Using citizens’ assemblies to shape climate policy: A summary of current thinking for policymakers and practitioners
Key messages:
Participating in National Citizens’ Climate Assembly (NCCAs) can boost individuals’ climate change knowledge and encourage sustainable behaviour.
NCCAs to date appear to have had limited influence on climate policy. This may be because policy processes struggle to integrate recommendations from assemblies.
Assembly outcomes are affected by the assembly’s format and focus, which are often decided by policy actors.
Views amongst publics, practitioners, academics and policymakers on the roles and purposes of NCCAs vary greatly. People who participate in NCCAs are often supportive of the process, but policymakers can be less so.
Each NCCA is unique. The distinctiveness of each assembly affects its impact, which may unfold over a very long period of time. It is therefore difficult to predict the short- and long-term impacts of individual assemblies.
Recent studies have argued that the design of assemblies (e.g. how evidence is formatted and communicated, membership composition) can facilitate value-based deliberations, leading to opportunities for wider learning, even questioning more deeply the policy status quo and consideration of more diverse options for climate action.

CAST is a global hub for understanding the crucial role that people play in fighting climate change. The CAST team is based across five UK institutions, including the University of Bath (our centre hub), the University of Manchester, the University of East Anglia and Cardiff University, as well as the charity Climate Outreach.
Introduction
This briefing is intended as a resource for policymakers and practitioners examining the role and contribution of national-level deliberative events to climate policy. For further information, read the paper: “A review of National Citizens’ Climate Assemblies: learning from deliberative events”.
Over the past decade, Europe has witnessed increased interest in National Citizens’ Climate Assemblies (NCCAs) as a means to engage the public in conversations and decisions about climate change policy (see Figure 1 and Table 1 in Appendix). NCCAs are generally comprised of 100-150 people (usually national citizens, selected randomly according to key socio-demographic and/or other characteristics), known as assembly members. The focus of each assembly and its mode of working is often set in advance (by commissioning institutions, funders, etc.). The discussions (or ‘deliberations’) are generally facilitated and often include input from ‘experts’. The assembly members consider the topics and discussions, reaching some formal recommendations for how to address specific climate change issues and inform policy.
Advocates of NCCAs have argued that they: (a) improve the quality of climate policymaking, by providing more evidence on which to make policy decisions; and (b) offer a process more representative of diverse publics than existing governance systems, thereby potentially enabling the creation of more ambitious policy that considers a wider range of public views and meets a wider range of public needs. However, the impacts of NCCAs are still not fully understood. This briefing summarises current thinking and evidence on how NCCAs work, how they are perceived, and what they have achieved.
Methods
Researchers at the Centre for Climate Change and Social Transformations (CAST) reviewed the recent academic literature on NCCAs. Articles and reports were gathered by searching the academic databases Google Scholar and Web of Science. This returned 25 academic publications that referred specifically to NCCAs, published between 1 January 2013 and 9 December 2024. Also included were documents discussing climate assemblies, citizens’ assemblies, and deliberative events more generally, to provide greater depth and context.

