Institute of Philosophy

Institute of Philosophy

Climate change and Philosophy

Copyright: Iris Muoth


Joel Katzav (University of Queensland)

A possibilistic epistemology of climate modelling and its application to the cases of sea level rise and climate sensitivity

3 Nov. 2022, 14:15-16:00, Unitobler F014


It has been argued that possibilistic assessment of climate model output is preferable to probabilistic assessment (Stainforth et al. 2007; Betz 2010, 2015; Katzav 2014; Katzav et al. 2012 and 2021). I aim to articulate a variant of a possibilistic approach to such assessment. On my variant, the output of climate models should typically be assessed in light of two questions: is it fully epistemically possible? If the output is (fully) epistemically possible, how remote a possibility does it represent? Further, on my variant, if the output is judged to be epistemically possible, it should be taken to represent objective possibilities, specifically potentialities of the actual climate system. Having articulated my possibilistic approach, I apply it to two key issues in climate science, namely the potential contribution of marine ice cliff instability to sea level rise over the rest of the twenty-first century and climate sensitivity. Marine ice cliff instability (MICI) has been posited as a mechanism that might lead to substantially more sea level rise than had previously been projected (DeConto and Pollard 2016). I will suggest that existing assessment of the contribution of MICI to future sea level rise illustrates the strengths of my possibilistic approach and weaknesses of probabilistic approaches to assessing the output of climate models. I will also argue that the most recent Intergovernmental Panel on Climate Change assessment of climate sensitivity, especially its reliance on variety of evidence considerations to address the challenges of unexpectedly high climate sensitivity projections by state-of-the-art climate models, illustrate the strength of my possibilistic approach and the weakness of probabilistic approaches.



The Institute of Philosophy regularly offers courses which address questions of climate change from the perspective of philosophy of science and ethics.

In the spring semester 2023:

  • Seminar Philosophical Issues in Modelling Climate Change
    Lecturers: Vincent Lam, Stefan Brönnimann, Ralf Hand, Julie Jebeile

  • Proseminar Klimakrise: Philosophische Perspektiven auf ein zentrales Nachhaltigkeitsproblem
    Lecturers: Christoph Baumberger, Claus Beisbart, Georg Brun

  • Seminar: Moralische Verantwortung in der Klimakrise
    Lecturer: Matthias Rolffs

  • Research meetings of the Epistemology of Climate Change group (open to students, block course at 4 ECTS)
    Vincent Lam

    See programm of research meetings.


From 2023 on, there will be a Proseminar Philosophy and Climate Change (in German; by Christoph Baumberger, Claus Beisbart, Georg Brun) every spring semester.


Research: projects and interests

The institute collaborates with the Oeschger Centre for Climate Change Research.

Vincent Lam is leading the research project The Epistemology of Climate Change funded by the Swiss National Science Foundation and hosted at the Institute of Philosophy and at the Oeschger Centre for Climate Change Research. His group investigates the methodological and epistemic foundations of climate science and climate modelling using the tools of philosophy of science in view of addressing the climate challenge. The research group has also strong interests in broader philosophical issues related to the climate and environmental challenges. For research activities, seminars and more information on the project see

Julie Jebeile is working as a postdoc in the research project The Epistemology of Climate Change Her research interests include mathematical modelling, scientific expertise, as well as socioeconomic and ethical values in science with a special focus on climate science. Her contributions to the philosophy of scientific models and computer simulations and to the philosophy of climate science can be found here.

Mason Majszak is a Phd student working under the supervision of Prof. Dr. Vincent Lam within The Epistemology of Climate Change research project. He is currently writing his dissertation on the role of expert judgment in climate science, with further research interests including philosophy of science, probability theory, expert judgment, as well as scientific methodology.

Claus Beisbart is interested in the epistemology of climate models, the relationship between climate scientists and the public sphere and in foundational issues in climate ethics.

Recently completed projects: