Expert Advice and Global Environmental Governance: Institutional and Epistemic Challenges for Assessment Bodies

Abstract

The global community remains significantly off track in achieving the United Nations Sustainable Development Goals (SDGs), prompting calls for not only stronger political commitments but also more effective and credible expert guidance. This paper contributes to this discourse by examining a critical form of global environmental expertise: the conduct of global environmental assessments. Such expertise has become a foundational component of the institutional architecture underpinning global sustainability governance. Focusing on the Intergovernmental Panel on Climate Change (IPCC), one of the most prominent and widely recognized international expert bodies, this study examines the challenges that researchers face when synthesizing research findings and making them policy-relevant within the IPCC’s assessment work. The empirical material consists of an interview study (N = 18) conducted with experts involved in the IPCC, from its first assessment (1990) to the most recent one (2023). The data were analyzed thematically using NVivo. The analysis reveals four key internal challenges that the IPCC must address to enhance its advisory capacity: epistemic hierarchies, leadership and management dynamics, the complexities of formulating recommendations, and inequities in recognition and reward systems. By identifying and analyzing these challenges, the paper contributes to ongoing discussions about the IPCC’s future development and offers broader insights into the evolving role of scientific expertise in global environmental governance.

1. Introduction: Towards a Transformed Scientific Expertise?

As society has become more complex, scientific expertise has become increasingly important in governing and regulating societies [1,2,3]. This expertise faces the dual challenge of managing scientific authority while ensuring policy relevance, a task that becomes particularly demanding when decisions have far-reaching societal implications [4]. These challenges are compounded scientifically by disciplinary fragmentation within science [5] and political polarization [6], raising critical questions about how to render scientific knowledge actionable—capable of informing decisions and guiding interventions [7].

In the context of global environmental challenges, the development of science-based advice is especially complex. For example, as climate issues have gained increased attention, relevant knowledge has emerged from a broader range of disciplines and research areas, making the task of synthesizing climate research particularly challenging. As a governmental representative in the IPCC puts it: “there is an exponentially growing body of scientific research on climate change. The effort and challenges to even begin a full assessment of this flood are enormous.” [8] (p. 7). The IPCC’s most recent assessment report (AR6) reviewed more than 66,000 articles and the final versions of its three assessment reports spans more than 8000 pages. In addition, the international community increasingly calls for solution-oriented assessments that not only diagnose problems but also identify and support actionable pathways for change [9]. This further complicates assessment work, which must present actionable options to be politically relevant while maintaining scientific credibility [10,11].

The growing complexity of expert advice has prompted numerous proposals to reform the science–policy interface to enable more science-informed decision-making. These proposals often focus on intergovernmental panels conducting global environmental assessments (GEAs)—comprehensive syntheses of knowledge within specific policy domains intended for decision-makers [12]. Suggestions range from internal transformations within science [13] to strategies for improving engagement with users, including restaging and reframing issues [14] and redesigning institutional arrangements at the science–policy boundary [1,15,16]. However, these discussions frequently overlook the lived experiences of the experts themselves. Regardless of institutional design, it is individual researchers—typically affiliated with universities or research institutes—who voluntarily commit time and effort to conducting GEAs.

This paper investigates the challenges faced by intergovernmental expert organizations conducting GEAs, with a particular focus on the IPCC. It does so by exploring how participating scientists perceive and evaluate epistemic and institutional challenges of being experts. While there is considerable debate regarding the types of expertise required to support transformative change [2,3,17], comparatively little attention has been paid to the practical and institutional conditions under which experts operate. Given the demanding nature of assessment work—particularly in terms of time commitment [18]—it is crucial to understand the motivations and constraints that shape expert participation. Expert organizations must continuously recruit researchers willing to contribute without financial compensation; failure to do so risks undermining both the quality and legitimacy of their work.

