The problem with incorporating climate engineering into climate models Robert Herrenbrück M.A. Departement of science, technology and society studies, Alpen-Adria Universität

Joeri Rogelj et al. 2016 in Nature

IPCC AR5 Table SPM 1.

IPCC AR5 SYR p. 81/ IPCC AR5 SPM p. 23 “Mitigation scenarios reaching about 450 ppm CO2-eq in 2100 […] typically involve temporary overshoot of atmospheric concentrations, as do many scenarios reaching about 500 ppm […] (Table SPM.1). Depending on the level of overshoot, overshoot scenarios typically rely on the availability and widespread deployment of bioenergy with carbon dioxide capture and storage (BECCS) and afforestation in the second half of the century. The availability and scale of these and other CDR technologies and methods are uncertain and CDR technologies are, to varying degrees, associated with challenges and risks.”

Lessons learned from the past 25 years Observation 1: Decades of climate negotiations show the limits of international cooperation. Without coherent structures there are no coherent policies. Observation 2: Climate models have always relied on successful international coordination and cooperation. Explanation: Just the way the science policy interface works? Question: Was optimism about mitigation baseless? Advocating mitigation has no downside. A failed mitigation effort is equivalent to no effort at all.

What is Climate Engineering (CE)?

Risks of Climate Engineering CE, especially SRM, contains risks for environment and climate. Risks need to be managed & monitored. Caution is necessary. Long-term global cooperation and coordination is required. “SRM governance involves restraining hasty unilateral action” (IPCC AR5 WGIII p. 1023) CE doesn’t make mitigation obsolete, it’s just “buys time”. Mitigation and CE need to be coordinated on a global scale.

Climate models repeat the same mistakes Climate models generally tended to overestimate the ability to coordinate and cooperate on a global scale. Climate engineering would require coordination to be safe. In mitigation scenarios baseless optimism is unproblematic. In CE scenarios it is potentially dangerous: CE can become more harmful then climate change. Trying and failing is more harmful then not even trying. To incorporate climate engineering into climate models is dangerous; at least until the technology is foolproof.

Further research Narrative Politics. How narratives shape the discourse. Agenticity (Michael Shermer). Overconfidence in human agency and political power. A bias caused by how narratives work? Framing. Changing the narrative? Responsibility in the science policy interface The ingenuity gap (Thomas Homer-Dixon)

References Geden, Oliver: Climate advisers must maintain integrity, Nature Vol. 521, p. 27-28 (7 May 2015). IPCC, 2014: Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, R.K. Pachauri and L.A. Meyer (eds.)]. IPCC, Geneva, Switzerland, 151 pp. Rogelji, Joeri: Paris Agreement climate proposals need a boost to keep warming well below 2 °C, Nature Vol. 534, p. 631–639 (30 June 2016). Oil Change International: The sky’s limit. Why the Paris climate goals require a managed decline of fossil fuel production, September 2016. Homer-Dixon, Thomas: The ingenuity gap, New York 2000. Shermer, Michael: The believing brain, New York 2013.