Background

Figure 1: Timeline of National Citizens' Climate Assemblies in Europe

Findings
1)		Participating in NCCAs can boost climate change knowledge and encourage sustainable behaviour
Participating in NCCAs has benefits for assembly members, including providing opportunities for acquiring information, debating and exchanging ideas, discussing views and materials shared, and deliberating potential climate solutions. Having time to think about climate change also seems to affect assembly members, who sometimes indicate that the experience of taking part makes them more concerned about climate change. As a result, many assembly members make behavioural changes and are more supportive of deliberative approaches in general.
That said, negative experiences of NCCAs can lead members to become more dubious about the policy influence of assemblies. Some scholars have also questioned the legitimacy of ‘nationally representative’ groups to propose recommendations for policy, arguing that assembly membership should also cover the perspectives of those most directly affected by issues discussed. For example, in climate assemblies, these could be younger generations, and others impacted by climate change (e.g., coastal communities experiencing sea level rise) or climate policies (e.g., workers in oil and gas industries).
2)		Policymakers do not always support NCCAs
Policymakers’ and leaders’ views of assemblies are less clear cut. Politicians generally perceive assemblies to challenge existing democratic processes, thereby undermining the roles and authority of politicians. Some argue that assemblies do not currently have the democratic/representative legitimacy that democratic theorists purport they should. However, some studies have also found that when elite actors take part in assemblies, they view them more positively.
3)		NCCAs’ impact on policymaking is limited
Despite normative theoretical arguments in favour of NCCAs, few NCCAs to date have had a clear and evident effect on policy making. This may be for several reasons.
First, policymaking processes are not always able to consider and integrate the suggestions from assemblies. However, alternative formats are being considered to overcome this, including reforming existing democratic structures to incorporate assemblies directly, or enabling existing processes to consider proposals emerging from such events in more depth and/or over longer periods of time. For example, in 2023, both Brussels and Milan launched permanent citizens’ assemblies on climate change.
Second, assembly organisers/sponsors may exert influence on the assembly via their choice of topics/questions to be discussed, the format of the deliberations and their response to the assembly recommendations. Scholars and assembly experts have called for more inclusive and bottom-up NCCA formats – for example, by ensuring a diverse group of individuals is included and by giving members more control over the assembly agenda and its processes.
Third, it is challenging to draw broad conclusions on NCCAs’ impact because, although NCCAs are largely designed and run based on common deliberation principles (e.g. selection of participants, key question to address, facilitation, production of recommendations), their specific features are context dependent. Each NCCA is unique. These features determine the outcomes and some impacts of the assembly. Studies have, in fact, shown that the impacts of assemblies can occur over much longer periods than may initially be expected. Evaluations should therefore specify the key criteria and time period applied in the assessment.
Conclusion
The rapidly proliferating literature on NCCAs reflects some of the hope placed in such approaches to help address the perceived inability of current democratic systems to deal effectively with climate change. Whilst NCCAs may challenge existing structures, the lack of a clear political mandate has in part reduced their short-term influence on climate decision making. More recent studies indicate that NCCAs have fostered and are spurring related innovations in deliberative decision making that are being trialled in other more localised contexts, outside Europe. However, it is too soon to assess how these more localised innovations further or differ the progress achieved by NCCAs.
Recommendations
Policymakers and practitioners interested in using NCCAs in climate decision-making should:
Treat each assembly as a unique case defined and bounded by the context in which it is undertaken.
Consider reviewing the impact of assemblies over longer time periods. Suitable evaluation frameworks should be applied to support such assessments.
Exercise caution: although climate assemblies enable citizen deliberation, they are not a panacea when it comes to addressing climate policy change.
Consider other formats for climate deliberation: bringing together a wider array of perspectives (e.g. both policymakers and publics) in the same spaces may enable greater learning and understanding. Other deliberative processes – more localised, different formats- may also result in deeper challenges to the status quo.
Explore lessons from other assemblies which have been embedded into formalised structures of local decision making to assess their impacts and ‘successes’.
Further reading
Boswell, J., Dean, R., & Smith, G. (2023). Integrating citizen deliberation into climate governance: Lessons on robust design from six climate assemblies. Public Administration, 101(1), 182–200. https://doi.org/10.1111/padm.12883
Demski, C., Capstick, S., & Hessellund Beanland, M. (2024). Impact evaluation framework for climate assemblies. Updated framework. KNOCA (Knowledge Network on Climate Assemblies). https://www.knoca.eu/guidances-documents/impact-evaluation-framework
Elstub, S., Carrick, J., Farrell, D. M., & Mockler, P. (2021). The scope of climate assemblies: Lessons from the Climate Assembly UK. Sustainability, 13(20), 11272. https://doi.org/10.3390/su132011272
Harris, C., Farrell, D. M., & Suiter, J. (2023). Mixed-member deliberative forums: Citizens’ assemblies bringing together elected officials and citizens. Chapter 12. In M. Reuchamps, J. Vrydagh, & Y. Welp (Eds.), De Gruyter Handbook of Citizens’ Assemblies. Berlin, Boston: De Gruyter. https://doi.org/10.1515/9783110758269
Lorenzoni, I., Jordan, A. J., Sullivan-Thomsett, C., & Geese, L. (2025). A review of National Citizens’ Climate Assemblies: learning from deliberative events. Climate Policy, 25(9), 1546– 1562. https://doi.org/10.1080/14693062.2024.2449416
Thorman, D., & Capstick, S. (2022). Planning and assessing the impact and legacy of climate assemblies. KNOCA Briefing no.4, KNOCA. https://www.knoca.eu/briefings/the-legacy-and- impact
Torney, D. (2021). Deliberative mini-publics and the European green deal in turbulent times: The Irish and French climate assemblies. Politics and Governance, 9(3), 380–390. https://doi.org/10.17645/pag.v9i3.4382
Suggested citation:
Lorenzoni, I., Jordan, A., Sullivan-Thomsett, C. and Geese, L. (2025) “Using citizens’ assemblies to shape climate policy: a summary of current thinking for policymakers and practitioners”. CAST Briefing 43. Available at: https://cast.ac.uk/wp-content/uploads/2025/11/the-centre-for- climate-change-and-social-transformations-cast-briefing-43-using-citizens-assemblies-to-shape- climate-policy-a-summary-of-current-thinking-for-policymakers-and-practitioners.pdf

Appendix

			

			

			
			
Table 1: National citizens’ climate assemblies in Europe to date. Since this research was undertaken, an NCCA was also held in the Netherlands (Jan-June 2025). The Finnish citizens’ jury is also included, as it is sometimes considered an NCCA.

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