The IPCC is selected as the focal case due to its prominence, institutional maturity, and well-known status as an international expert organization [19]. It has developed a unique position in providing expert advice and has been highly successful in influencing the international climate policy agenda. It is widely regarded as a model—or at least a reference point—for other expert organizations [20]. At the same time, the IPCC possesses unique characteristics and should not be viewed as a universal blueprint for expert panel design [21,22]. Nonetheless, the experiences of individual experts within the IPCC provide valuable insights for the development and reform of other expert organizations.

The paper is divided into six sections, including this introduction. The next section conceptualizes a specific form of expertise: that which conducts broad knowledge assessments involving experts from very different disciplinary fields. The third section presents the material and method: an interview study with researchers involved in the IPCC. The fourth section provides a systematic account of the researchers’ experiences and reflections, including their views on the opportunities and problems encountered in their expert work. Based on this analysis, the fifth section draws more general conclusions, highlighting four key challenges. Finally, the sixth section returns to the broader question of strengthening the role of science in policymaking, emphasizing the need to enhance not only the design of the science–policy interface but also the internal robustness of scientific expertise, by discussing the conditions, incentives and motivations for scientists to devote time to this work.

2. Expertise: Science for Policy

There is a growing need to synthesize and condense specialized scientific knowledge to make it relevant, understandable, and usable by decision-makers. In response, intergovernmental expert organizations have been established across various environmental fields, tasked with conducting GEAs [9,12,14]. These organizations assess the state of knowledge within specific policy areas and communicate their findings to policymakers, thereby supporting the development of science-informed international agreements. Today, these intergovernmental panels are integral to the architecture of global sustainability governance [23,24].

Producing such assessments requires an epistemic infrastructure that facilitates collaborative work, along with a shared epistemic culture that provides guidance on how to utilize this infrastructure. It also depends on trained members who have acquired the necessary skills to carry out the work [25,26]. Assessment work involves rules and methodologies for classifying and ordering phenomena, selecting, interpreting, and evaluating empirical material (scientific articles), addressing uncertainties, and formulating conclusions that are both scientifically valid and policy-relevant [12].

Unlike traditional research, which involves generating knowledge within a specialized field, GEAs focus on synthesizing existing knowledge across disciplines, often in areas where assessors lack the expertise to produce original research [24]. This distinction is captured in Science and Technology Studies through the concepts of contributory and interactional expertise [27] (p. 13–44). Contributory expertise refers to the ability to produce knowledge within a field, while interactional expertise involves mastering the language of a field without the capacity to generate new knowledge.

This poses a significant challenge: experts may be tasked with evaluating knowledge they are not formally trained to produce or critically assess [12]. To maintain credibility, expert organization must ensure consistency in assessments across diverse disciplinary backgrounds. This requires developing and maintaining an epistemic infrastructure and culture that guide the individual experts in their assessment work [28].

GEAs are thus engaged in knowledge production that transcends disciplinary boundaries. Their infrastructure, culture, and practices are designed for interactional expertise aimed at evaluating and synthesizing established knowledge. At the same time, their epistemic authority derives from their connection to science, specifically, the contributory expertise of their members. Consequently, GEAs must cultivate expertise that is recognized and trusted both by scientific peers (internal credibility) and by those seeking expert advice (external credibility) [4,27]. This dual requirement underscores the importance of expert socialization: researchers must learn to assess knowledge beyond their disciplinary and methodological training [29].

3. Materials and Methods

3.1. The IPCC

The IPCC is the UN body responsible for assessing the science of climate change. Established in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP), its primary goal is to provide governments with scientific input to inform climate policies [30]. Over time, it has become the most authoritative source of climate knowledge, involving scientists from diverse disciplines and regions, and serving as a model for other expert environmental bodies [19]. Since its inception in 1988, the IPCC has produced six assessments, the latest completed in 2023. At its meeting in 2024 (IPCC-60), it launched the next assessment cycle (AR7).

The IPCC’s organizational structure has remained stable, comprising three working groups that address different aspects of climate change: the physical system (WG1), climate impacts and adaptation (WG2), and mitigating strategies (WG3). A defining feature of the IPCC is its mandated to be policy-relevant but not policy-prescriptive [31]. According to its governing principles, “IPCC reports should be neutral with respect to policy, although they may need to deal objectively with scientific, technical and socio-economic factors relevant to the application of particular policies.” [30] (§2). To uphold this principle, the IPCC has developed a rigorous procedure for assessing scientific knowledge [32,33].

