Geoengineering: A Primer

The term “Geoengineering”, the project prefers the term climate engineering, comprises activities specifically and deliberately designed to effect a change in the global climate with the aim of minimising or reversing anthropogenic climate change. The respective technologies are often classified into two distinct categories: so called Carbon Dioxide Removal (CDR), which sequester CO2 from (the exhaust of industrial plants or) the atmosphere and lock it in geological formations; and so called Solar Radiation Management (SRM) techniques, that change the planetary albedo, e.g. by injecting sulphate aerosols into the atmosphere.


The debate (so far)


Despite their profound (potential) importance to offset detrimental climate warming effects, the development, testing and implementing of these technologies has received little sustained attention and analysis from scholars, decision-makers, the business community and citizens. Since 2006, when Noble Price winner Paul Crutzen published an article on SRM techniques, which mimick volcano eruptions, the Geoengineering discourse has been confined to scholarly articles (cf. the Geoengineering Reader), a few substantial policy reports (Victor et al. 2009; Royal Society 2009, ETC Group 2009, Blackstock et al. 2009) and even fewer parliamentary deliberations (House of Commons 2010, USHOR Science and Technology Cmte. 2009, 2010a, b). Starting in spring 2010, the launch of an online- journal “Geoengineering Quarterly” and a couple of well-attended international conferences (Asilomar Conference on Climate Intervention Technologies; COP-15 Side events) have spread the discussion to mainstream media outlets (Die Zeit, New York Times, Time, Economist, Nature, Science, ARD German Television).


Two technologies: CDR and SRM


Drawing on the distinction between CDR and SRM technologies, the respective physical, political, legal, ethical and economical implications can be roughly broken down into two propositions: SRM technologies appear to be cheap, doable but politically, legally and ethically controversial because of their substantial detrimental distributional transboundary and trans-generational effects. CDR technologies appear to be more difficult and costly while the respective distributional implications may even garner cooperation among the actors concerned. In essence, SRM technologies imply a higher risk because they produce an unknown state of the planetary climate (high greenhouse gas concentration without corresponding climatic effects) whereas CDRs seek to either slow or reverse changes in the global carbon cycle, thereby reinstating a “known climatic condition”.


Global Governance


The Governance of Geoengineering, encompassing the development, testing and implementation phase of these as-of-yet unproven technologies, must address the diverse challenges outlined above (Morrow et al. 2009). It may import some of the regulatory frameworks of the climate change regime (among others the UNFCCC, Kyoto Protocol, UNCLOS, ENMOD, London Convention). These agreements contain important principles, e.g. “common but differentiated responsibility” and the prohibition of the military use of weather modification techniques, which will shape the debate as these norms also determine the breadth and depth of the challenges raised by climate warming. However, new arrangements may also have to be found. While existing norms address the problem to organize and sustain collective action some geoengineering techniques, SRM, raise the specter of unilateral action with profound trans-boundary effects.




Geoengineering strides numerous disciplines that address the relationship between incentives and actor behavior. One of the problematic incentives raised by GE may result in overconfidence: Premature trust in the ability of GE technologies to provide a public good without significant harm may undermine the resolve for CO2 abatement now. Another problematic incentive may lead to a coordination failure: The affordability of some GE measures may empower individual countries or even private actors to “go it alone” rather than engage in protracted multilateral negotiations over their use and possible detrimental effects.


Substituting geoengineering for CO2 mitigation may thus promise to be a cost-effective strategy if GE technologies pose a negligible (climate) or manageable risk in the future. Some observers stress that GE induces a classical “moral hazard” situation, i.e. the “tendency for the insurance against loss to reduce incentives to minimize the cost of loss” (Baker 1996). If states or even private actors were to deploy GE measures unilaterally, thus securing a private good, they could avoid multilateral coordination costs but impose additional costs on others. Furthermore, as GE methods promise to a varying degree to quickly stabilize negative climate effects and obfuscate negative transgenerational consequences, they may induce risk-prone behavior as common in moral-hazard situations.


To meet these challenges, interdisciplinary research, informed public debate and sustained international cooperation is in order. As current mitigation efforts stall and some small scale GE testing is already taking place, transnational deliberation and collaboration must move quickly and develop common principles (cf. Oxford principles on GE) for collective action.


Prof. Dr. Sebastian Harnisch, Heidelberg University, May 2010




Baker, Tom (1996): On the Genealogy of Moral Hazard, in: Texas Law Review 75:2, 236-292.

Blackstock, Jason J./Caldeira, Ken/ Eardley, Douglas M./Keith, David W./Patrinos, Aristides A.N./Schrag, Daniel P./Socolow, Robert H./Koonin, Steven, E. (2009): Climate Engineering Responses to Climate Emergencies (Novim, 2009), (accessed February 10, 2010).

Crutzen, Paul J. (2006): Albedo Enhancement by Stratospheric Sulfur Injections: A Contribution to Resolve a Policy Dilemma? In: Climatic Change 77: 3, 211-220.

ETC Group (2009): Retooling the Planet? Climate Chaos in the Geoengineering Age, (accessed February 12, 2010).

House of Commons Science and Technology Committee 2010: The Regulation of Geoengineering, Fifth Report of Session 2009–10, (accessed May 5, 2010).

Morrow, David et al. (2009): Toward ethical norms and institutions for climate engineering research, in: Environmental Research Letters, 1-8

Royal Society (2009) Geoengineering the Climate. Science, governance and uncertainty, (accessed February 10, 2010).

US House of Representatives Science and Technology Committee (2010b): Hearing III on Geoengineering: Domestic and International Research Governance, Washington, DC, (accessed May 5, 2010).

US House of Representatives Science and Technology Committee (2010a): Hearing II on Geoengineering: The Scientific Basis and Engineering Challenges, Washington, DC, (accessed May 5, 2010).

US House of Representatives Science and Technology Committee (2009): Hearing I on Geoengineering: Assessing the Implications of Large-Scale Climate Intervention, Washington, DC, (accessed May 5, 2010).

Victor, David G./Morgan, Granger M. /Apt, Jay/Steinbruner, John/Ricke, Kathrine (2009): The Geoengineering Option. A last resort against global warming? in: Foreign Affairs 88: 2, 64-67.





Bayrischer Rundfunk, Faszination Wissen 13.12. 2009: Geo-Engineering Gewagte Notoperationen am Patient Erde

Klimazeitreise 12, Presentation by Prof. Dr. Mark Lawrence,

Radio Broadcast at hr2 Wissenswert 28.02.2012: Geo-Engineering - der neue Größenwahn?










Responsible: M.Bräunche
Latest Revision: 2012-05-14