Research Seminar Spring 2022

2022-02-25 Why are Scientific Forecasts Regarding Climate Change Unable to Trigger its Mitigation?

Philippe Colo, University of Duisburg-Essen. [slides]

Unitobler, Lerchenweg 36, room F014, 10:15-12:00


We are laymen on most of the knowledge we claim to possess. Today’s science is too vast for a single individual to master it by himself. We say we know about the mechanism of climate change because of what we heard from experts of those fields. On such topics, our claimed knowledge relies much more on the confidence we have in these experts, than on the evidence we can directly access.

I explore the consequences of this epistemological dependence using game-theory to study expert-based climate knowledge. I consider a game of communication between a scientific authority and multiple greenhouse gas (GHG) emitters. I derive a negative result: in the only Nash equilibrium of this game, because of the difference of interest between parties, no information transmission can take place. In other words, in this context, confidence is broken between laymen and the authority. Even if the authority reports the truth, emitters ignore her advice and act solely upon their prior belief.

2022-03-18 Workshop: epistemic and methodological issues in climate science

Uni Mittelstrasse 43, room 324, 10:15–12:00 & 14:15-17:00.

– 10:15-12:00: Ted Shepherd, University of Reading

Bringing physical reasoning into statistical practice in climate‐change science. [slides]


The treatment of uncertainty in climate-change science is dominated by the far-reaching influence of the ‘frequentist’ tradition in statistics, which interprets uncertainty in terms of sampling statistics and emphasizes p-values and statistical significance. This is the normative standard in the journals where most climate-change science is published. Yet a sampling distribution is not always meaningful (there is only one planet Earth). Moreover, scientific statements about climate change are hypotheses, and the frequen- tist tradition has no way of expressing the uncertainty of a hypothesis. As a result, in climate-change science, there is generally a disconnect between physical reasoning and statistical practice. This paper explores how the frequentist statistical methods used in climate-change science can be embedded within the more general framework of prob- ability theory, which is based on very simple logical principles. In this way, the physical reasoning represented in scientific hypotheses, which underpins climate-change science, can be brought into statistical practice in a transparent and logically rigorous way. The principles are illustrated through three examples of controversial scientific topics: the alleged global warming hiatus, Arctic-midlatitude linkages, and extreme event attribu- tion. These examples show how the principles can be applied, in order to develop better scientific practice.

– 14:15-16:00: Marina Baldissera Pacchetti, University of Leeds

One or many? The logics of physical climate storylines.


An important purpose of physical climate science research is to accommodate the needs and lessons of societal risk assessments (Sutton 2019). The Physical Climate Storyline (PCS) approach can address some of these needs and lessons, as this approach borrows key insights from scenario (see e.g. Berkhout et al 2014) and narrative (see e.g. Coulter et al 2019) thinking and develops them in the context of climate change (e.g. see Hazeleger et al 2015, Shepherd 2016, Shepherd et al. 2018, Dessai et al. 2018, Shepherd 2019, Jack et al. (2021), Sillmann et al. 2021).

The PCS approach is increasingly recognized by the research community as a tool to produce and communicate decision relevant climate risk information. For example, the IPCC AR6 relies on the definition provided in Shepherd et al. (2018) to characterize PCS as “self-consistent and possible unfolding of a physical trajectory of the climate system, or a weather or climate event, on timescales from hours to multiple decades” (WG1, In this same report, Box 10.20 mentions PCS as tools for different purposes, e.g. for the exploration of low likelihood, high impact events (IPCC, WG1, §4.8), of cross-scale interactions for the purpose of informing adaptation (§, as a particular approach including pseudo-global warming studies (§, as an alternative approach to event attribution studies (§11.2.4), as information distillation exercises (§10.5.3), or as providing climate information that is integrated with socio-economic information and delivered in the form of narratives through climate services (Cross-Chapter Box 12.2).

While PCS is generally understood as a single approach, different methodologies are applied associated with the aims and purposes of the approach. To unpack this diversity of detail, this article gives an overview of the key methodological practices and assumptions of the PCS approach (the “logics”). We analyze physical climate storylines as both a product and a process (for a similar analysis of scientific practice in the context of climate research see Hulme and Dessai 2008) and recognize that (i) those who build the storylines and (ii) the purpose for which these storylines are built influence key features of the methodology (process) and hence key features of the storyline (product).