Like many boundary organizations operating at the intersection of policy and science, the IPCC must navigate diverse and often conflicting external demands, while comprising individuals with different values and areas of expertise [12]. As the scope of climate change has broadened, the range of disciplines involved in the assessment has expanded accordingly [34]. This has intensified the internal challenge of conducting assessments in a coherent and consistent manner. In response, the IPCC has gradually developed general guidelines to address these complexities. One notable example is its standardized approach to risk and uncertainty, which includes a common language for expressing uncertainty and confidence as well as a consistent terminology across working groups [35,36]. These measures aim to enhance clarity and transparency in assessments and in the communication surrounding them.

However, having formalized guidelines and procedures is one thing; implementing them effectively is another. It is therefore important not to limit analysis to the organization’s front stage—what it communicates externally (e.g., on its website, or official documents) and promotes internally (e.g., assessment guidelines). Backstage, in the internal assessment work and day-to-day operations, there may be a wide range of perspectives on how to assess knowledge, formulate recommendations, and delineate the boundary between policy-relevant and policy-prescriptive advice.

Considering the IPCC’s internal heterogeneity, which encompasses scientists from a wide range of disciplinary backgrounds and epistemological orientations, it is reasonable to posit the existence of a broad spectrum of perspectives on how to make scientific knowledge relevant to policy while safeguarding its epistemic integrity. Therefore, examining the views of IPCC experts on the conditions under which science can inform climate policy without compromising its credibility is of particular scholarly interest.

3.2. The Interview Study

The selection strategy for the interview study was designed to capture a broad range of experience among experts holding key roles in the IPCC’s assessment work. This includes both authors (Coordinating Lead Authors, Lead Authors) and individuals in leadership or coordination roles (Co-chairs, Technical Support Units). The composition of participants was intentionally structured to reflect the overall diversity of the IPCC experts, ensuring representation across all three working groups, various geographical regions, and different genders.

An additional selection criterion was that the participants should currently engaged with, or have recently worked within, the IPCC, thereby ensuring familiarity with its current operational practices. Many participants had also contributed to previous assessments cycles, allowing for reflections on historical changes in IPCC assessment practices and their evaluation of these developments. Selected interviewees were drawn from a wide range of central positions within the IPCC, ensuring a comprehensive perspective on the assessment process.

Interviews were conducted digitally between March and November 2020, each lasting between 60 and 90 min. Prior to each interview, participants were informed of the purpose of the study and provided written consent.

Disciplinary and representational backgrounds significantly shape individual experiences within the IPCC. Accordingly, the study was designed to ensure a diversity in terms of disciplinary, gender, and regional representation. The final composition of the interview sample is as follows:

• Disciplinary composition: 14 natural scientists—3 social scientists—1 person with non-scientific competence (administrative officer)
• Gender composition: 12 males—6 females
• Regional composition: 7 Europe, 7 North America, 2 Asia, 1 Africa, and 1 South America.

The gender distribution of the interview sample is comparable to that of the most recent IPCC assessment cycle (AR6), in which 66% of experts were male and 34% were female. However, this study has lower regional representation (in AR6, 35% of the experts were from the Global South). The IPCC does not systematically report data on disciplinary diversity.

It is important to emphasize that the primary objective of this study is to identify the challenges the experts encounter in their assessment work, rather than to analyze these challenges through the lens of social determinants. Due to the limited sample size, the study design does not support systematic comparisons across subgroups.

Because many of the experts have been involved in multiple assessment cycles and held various roles, their collective experience spans a wide range of responsibilities within the IPCC. The overall experience of the interviewees is as follows (

Table 1. Composition of the interview study.

