Parallel Session 2.5: Rational Choice and Worst Case Scenarios

Wednesday, 11:00 - 12:30
01 I Großer Saal

If there is one moral argument that looms large against the prospects for Geoengineering it is the Precautionary Principle. In this session, the aim is to put this argument in a broader context in which all “facts” established via the scientific method are always open to falsification and hence cannot be known with certainty.



  • Martin Bunzl - SRM Risk and the problem of uncertainty
  • Ortwin Renn - Geoengineered Black Swans?
  • Douglas MacMartin - How uncertain is solar geoengineering?
  • David Keith - Solar geoengineering in a risk analysis framework

The session is chaired by Oliver Morton.

Convened by: 

Martin Bunzl

Rutgers University

Martin Bunzl is professor emeritus of Philosophy at Rutgers University and author of Uncertainty and the Philosophy of Climate Change published in 2015.


Douglas MacMartin

Cornell University
United States of America

Douglas MacMartin is in the Sibley School of Mechanical & Aerospace Engineering at Cornell University.  His research lies at the intersection between engineering feedback analysis and climate dynamics, with a primary focus on solar geoengineering – working to develop the knowledge base for society to make informed decisions.  In addition to applying engineering analysis to climate dynamics, he is also involved in control design for the Thirty Meter Telescope.  He received his Bachelors’ degree from the University of Toronto in 1987, and Ph.D. in Aeronautics and Astronautics from MIT in 1992; prior to joining Caltech in 2000, he led the active control research and development program at United Technologies Research Center.

David Keith

Harvard University
United States of America

David Keith has worked near the interface between climate science, energy technology, and public policy since ’91. He took first prize in Canada’s national physics prize exam, won MIT’s prize for excellence in experimental physics, and was one of TIME Magazine’s Heroes of the Environment. David is Professor of Applied Physics at the Harvard School of Engineering and Applied Sciences and Professor of Public Policy at the Harvard Kennedy School, and founder of Carbon Engineering, a Canadian company developing technology to capture CO2 from ambient air to make carbon-neutral hydrocarbon fuels. Best known for his work on the science, technology, and public policy of solar geoengineering, David led the development of Harvard’s Solar Geoengineering Research Program, a Harvard-wide interfaculty research initiative. His work has ranged from the climatic impacts of large-scale wind power to an early critique of the prospects for hydrogen fuel. David’s hardware engineering work includes the first interferometer for atoms, a high-accuracy infrared spectrometer for NASA’s ER-2, the development of Carbon Engineering’s air contactor and overall process design, and the development of a stratospheric propelled balloon experiment for solar geoengineering. David teaches science and technology policy, climate science, and solar geoengineering. He has reached students worldwide with an edX energy course. David is author of >200 academic publications with total citation count of >13,000. He has written for the public in op-eds and A Case for Climate Engineering. David splits his time between Cambridge, Massachusetts and Canmore, Alberta.

Ortwin Renn

Ortwin Renn
Institute for Advanced Sustainability Studies (IASS) Potsdam

Professor Renn is a Scientific Director at the Institute for Advanced Sustainability Studies (IASS) in Potsdam (Germany). Additionally, he continues to work with the Stuttgart Research Center for Interdisciplinary Risk and Innovation Studies at the University of Stuttgart (ZIRIUS) and directs the non-profit company DIALOGIK, a research institute for the investigation of communication and participation processes. Renn is Adjunct Professor for Integrated Risk Analysis at Stavanger University (Norway) and Affiliate Professor for Risk Governance at Beijing Normal University. His main research activities at the IASS focus on the role of systemic risks as threats to sustainable development, and the structures and processes for sustainable transformations in Germany and beyond.

Professor Renn has a PhD in social psychology from the University of Cologne. He is member of several boards, including the National Academy of Disaster Reduction and Emergency Management of the People’s Republic of China and the Governing Board of the German Academy of Science and Engineering (acatech). Renn has published more than 30 books and 250 articles, most notably the book Risk Governance (Earthscan: London, 2008).

Oliver Morton

The Economist
United Kingdom

Oliver Morton writes about scientific and technological change and their effects. He concentrates particularly on the understanding and imagining of planetary processes. 

He is a senior editor at The Economist, responsible for the magazine’s briefings and essays. He was previously Chief News and Features Editor at Nature and editor of Wired UK, and has contributed to a wide range of other publications. He writes on subjects from quantum physics to synthetic biology to moviemaking; his articles have been anthologised and won awards.

He is the author of three books: Mapping Mars: Science, Imagination and the Birth of a World (2002), which was shortlisted for the Guardian First Book Award; Eating the Sun: How Plants Power the Planet (2007), a book of the year in The Spectator and the Times Literary Supplement; and The Planet Remade: How Geoengineering Could Change the World (2015), longlisted for the Samuel Johnson Prize and shortlisted for the Royal Society Book Prize. In The Sunday Times Bryan Appleyard described it as “ambitious, enthralling and slightly strange”.

He is an honorary professor in Department of Science, Technology, Engineering and Public Policy at UCL and has a degree in the history and philosophy of science from Cambridge University. He lives with his wife in Greenwich, England, and Asteroid 10716 Olivermorton is named in his honour.