Who tweets climate change papers? investigating publics of research through users’ descriptions

change: policy responses to protect public health). The paper Oxygen isotope in archaeological bioapatites from India: Implications to climate change and decline of Bronze Age Harappan civi- lization has close to half (45.2%) of its Professional assignations not overlapping with any other categories (S4 Table in S1 File). Two papers, Global and regional health effects of future food production under climate change: a modelling study and Assessing the Performance of EU Nature Legislation in Protecting Target Bird Species in an Era of Climate Change, have a low share of overlap with Communication at respectively 6.3% and 8.9%. However, this paper has a large share of overlap with the Personal category at 57.8%. Overall, Professional and Personal overlapping is high across all the most tweeted papers, with the lowest at 29.8%. The largest share of Personal assignations is with the most tweeted paper, Climate change in the Fertile Crescent and implications in the recent Syrian drought, at 34.7%, whereas two papers (Oxygen isotope in archaeological bioapatites from India: Implications to climate change and decline of Bronze Age Harappan civilization at 21.2% and Ecological networks are more sensitive to plant than to animal extinction under climate change at 21.4%) have the lowest share. These two papers represent both extremes of the range of unique assignations, at respectively 47.4% and 18.6% of accounts assigned to the Personal category (S5 Table in S1 File). The second most important share of unique assignations is with the paper Climate change in the Fertile

Crescent and implications in the recent Syrian drought at 42.9%. The paper Ecological networks are more sensitive to plant than to animal extinction under climate change show here again a high overlap of Personal assignations with the Academia category, at 59.3%. Finally, the paper Assessing the Performance of EU Nature Legislation in Protecting Target Bird Species in an Era of Climate Change has a low overlap of Personal assignations with the Communication cate- gory (7.8%) while high with the Professional category (33.8%). These results highlight the sig- nificant use of personal identity markers across all publics. In this regard, users assigned only to the Personal category may represent what is coined as the lay public. Discussion A key challenge in assessing who tweets scholarly documents through Twitter profile descrip- tions is defining the use and meaning of identity markers in expressions employed by users. Analysis relying only on Twitter data is a complex endeavor as we seldom know who is exactly behind an account. To circumvent some of these issues, our analysis categorized profile according to eight types of users sharing climate change research papers on Twitter. Specifi- cally, we categorized expressions and keywords used in Twitter profile descriptions to assess how they represent identity markers, and so type of users sharing climate change research papers. As with other studies, the detection of words related to the academic world is precise in that it reflects potential individual users involved in research, although it does not distin-

guish how close their research interests are to the topic at hand [57, 76]. The overlap with other categories also shows how actors of research are not restricted to this role, whether through communicational (science communication), professional (administrative functions), political (policy making) or simply personal (being a parent, having pets, hobbies) activities [77]. Profiles categorized in Communication mostly encompasses journalists and communica- tion professionals, authors, artists, and overlaps with political and professional expressions represents users who may engage in political campaigning, policymaking. Political assigna- tions highlight users who present themselves through social issues and activism, some through related professional work. Professional assignations highlight those whose work relate closely to climate change mitigation efforts, for example risk management, or other specific profes- sional activities, such as veterinarians or lawyers. Finally, personal assignations indicate how users identify themselves through their hobbies or personal interests and relationships. When PLOS ONE Who tweets climate change research papers? PLOS ONE | https://doi.org/10.1371/journal.pone.0268999 June 3, 2022 11 / 17