Roles/Positions	Contributions
National Focal Points	2
Secretariat	1
Co-chair	2
Coordinating Lead Author	9
Lead/Review Author	20
Technical Support Unit	<3
Working Groups
Working Group I	12
Working Group II	17
Working Group III	5
Assessment Reports
AR6	13
AR5	7
AR4	4
AR3	6
AR2	5
AR1	2

):

Thus, although the interview study includes only 18 experts, they represent a considerable breadth and depth of experience within the IPCC.

The interview study was semi-structured around six topics:

• Involvement, motivation, and implications for your academic career.
• Similarities and differences between your work as an IPCC expert and your work at a university/research institute.
• Interdisciplinarity: why and how has it been conducted in the assessment work? Your evaluation of it—hinders and opportunities in collaboration with other disciplines and research traditions.
• Opportunities and challenges you find in the assessment work.
• Future challenges for the IPCC and what competences are needed to cope with them.
• Science for policy: what role does the IPCC play in climate policies, and what role should it play? What are the challenges for the IPCC in its effort to be policy-relevant?

NVivo 12 Pro qualitative data analysis software was used to conduct a contextualized thematic analysis [37] (p. 578–581). The interview data were analyzed thematically, guided by the original interview protocol and interview guide to extract themes. Of the eight themes constructed (comprising 36 subcategories), four were deemed relevant for this paper: “motivation,” “expert practices,” “disciplinary contribution,” and “interdisciplinarity.”

The analysis did not aim to identify and compare differences based on gender, geographical region, or working group, but rather to identify and interpret core experiences and perspectives associated with serving as an IPCC expert. To maintain the contextual integrity of participant quotations, the working group affiliation of each expert is disclosed. This is important, as the working groups differ in their different disciplinary composition and thematic orientation. However, to uphold participant anonymity, additional identifying information—such as disciplinary background, assessment cycle, or country—is deliberately excluded.

4. Results

In general, the interviewees described their experiences in predominantly positive terms. This does not imply any absence of critique regarding the IPCC’s operational practice; rather it reflects a shared perception that the organization provides a meaningful framework, serves an important function, and offers a valuable platform for scientific engagement. All participants viewed their involvement in the IPCC as both important and meaningful.

The thematic analysis of the interview material revealed several motivations for participating in the IPCC, along with perceived benefits and challenges (

Table 2. Benefits and challenges of being an IPCC expert.

Benefits

• Influence policy

• Learning experience

• Professionally rewarding

Challenges

• Managing different disciplines

• Professionally unrewarding

). The most frequently cited benefits were: (i) the opportunity to influence policy, (ii) access to valuable learning experiences, and (iii) professionally rewarding. However, interviewees also reported notable challenges associated with their involvement. The most commonly mentioned were: (i) difficulties in managing diverse forms of scientific knowledge, and (ii) limited professional recognition and reward.

4.1. Policy Influence

All interviewees cited the opportunity to influence policymaking as the primary motivation for participating in the IPCC. They expressed a strong commitment to making climate science relevant to policymakers and viewed the IPCC as a key instrument in this endeavor. Within this broad commitment, several political functions of the IPCC were highlighted, the most frequently mentioned being: (i) removing scientific discussion from political negotiations, (ii) fostering global consensus, (iii) enhancing scientific authority, and (iv) guiding policy action.

Some respondents noted that the IPCC helps to remove scientific or quasi-scientific debates from climate negotiations, thereby allowing policymakers to focus on the negotiations and policy development. As one participant explained: “the effect of IPCC is to take arguments about science off the table at the climate negotiations and save everybody a lot of time.” (#10, male, WG1, WG2).

Several respondents emphasized that the IPCC makes it difficult for policymakers to challenge scientifically established positions. For example, one respondent noted that science has rendered the concepts of “loss and damage” politically viable, despite discomfort among some politicians (#5, female, WG1). This statement is based on the fact that loss and damage resulting from climate change has been a key political issue in international climate negotiations, particularly for Small Island Developing States (SIDS) and Least Developed Countries (LDCs). It has been a long process to get it included in the IPCC assessments, but in the most recent one (AR6), it was assessed by Working Group 2, which argued strongly for addressing loss and damage.

