This bibliometric study of a large publication set dealing with research on climate change aims at mapping the relevant literature from a bibliometric perspective and presents a multitude of quantitative data: (1) The growth of the overall publication output as well as (2) of some major subfields, (3) the contributing journals and countries as well as their citation impact, and (4) a title word analysis aiming to illustrate the time evolution and relative importance of specific research topics. The study is based on 222,060 papers (articles and reviews only) published between 1980 and 2014. The total number of papers shows a strong increase with a doubling every 5–6 years. Continental biomass related research is the major subfield, closely followed by climate modeling. Research dealing with adaptation, mitigation, risks, and vulnerability of global warming is comparatively small, but their share of papers increased exponentially since 2005. Research on vulnerability and on adaptation published the largest proportion of very important papers (in terms of citation impact). Climate change research has become an issue also for disciplines beyond the natural sciences. The categories Engineering and Social Sciences show the strongest field-specific relative increase. The Journal of Geophysical Research, the Journal of Climate, the Geophysical Research Letters, and Climatic Change appear at the top positions in terms of the total number of papers published. Research on climate change is quantitatively dominated by the USA, followed by the UK, Germany, and Canada. The citation-based indicators exhibit consistently that the UK has produced the largest proportion of high impact papers compared to the other countries (having published more than 10,000 papers). Also, Switzerland, Denmark and also The Netherlands (with a publication output between around 3,000 and 6,000 papers) perform top—the impact of their contributions is on a high level. The title word analysis shows that the term climate change comes forward with time. Furthermore, the term impact arises and points to research dealing with the various effects of climate change. The discussion of the question of human induced climate change towards a clear fact (for the majority of the scientific community) stimulated research on future pathways for adaptation and mitigation. Finally, the term model and related terms prominently appear independent of time, indicating the high relevance of climate modeling.

We introduce the quantitative method named "Reference Publication Year Spectroscopy" (RPYS). With this method one can determine the historical roots of research fields and quantify their impact on current research. RPYS is based on the analysis of the frequency with which references are cited in the publications of a specific research field in terms of the publication years of these cited references. The origins show up in the form of more or less pronounced peaks mostly caused by individual publications that are cited particularly frequently. In this study, we use research on graphene and on solar cells to illustrate how RPYS functions, and what results it can deliver.

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The highly popular journal impact factor (JIF) is an average measure of citations within 1 year after the publication of a journal as a whole within the two preceding years. It is widely used as a proxy of a journal's quality and scientific prestige. This article discusses misuses of JIF to assess impact of separate journal articles and the effect of several manuscript versions on JIF. It also presents some newer alternative journal metrics such as SCImago Journal Rank and the h-index and analyses examples of their application in several subject categories.

Although bibliometrics has been a separate research field for many years, there is still no uniformity in the way bibliometric analyses are applied to individual researchers. Therefore, this study aims to set up proposals how to evaluate individual researchers working in the natural and life sciences. 2005 saw the introduction of the h index, which gives information about a researcher's productivity and the impact of his or her publications in a single number (h is the number of publications with at least h citations); however, it is not possible to cover the multidimensional complexity of research performance and to undertake inter-personal comparisons with this number. This study therefore includes recommendations for a set of indicators to be used for evaluating researchers. Our proposals relate to the selection of data on which an evaluation is based, the analysis of the data and the presentation of the results.

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We introduce a new toolthe CitedReferencesExplorer (CRExplorer, www.crexplorer.net)which can be used to disambiguate and analyze the cited references (CRs) of a publication set downloaded from the Web of Science (WoS). The tool is especially suitable to identify those publications which have been frequently cited by the researchers in a field and thereby to study for example the historical roots of a research field or topic. CRExplorer simplifies the identification of key publications by enabling the user to work with both a graph for identifying most frequently cited reference publication years (RPYs) and the list of references for the RPYs which have been most frequently cited. A further focus of the program is on the standardization of CRs. It is a serious problem in bibliometrics that there are several variants of the same CR in the WoS. In this study, CRExplorer is used to study the CRs of all papers published in the Journal of Informetrics. The analyses focus on the most important papers published between 1980 and 1990.

The current citations of 19th century papers have recently received considerable attention [1]. Among them is an article by Rudolf (Hermann Arndt) Kohlrausch (*1809, † 1858) [2] in which he introduced the stretched exponential function Qcharge relaxation in a Leiden jar. This work was essentially forgotten throughout most of the 20th century until the appearance of Ref. 3. Unfortunately, R.G. Palmer et al. [3] do not refer to the correct paper by R. Kohlrausch [2], referring instead to an earlier Kohlrausch paper [4] in which he only qualitatively describes relaxation phenomena in galvanometer threads. The fact that such mechanical relaxation can also be represented by the stretched exponential function was not published until many years later by Friedrich (Wilhelm Georg) Kohlrausch (*1840, † 1910) [5], the son of Rudolf Kohlrausch. Therefore, the credit for the introduction of the concept is sometimes given to him. But the first time the stretched exponential function appeared in the literature is 1854 in [2].