How relevant is climate change research for climate change policy? An empirical analysis based on Overton data

journals receive more policy citations than can be expected based on science citations such as Climatic Change and Nature Climate Change. These climate change specific journals have emerged more recently. We speculate that the scientific communities of some highly special- ized research topics are comparatively small, thereby limiting the mean number of citations per paper. Nature and Science papers received many citations in both areas of science and policy. The journal analyses in the previous figures could not reveal the field-specific orientation of the papers cited in climate change policy documents. The journals that are labeled in the fig- ures are mostly multi-disciplinary journals such as Science or Nature or are directly related to climate change. In order to explore the fields in which papers cited in climate change policy documents were published, we produced so called overlay maps that are presented in Fig 10. The overlay maps were created using the global mapping process outlined in Boyack and Kla- vans [40]. Here, clustering was done on 46.14 million Scopus-indexed documents (1996–2019) and 27.23 million non-indexed documents cited at least twice with over 1.1 billion citation links using the Leiden algorithm [41]. Graph layout was then done on the resulting 104,677 clusters using OpenOrd/DrL [42] and cluster-level relatedness based on the bm25 text rele- vance measure, which has been shown to produce better clustering than a simple tf-idf mea- sure [43–45]. Over 11% of Scopus-indexed documents were not included in clusters or the map because

they had no references and were not cited. Each cluster is represented as a dot on the map and was assigned to its dominant field (and colored) using the journal-to-field assignments from Fig 8. Average citations per paper of climate change papers in the scientific literature that are cited in policy documents (solid lines) or not (dotted lines). https://doi.org/10.1371/journal.pone.0274693.g008 PLOS ONE How relevant is climate change research for climate change policy? PLOS ONE | https://doi.org/10.1371/journal.pone.0274693 September 22, 2022 13 / 24