Some respondents stressed the IPCC’s successful role in building global scientific consensus. This consensus is seen as crucial not only for international negotiations, but also for shaping domestic policy debates. The assessment process also provides experts with insight into which climate issues are politically sensitive and which are politically expedient, as well as what the global scientific community is saying about various climate issues.

While many underscored the importance of presenting scientific facts, most also emphasized the need to offer guidance on desirable and feasible responses. They observed that the IPCC has evolved to become more multidisciplinary and more outward-looking, increasingly attuned to the needs of society.

4.2. Learning Opportunities

Although the desire to influence policy was a primary motivation, nearly all interviewees highlighted the significant learning opportunities afforded by their involvement in the IPCC—opportunities not typically available within their home institutions. These experiences fall into three main categories: (i) interdisciplinarity, (ii) communication, (iii) cultural understanding.

Interdisciplinarity was described as both challenging and enriching. Experts noted the difficulty of navigating unfamiliar disciplinary frameworks and the need for humility when stepping outside their areas of expertise. Yet many viewed this as a unique and valuable opportunity for interdisciplinary collaboration. As one respondent put it: “It has really taken me several steps way beyond what my disciplinary boundaries were. So, in that sense, that is why we hold onto this, because this is an opportunity that we would never get in a conventional academic career.” (#16, female, WG3).

Another respondent called it “an incredible experiment” to bring together people with very different backgrounds and perspectives to work together” (#5, female, WG1). Several respondents cited the work on the Special report on Global Warming of 1.5 degrees as a particularly valuable, highlighting the close collaboration across working groups and disciplines required to produce the report.

Communication both within and beyond the scientific community was another key are of learning. Internally, experts grappled with disciplinary language differences. As one respondent noted it: “Whenever you get people from different disciplines together, it can take quite a long time to find out whether you are speaking a common language in terms of, when you refer to something, do you mean the same thing by the same words? And quite often the answer is no. And that is one of the fun things about the IPCC report, that experience.” (#7, male, WG3). Externally, the challenge lay in translating complex science into policy-relevant messages: As one participant remarked: “All of us are scientists not policymakers; it is very difficult to get a sense of how, what assessment message we can have” (#4, male, WG2).

Cultural understanding was the third area highlighted. Some respondents viewed the challenge as less disciplinary, primarily involving cultural belonging, gender dynamics, communication styles, and differing academic norms. One respondent emphasized that a key benefit of IPCC involvement is that it “bring[s] different people, different cultures, different disciplines together, in that you can have that conversation, or you can try and have that conversation.” (#7, male, WG3).

4.3. Professionally Rewarding

Several of the interviewees emphasized that participating in the IPCC has been highly beneficial to their scientific careers in three different ways. First, IPCC involvement is widely regarded within the scientific community as a marker of excellence. For some research fields, inclusion in assessment reports is particularly valued, given the IPCC’s status as an authoritative source. As one respondent put it: “if you work in the environmental science, the IPCC is the top platform” (#4, male, WG2).

Second, participation broadens researchers’ perspectives and enhances the visibility and demand for their disciplinary expertise.

Third, the experience provided indirect benefits through the acquisition of transferable skills—particularly interdisciplinary collaboration and team management—that are instrumental for academic career development.

4.4. Managing Diverse Forms of Scientific Knowledge

Producing GEAs necessarily involves collaboration across diverse disciplines and research traditions. As noted earlier, this interdisciplinary engagement offers unique learning opportunities. However, several respondents also identified it as a source of significant challenges.

A commonly cited issue was the difficulty navigating different disciplinary languages. As one respondent observed: “You have the paleontologists, observationalists, statisticians, dynamicists, modelers, all of these people, and they are all completely different communities that don’t speak the same language.” (#5, female, WG1).

