The New Climate Activism provides important and timely insights into why some civil society activists have successfully inserted their issues into the climate change regime, while others remain outside it. Allan provides a theory of “forum multiplying,” whereby activists from other issue areas—including labour, human rights, gender, climate justice, and health—mobilize to insert themselves into the intergovernmental climate negotiations that occur under the auspices of the United Nations Framework Convention on Climate Change (UNFCCC).

Allan offers a cogent and sensible explanation of forum multiplying. In order to be successful, nongovernmental organizations (NGOs) must first identify and organize around a discursive frame that links their issue to climate. For example, the network of gender NGOs focused on women's ability to contribute to climate solutions, as well as the disproportionate effects of climate change on women. Second, NGOs must identify allies within the climate regime who vouch for them and introduce them into the existing network of climate NGOs. In other words, as with all networks, it helps to have an “in.” And finally, new climate activists have to “leverage institutions”—finding ways to connect their issues to ongoing debates or rules within the climate regime. The climate justice movement, for instance, focused its efforts on critiques of market mechanisms in the UNFCCC, thereby establishing a clear link between its own views and ongoing policy debates.

Allan's monograph is an excellent contribution to the climate politics and civil society literatures on several counts. Her study contributes to the large body of literature on the proliferation of climate-related international institutions and actors, providing a partial explanation for why this proliferation of actors has occurred. In addition, the book provides insights into the all-important question for political scientists: How do actors gain authority? In the case of civil society, Allan's answer has to do much more with friends and framing than with material resources. For NGOs, at least, money does not necessarily translate to authority; this is consistent with other works that indicate that credibility and legitimacy from multiple audiences is a critical currency for NGOs (see, for example, Gourevitch et al., Reference Gourevitch, Lake and Stein2012; Stroup and Wong, Reference Stroup and Wong2017). Third, like Hadden's book Networks in Contention (Reference Hadden2015), Allan's work reminds us of the heterogeneity of climate-related NGOs—in terms of the ways they frame climate change, the issues they focus on (adaptation versus mitigation) and the tactics they use. This is not a simple descriptive exercise of their variation; it contributes to her theoretical explanation of whether and how NGOs can leverage this heterogeneity to exercise authority in new political arenas.

But the real strength of the book lies in its careful research design and detailed empirical work. Allan presents five cases of both successful and unsuccessful instances of forum multiplying. Using social network analysis, she maps the interface between the NGOs in each issue area and climate NGOs—an impressive empirical accomplishment in and of itself.

Allan also has incredible knowledge of the ins and outs of the UNFCCC process, as reflected in the depth of the qualitative data. As a reporter for the Earth Negotiations Bulletin, she participated in 12 of the 15 UNFCCC meetings between June 2012 and December 2015—the period during which the bulk of the Paris Agreement was negotiated. With access to the negotiations, she conducted 72 interviews of Secretariat staff, NGOs, and others participating in the international negotiations. Put quite simply, excluding career negotiators, Allan is one of the foremost experts on the Paris Agreement.

The qualitative and quantitative analyses support her findings. She shows that the structure of an NGO network does not determine successful forum multiplying. Rather, the effective use of discursive frames, institutional rules and allies are the key determinants of success. Indeed, labour had a very centralized network through the International Trade Union Confederation, while gender NGOs were much more fragmented, with several different organizational hubs and subgroups. Despite their different structures, both were able to link their issues to climate-related frames and institutions. Labour crafted the broad policy frame of a just transition to accommodate the varying views of those within the network. Gender NGOs pivoted from more controversial discussions about reproductive rights, focusing instead on how women were disproportionately affected by climate change and could serve as agents for positive changes. Allan also notes that finding the right frame may have unintended effects, as illustrated in the case of climate justice. While the term is now well integrated into the Paris Agreement, it has been co-opted by more centrist groups. As a result, “the climate justice frame spread in directions the members of the justice movement never intended” (119).

My quibbles with Allan's book are just that: small points that do not undermine the excellent quality of the overall contribution. Allan seeks to understand how NGOs gain authority in the climate arena, but as she herself notes, she is actually measuring recognition. While she notes that “recognition is an important precursor to authority” (12), the two are not the same. Thus, it is possible that successful forum multiplying does not translate to more authority, but she does not explore the implications of this possibility. Second, and relatedly, the book raises critical unanswered questions about the effects of having increasingly diverse civil society networks involved in the UNFCCC process. While sustainable development governance has permanent aspirations for multi-stakeholder participation, a diversity of actors can overwhelm negotiations. The book would benefit from at least some preliminary discussions of these trade-offs. These issues notwithstanding, Allan's book is an excellent contribution to the literatures on non-state actors and climate politics and will surely serve as a reference for both students and scholars.