1. Introduction

Examples include Schellnhuber (2008), Ramanathan and Feng (2008), Smith et al. (2009), Bernauer and Schaffer (2010).

In line with much of the science-policy literature, I use the attribute ‘normative’ in a rather broad and inclusive sense: providing guidance for our choices (e.g., in public policy or in scientific knowledge production) in terms of what we should do or want to do – in contrast to a descriptive approach to what is actually the case. In this sense, ‘normative assumption’ is used synonymously with ‘value judgement’, a widespread but often misleading notion; normative assumptions are necessarily (yet sometimes only indirectly) related to ‘values’, i.e. to those aspects that we find particularly important and that we appreciate as guidance (in various fields of human life). Besides directly occurring as values, however, normative assumptions can be based on, or be identical with, for instance, virtues, principles, criteria, societal norms and (individual or group) interests (Biewald et al. 2015). More specifically, normative-ethical assumptions as the most discussed value judgements claim to provide well-reflected action guidance in terms of the good or the right that can be generalised (in contrast to, e.g., particular sectional interests in politics); as a discipline, philosophical ethics is identical with moral philosophy. ‘Epistemic’ or ‘cognitive value judgements’ (see Chap. 5) provide guidance for the particular field of knowledge production. Moreover, expertise is ‘policy-prescriptive’ if it, roughly spoken, provides or implies normative guidance (i.e., a preference) on disputable policy choices (see also Sect. 2.​1.​3). Chapter 5 provides a more detailed explanation and discussion of normative concepts; it also discusses the epistemological entanglement of normative and descriptive aspects.

See Kowarsch (2014) and Mitchell et al. (2006) for a more detailed explanation of scientific assessments.

For an overview of interesting philosophical questions regarding social sciences and climate change, see also Parker (2014).

This book does not investigate whether the WG III ARs sufficiently assessed all the available relevant literature and in an unbiased manner, nor whether there are errors in the economic details of the ARs. Instead, it focuses on some key philosophical aspects of the economics of climate change and how they were dealt with by the WG III.

According to Maasen and Weingart (2005), there were two waves of interdisciplinary publications on scientific policy advice. After the first wave in the 1960s, which focused on technocracy and the critique of it, there has been a second wave in recent years with a focus on democratic participation in scientific policy advice. Examples of seminal philosophical works on the role of science in policy include Habermas (1968), Brown (2009), Douglas (2009) and Kitcher (2001, 2011). Although there is a lot of literature on science-policy interactions, there is not much reflecting on scientific assessment-making in particular. Exceptions include, inter alia, Boehmer-Christiansen (1994a, b), Pinter (2002), Cash et al. (2003), Rayner (2003), Watson (2005), Mitchell et al. (2006), Farrell and Jäger (2006), NRC (2007), PBL (2008), UNEP and UNESCO (2009), Beck (2009), Rothman et al. (2009).

The high impact of such models and especially the need for a new model are explained, for example, by Beck (2009, p. 19; 2011), Pielke (2007), Brown (2009), Hulme (2009, pp. 102–10), Kitcher (2011, pp. 25f), Grunwald (2008, p. 285) and Jasanoff (e.g., 1990), but also by some bureaucrats and stakeholders.

There are a few works on the philosophy of the social sciences that also address some of the major aspects of social-science expertise in policy. See, e.g., Cartwright and Montuschi (2014) as well as Risjord (2014).

Among the exceptions is Brown (2012) who brings together Dewey’s philosophy of enquiry and current debates in philosophy of science. See also Chap.​ 6 for more discussion of the available literature.

The existing literature on the science-policy interface lacks a compelling justification and explanation of why and how alternative policy pathways can be explored. Most of the science-policy literature in the last two decades is about the sociology and history of scientific expertise in policy. These are undoubtedly valuable studies, but cannot replace the critical reflection on the philosophical issues.

See the literature discussed in Chaps. 7, 8 and 9.

“In response to some sustained criticism and a heightened level of public scrutiny of the Fourth Assessment Report, the United Nations and IPCC asked the InterAcademy Council (IAC) to assemble a committee to review the processes and procedures of the IPCC and make recommendations for change that would enhance the authoritative nature of the IPCC reports” (IAC 2010, p. v).

See particularly the different discussions in Nature 463 (Opinion, February 2010), pp. 730–32, and a couple of other articles in Nature 463 and 464. See also publications such as Skodvin (2000), Beck (2009, 2011), Hulme and Mahony (2010), Tol (2011), Pielke (2010), Watson (2010), Grundmann and Stehr (2011, Chap. 4), and the discussions, for instance, on the blogs http://​rogerpielkejr.​blogspot.​com/​, http://​wattsupwiththat.​com and http://​judithcurry.​com/​2011/​10/​06/​ipcc-discussion-thread/​. The governments’ discussions about IPCC reform can be found here: http://​www.​ipcc.​ch/​apps/​future/​ (all accessed 7 Jan 2015).

E.g., Victor (2015) mainly from the perspective of political sciences, and Carraro et al. (2015) mainly from an economics perspective.

See IPCC (2014, Preface).

Upcoming large-scale scientific assessment projects include, for instance, the envisaged assessments by the Intergovernmental Platform on Biodiversity and Ecosystem Services that explicitly follows the role model of the IPCC; the Sixth Global Environment Outlook by the United Nations Environment Programme; and the next UN Global Sustainable Development Report.