A more fundamental concern raised by several participants related to the integration of diverse forms of scientific knowledge. These differences span disciplinary boundaries, epistemological orientations, and methodological approaches—particularly between quantitative modeling and qualitative or context-sensitive research. As one respondent noted: “there are literally people who basically say if you are not quantifying things, it is not scientific analysis and assessment, and therefore, policymakers aren’t going to pay attention to it.” (#11, male, WG2). Related to this, some respondents expressed frustration that rich, context-specific case studies are often marginalized in the assessment process. Although such research is essential for understanding localized climate impacts and the feasibility of adaptation strategies, it is frequently sidelined due to its perceived incompatibility with dominant assessment frameworks.

Organizational factors were also seen as exacerbating interdisciplinary tensions. The disciplinary composition of the IPCC’s working groups was viewed by some as reinforcing epistemic divides. A recurrent concern was the perceived dominance of Working Group 1, which influences the work of Working Groups 2 and 3. As one participant explained: “Anybody who spends any time thinking about risk assessment and management would say that it’s a backwards model, because it’s Working Group 2 that’s supposed to define the risks, and Working Group 1 should be helping assess the likelihood of exceeding thresholds and encountering those risks.” (#11, male, WG2).

4.5. Professionally Unrewarding

A second concern raised by some interviewees is that serving as an IPCC expert is not consistently professionally rewarding. While some participants reported career benefits (see above Section 4.3), others emphasized that the role offers limited academic recognition and detracts significantly from time available for research. As one senior researcher noted: “I would have a real hesitation in recommending involvement to junior scholars because it definitely takes a hit on your ability to work on your own stuff.” (#17, female, Special report). The professional value of IPCC involvement was described as highly context-dependent. In some research environments, it is regarded as a prestigious credential; in others, it is perceived as a diversion from core academic responsibilities, undertaken at the expense of research productivity.

5. Discussion

The analysis reveals that the opportunities and challenges faced by the IPCC experts are situated at both individual and institutional levels. While the IPCC constitutes a bounded space for knowledge production, it is populated by—and dependent on—individual researchers whose primary professional affiliations lie outside the organization, typically within universities and research institutes [18]. This dual positioning means that even though the IPCC has developed its own epistemic infrastructure and culture, it remains influenced by the norms and practices of the broader academic landscape. As noted in the analysis, interviewees evaluated their involvement in the IPCC positively, a finding consistent with research on expert organizations conducting GEAs [24]. At the same time, they identified several obstacles encountered in their expert practices. Four of these obstacles merit particular attention: transcending epistemic hierarchies, the role of leadership and management, the challenge of providing recommendations, and the unequal academic reward system.

5.1. Transcending Epistemic Hierarchies

The study shows that the experts involved in the assessment work cannot rely solely on their primary disciplinary competence (i.e., contributory expertise). They must also develop interactional expertise—an understanding of other fields in which they are not active, often without the ability to critically evaluate these forms of knowledge and thus relying on the assessment colleagues. Acquiring international expertise requires humility and openness toward disciplines and methodologies beyond one’s own.

A particular challenge, sometimes explicitly stated and other times implicit in the respondents’ accounts, is the existence of epistemic hierarchies—the different valuation of different types of scientific knowledge. These hierarchies are not merely the result of individual attitudes but are reinforced by the institutional design of the IPCC [35]. The central role of aggregation, upscaling, and modeling in the assessment work means that certain types of knowledge are more easily integrated into the assessments [38]. In contrast, context-sensitive knowledge, such as qualitative case studies, is more difficult to synthesize and often marginalized [28].

This dynamic is evident in the IPCC’s pathway approach [39], which emphasizes technological measures and future innovations to limit global warming [4,40,41]. However, these scenarios are often presented without sufficient engagement with research on the social implications and political feasibility of proposed measures and pathways [10].

This challenge is further compounded by the disciplinary organization of the IPCC’s working groups: WG1 is predominantly composed of natural scientists, WG2 includes many social scientists, and WG3 features a strong presence of technologists. Yet, it is overly simplistic to attribute the problem solely to disciplinary composition. A more productive framing is to view it as a problem of epistemic hubris—a lack of awareness of the normative commitments and epistemological assumptions embedded in one’s owns research tradition [42].

