geoengineered, high CO₂ world
Peter J Irvine, Daniel J Lunt, Emma J Stone and Andy Ridgwell

Assessing the benefits of crop albedo bio-geoengineering
Joy S Singarayer, Andy Ridgwell and Peter Irvine

Can we control El Niño?
Douglas G MacMynowski

Geoengineering by cloud seeding: influence on sea ice and climate system
Philip J Rasch, John Latham and Chih-Chieh (Jack) Chen

Reference

Oschlies et al 2010: Climate engineering by artificial upwelling -- Channeling the sorcerer's apprentive

Glossary

Glossary

Robock et al 2010: A Test for Geoengineering?

Perspectives

Atmospheric Science:

A Test for Geoengineering?

Blackstock and Long 2010: The Politics of Geoengineering

Policy Forum

Climate Change:

The Politics of Geoengineering

Keith et al 2010: Research on sun block needed now

Opinion

Research on global sun block needed now

Abstract

Heckendorn et al 2009: The impact of geoengineering aerosols on stratospheric temperature and ozone

The impact of geoengineering aerosols on stratospheric temperature and ozone

The impact of geoengineering aerosols on stratospheric temperature and ozone

MacCracken 2009: On the possible use of geoengineering to moderate specific climate change impacts

On the possible use of geoengineering to moderate specific climate change impacts

Hangx and Spiers 2009: Coastal spreading of olivine to control atmospheric CO2 concentrations: A critical analysis of viability

Abstract

Hegerl and Solomon 2009: Climate Change - Risks of Climate Engineering

Perspectives

Climate Change:

Risks of Climate Engineering

ERL 2009: Focus on Climate Engineering

Focus on Climate Engineering: Intentional Intervention in the Climate System