We will start our analysis from the literature in the IPCC AR6 WG1 that is classified as producing physical climate storylines (PCS). Selecting papers from IPCC assumes that the IPCC provides a comprehensive assessment of the state-of-the-art in climate change research, where climate scientists can individuate a methodology as being part of a more general approach. Moreover, inclusion in an IPCC report implies a certain level of acceptance by the scientific community, far more so than individual journal publications. The heterogeneity of the storyline approach (and the fact that many papers follow the storyline “logic” without explicitly identifying the underlying rationale as a “storyline”) motivates this choice and substantiates the assumption that the IPCC can provide a better overview than a systematic literature search. Consequently, this article provides a critical overview of key sub-methodologies associated with the concept of physical climate storylines rather than an overview of the literature at large. Compared to Shepherd et al. (2018), which was the first systematic synthesis of the PCS approach in the literature, we can provide a more extensive overview of the various PCS methodologies and their acceptance by the wider community, viewed through the lens of the IPCC AR6 WG1 report.

After a short introduction that puts PCS in a broader context of generating decision relevant information about future climate, we describe key characteristics of different approaches to developing PCS and organize the literature according to (1) key methodological choices (i.e. how the unfolding of the physical trajectory is constructed) found in the individual papers, (2) the way that the temporal element is included in the construction of PCS and (3) who builds these storylines for whom. We then discuss in more detail how value judgements (see, e.g. Intemann 2015, Pulkkinen et al. 2022) are incorporated into PCS. We conclude the article by suggesting where the PCS approach can improve and further mature.

– 16:00-17:00 Round-table

The relevance of philosophy of science for climate science

2022-04-01 Uncertainty attitudes as values in science

Uni Mittelstrasse 43, room 324, 14:15–16:00.

Joe Roussos, Institute for Future Studies (Stockholm). [slides]

Abstract This paper aims to expand what counts as a “value” in science. The wide-ranging discussion of values in science has thus far focused primarily on a what I will call first-order values: moral, political, and social values which are used to evaluate outcomes. My focus is on uncertainty attitudes, the best known of which is risk aversion. These, I claim, encode values such as the value of certainty, the disvalue of facing negative possibilities, and the value of having a chance. Such attitudes influence the conduct of science: two scientists with different uncertainty attitudes will make different decisions, even if they have identical evidence, beliefs, and first-order values—including an agreement on the value of each kind of inferential error. I illustrate this with simple stylised examples. Then, I argue that these attitudes are not plausibly epistemic values. Next, I consider what issues they raise for the norms of science. I find that many classic “values in science” questions reoccur. I close with a discussion of whether a seemingly simple “fix”—demanding that scientists be risk neutral—resolves these concerns. I argue that it does not.


Greg Lusk, Durham University.

– 10:15-12:00: The Aims and Purposes of Extreme Event Attribution

Uni Mittelstrasse 43, room 220.

Abstract Extreme event attribution attempts to demonstrate that human actions have had an influence on the frequency with which a kind of an extreme event occurs, or on the magnitude of a particular extreme event. While extreme event attribution can enhance science’s understanding of the Earth’s climate, scientists and other researchers have proposed that extreme event attribution should have a role in climate-related decision making. How should we judge such proposals? This talk investigates the criteria upon which we should evaluate the use of extreme event attribution. Specifically, it will explore how social aims and purposes should impact the way that we assess the usefulness of investigations like extreme event attribution and show how we might better align our scientific tools with our social ends.

– 14:15-16:00: Towards a Political Philosophy of (Climate Change) Science

Uni Mittelstrasse 43, room 324.

Abstract A common assumption about science is that – at least in its core internal aspects – it should be free of non-epistemic (or “social”) values. There are two justifications for this “value free ideal.” The first is that science’s job is to find truths about the world, and our social values are irrelevant to that project. The second is that – at least in a democracy – scientists inserting social values into science would be illegitimate on political grounds. This talk investigates this second, less examined, justification. I show that there is no incompatibility between value-laden science and democracy. However, the standards necessary to ensure compatibility might be rather high, and this has implications for how processes like knowledge co-production work in the context of climate science and climate services. Working from climate services as an example, I explore how the high standard of democracy might be met through the distribution of legitimizing practices across different social moments.

2022-06-03 Climate Adaptation, Urgency and the Limits of Justice

Uni Mittelstrasse 43, room 324, 14:15–16:00.

Ivo Wallimann-Helmer, University of Fribourg.

Abstract For effective climate adaptation scientific understanding of extreme weather events and the probabilities of their occurrence is necessary. This paper explores various contexts of climate adaptation and argues that these contexts change how the fair differentiations of responsibilities must be justified. Most crucially it argues that for reasons of justice and efficiency it is not always those contributing most to climate change that are under special duty.