Addressing this issue requires epistemic humility—a more reflexive and respectful approach to other scientific disciplines and research traditions. However, individual reflection is not sufficient. What is needed is institutional reflexivity [43]—a critical examination by the organization itself of its epistemic infrastructure and culture. This includes scrutinizing the underlying conception of science that informs its epistemic practices and the message it conveys to participating experts.

5.2. The Importance of Leadership and Management

The existence of epistemic hierarchies points to another challenge: leadership and management. The IPCC operates within a formal and rigorous structure for conducting assessments—including procedures for expert selection, literature review, and the handling of knowledge uncertainties [36]. Yet, as both this study and previous research have shown [32], individual experts within chapter teams retain considerable autonomy in expressing their views. This autonomy requires the chapter team leaders to manage situations where disciplinary traditions, gender, or seniority may lead some experts to devalue the contributions of others—an issue some interviewees had experienced.

Leadership styles, particularly those of the Coordinating Lead Authors, have also been found to play a crucial role in fostering inclusive participation, especially for experts from the Global South [44].

While leadership and management skills are not unfamiliar to scientists, they are essential for the management of large research programs or interdisciplinary research centers [45,46]. However, the demands of managing an expert organization differ significantly from those of traditional research. GEAs involve broader knowledge domains (e.g., climate change), more heterogeneous disciplines, distinct activities (knowledge assessment rather than production), and different audiences (policymakers rather than academic peers). Moreover, in expert organizations like the IPCC, senior scientists may find themselves in a junior role, with less experienced researchers possessing greater familiarity with assessment processes [29]. This inversion can be challenging, particularly when compounded by factors such as gender or disciplinary affiliation [47,48]. For GEAs to function effectively, individual experts must develop collaborative competencies, and coordinating lead authors and lead authors must be equipped to guide diverse chapter teams through complex assessment tasks.

5.3. The Problem of Unequal Reward Systems

The IPCC brings together people from diverse disciplines, regions and backgrounds, all united by a shared desire to influence society by communicating science to policymakers. However, the incentive structures that govern their participation vary widely. For some, involvement in the IPCC yields significant professional recognition and career benefits—both personally and for their affiliated institutions. For others, it is an unrecognized activity that detracts from time available for research and other academically rewarding tasks. Nevertheless, many continue to contribute out of a commitment to influence climate policy.

While some studies suggest that participation in GEAs is generally professionally rewarding—offering visibility, networking opportunities and a comprehensive overview of a scientific field [24]—others highlight the prevalence of invisible and unrewarded work. Activities essential to producing assessment reports, often fall under the category “academic housekeeping” and receive little formal recognition [18].

In addition to differences in how specific tasks are valued, disciplinary differences also shape perceptions of academic merit. Participation in GEAs tends to carry lower merit value in the social sciences and humanities [49,50]. These differences make it rational for some researchers to decline participation, even if they are otherwise motivated to contribute. Furthermore, experts from the Global South often face structural barriers, including limited institutional support and financial constraints, which make unpaid work for the IPCC particularly difficult [44].

A particular challenge for the IPCC—and for expert organizations more broadly, is that incentive structures lie largely outside their sphere of influence. The evolving concept of “academic citizenship” offers a potential avenue for addressing this issue, by recognizing that activities beyond research and teaching—such as science–society interaction—are central to the mission of universities [51,52].

5.4. The Challenge of Making Recommendations for Action

One of the central challenges in conducting GEAs is that expert assessments often require knowledge beyond individual expert’s disciplinary expertise. In addition, a closely related challenge is formulating recommendations for action. All interviewees indicated that the primary motivation for participating in the IPCC was to provide science for policy and to influence policymaking. For some, this meant simply communicating scientific facts to policymakers, with the belief that if knowledge is made understandable and relevant, it will naturally lead to action.

However, most interviewees considered this approach to be insufficient. They emphasized that the IPCC must develop and present recommendations and options for action—while carefully maintaining its epistemic authority. The IPCC’s strategy for achieving this balance is to draw a clear boundary between policy relevance and policy prescription [31].

Many respondents expressed that, given the political framework established by the Paris Agreement, the IPCC can maintain scientific credibility by presenting options for achieving these agreed-upon goals, without prescribing specific policies. However, some interviewees argued that as climate change intensifies and the Paris target becomes increasingly urgent, the IPCC must take a more proactive stance in shaping the policy agenda. This view aligns with recent research calling for more ambitious and far-reaching policies to meet the objectives of the Paris Agreement [11,53,54].

At the same time, scholars have emphasized the delicate task for the IPCC’s of balancing science and policy [16,19,55]. Maintaining credibility requires careful navigation of this boundary, ensuring that scientific assessments remain authoritative while still offering meaningful guidance and action.

5.5. Limitations of the Study

Two limitations of the study should be acknowledged. First, there is an element of self-selection among participants. Based on a list of relevant experts, individuals were contacted for interviews. If an individual responded declined or did not respond, another individual with a similar profile was invited. Additionally, participants were asked to suggest other relevant individuals, some of whom were added to the list to enhance both the relevance of the sample and the response rate. In total, approximately 60 experts were contacted and 18 agreed to participate. This means that roughly two-thirds of those invited chose to not participate—either by not declining or not responding. While time constraints may explain some of this non-participation, it is possible that those who declined differ in their experiences or evaluations of the IPCC compared to those who participated.

Second, although the gender composition of the interview sample reflects that of the IPCC experts, regional distribution does not. However, the aim of this study is not to represent the average experience of all IPCC experts. Rather, it seeks to explore how leading experts experience and evaluate the challenges of participating in the IPCC. It is important to note that the small sample size (18 participants) cannot capture the full diversity of experience within the IPCC. The three working groups differ in thematic focus, disciplinary composition, and the type of literature they review, which further complicates generalization.

6. Conclusions

This paper is situated within the context of escalating global environmental challenges and the international community’s continued failure to adequately address them. Climate change persists, with global greenhouse gas emissions now more than 60% higher than in 1990—the year of the IPCC’s first assessment report [41,54]. Biodiversity loss continues, with researchers warning that human actions now threaten more species with global extinction than ever before [56]. The global use of chemicals has surged, resulting in increasingly severe impacts on human health and the ecosystems [20]. An alarming number of planetary boundaries are being crossed; while three boundaries had been exceeded by 2009 [57], six has now been transgressed [58].

These developments have prompted calls for deeper and more radical political commitments [54,59], and for more robust and effective scientific guidance [13]. It is essential to develop scientific advice that is relevant, trustworthy and actionable, and to improve the science–policy interface to better support sustainability transformations [3,4,53]. Equally important is enabling and motivating researchers to devote time to this work. As previous research has shown, scientists often face challenges in allocating time and resources to participate in expert organizations and GEAs [18,60,61]. This paper contributes to this discussion by exploring the opportunities and challenges scientists encounter when participating in GEAs.

While the IPCC has its unique characteristics, other intergovernmental panels—such as IPBES, the Intergovernmental Science–Policy Platform on Biodiversity and Ecosystem Services—operate under broader mandate. Regardless of organizational form, a core task remains the same: to develop, stabilize, and disseminate knowledge relevant to addressing global environmental problems, with the aim of informing and influencing policymaking [62]. Expert organizations conducting GEAs face the same challenge: assessing and synthesizing a broad and complex field of knowledge through the voluntary contributions of experts with highly specialized competencies, often without financial compensation or formal academic recognition for their work [18].

This study of IPCC experts contributes to the ongoing conversation about strengthening the role of science in policymaking and improving the design of the science–policy interface. It highlights the importance of internal robustness within scientific expertise, revealing internal challenges such as epistemic hierarchies and unequal incentive structures that must be addressed. It is not sufficient to build new relationships between science and society; it is also crucial to reflect on the forms of expertise that exist and should be cultivated, and to identify ways for different disciplines and perspectives to collaborate constructively and respectfully.