Environmental Science Citizen Science
Christopher Kullenberg
  • LAST REVIEWED: 22 September 2021
  • LAST MODIFIED: 22 September 2021
  • DOI: 10.1093/obo/9780199363445-0133


During the past decade the number of citizen science projects around the world has surged. Today there are thousands of initiatives catalogued in databases such as SciStarter.org and EU-Citizen.science, enterprises of which the majority are directly or indirectly linked to scientific research projects. However, citizen science is not a completely novel way of conducting collaborative research; it has been around since the beginning of the scientific revolution and historical data collected by volunteers from the 19th century is used in contemporary research. While citizen science has been most widely used in biodiversity research, conservation, and environmental sciences in need of large-scale observations and monitoring, the approach has today entered a very diverse set of disciplines ranging from the humanities and the social sciences to geography, astronomy, epidemiology, and do-it-yourself technology research. This is largely a consequence of the recent rise and diffusion of digital technologies and communities, notably the Zooniverse.org platform, which makes online classificatory citizen science projects possible at a feasible cost and with a low barrier for mass participation. Consequently, citizen science as a method for collecting and classifying data is in its current state a research design applicable to more or less any empirical line of inquiry. However, volunteer participation in science requires additional considerations to be made that address issues such as the quality of data collected or classified by nonscientists, research ethics concerning attribution and participation in the research design, and ownership of data and results. Furthermore, the expectations of impact may differ between the scientific goals and the participating public’s desire for changes in, for example, environmental policy or species conservation. In 2016 the journal Citizen Science Theory and Practice was launched by the Citizen Science Association, in which current research on the phenomenon is published.

Definition of Citizen Science

There are two major definitions of citizen science in the scientific literature. Also, there is an array of related concepts that are sometimes used as synonyms, and sometimes to describe a particular aspect of citizen science or a specific context in which knowledge is generated. Briefly summarized, the first and predominant definition throughout the literature originates in the natural sciences, in which the notion of citizen science generally refers to volunteer engagement in collecting and classifying empirical data. Within this definition, the central components of citizen science include issues of data quality and volunteer engagement, while questions regarding learning, empowerment and citizenship are of lesser interest, even though such problems have entered both scientific debate and scholarly research in recent years due to the increased popularity and institutionalization of citizen science. This first definition of citizen science is the main focus of this article, and notable works along these lines are Silvertown 2009; Goodchild 2007; and Bonney, et al. 2009. The second major definition arises from the social sciences and refers to citizen science in terms of scientific citizenship, the relationship between laypersons’ and expert knowledge, and public trust in scientific knowledge. At the heart of this research is the citizen, and his or her way of enacting citizenship in relation to science. This research often draws from social science methods to inquire about stakeholder dialogues, science communication, and institutional trust. Irwin 1995 is the most influential work using this definition of citizen science. In addition to these two common definitions, there are several related concepts in the literature, some of which are synonymous, while others emphasize specific qualities of the involvement of nonscientists in science. “Crowd science” and “crowdsourcing” are often used in engineering research, for example in Franzoni and Sauermann 2014. “Community-based monitoring”, “environmental monitoring,” and “citizen observatories” are often interchangeable with citizen science in the natural sciences, as highlighted in Danielsen, et al. 2005. Moreover, “volunteered geographic information,” “neogeography,” or “VGI” are common within geography and cartography, as discussed in Haklay 2013. Furthermore, in the parts of the literature that highlight community participation and empowerment, common terms include “street science,” “popular epidemiology,” “civic science,” “extreme citizen science,” and “participatory science.” These various conceptualizations of citizen science were analyzed bibliometrically in Kullenberg and Kasperowski 2016, and were more recently described in Pelacho, et al. 2021. As a broad overview of the historical and social aspects of the definition of citizen science, Eitzel, et al. 2017 provides a critical discussion from the perspective of several leading scholars in the field, including a problematization of the sometimes Eurocentric view on science and citizenship.

  • Bonney, R., C. B. Cooper, J. Dickinson, et al. 2009. Citizen science: A developing tool for expanding science knowledge and scientific literacy. BioScience 59.11:977–984.

    DOI: 10.1525/bio.2009.59.11.9

    Draws on twenty years of experience with citizen science in species distribution research at the Cornell Lab of Ornithology, which has been highly influential in shaping citizen science as a method for the natural sciences.

  • Danielsen, F., N. D. Burgess, and A. Balmford. 2005. Monitoring matters: Examining the potential of locally-based approaches. Biodiversity & Conservation 14.11:2507–2542.

    DOI: 10.1007/s10531-005-8375-0

    A central work that discusses the low-cost benefits and resource management of citizen science, while still maintaining a sensitivity toward stakeholder participation issues.

  • Eitzel, M. V., J. L. Cappadonna, C. Santos-Lang, et al. 2017. Citizen science terminology matters: Exploring key terms. Citizen Science: Theory and Practice 2.1:1

    DOI: 10.5334/cstp.96

    A conceptual article written by eleven leading scholars in the field of citizen science that discusses the various terms used for labeling citizen science activities. The authors take into account the Eurocentric aspects that have been present in the definition of citizen science and proceed to bring into light several global alternatives. Moreover the article thoroughly discusses power aspects that are inherent in describing both the notion of citizenship and what it entails to be a scientist.

  • Franzoni, C., and H. Sauermann. 2014. Crowd science: The organization of scientific research in open collaborative projects. Research Policy 43.1:1–20.

    DOI: 10.1016/j.respol.2013.07.005

    Focuses on how the scientific method and ethos of knowledge, for example openness and universality, is realized in citizen science projects, also known here as “crowd science.”

  • Goodchild, M. F. 2007. Citizens as sensors: The world of volunteered geography. GeoJournal 69.4:211–221.

    DOI: 10.1007/s10708-007-9111-y

    The most well-cited research article in citizen science literature, conceptualizing the “citizen as sensor” in the context of emerging geographical information systems.

  • Haklay, M. 2013. Citizen science and volunteered geographic information: Overview and typology of participation. In Crowdsourcing geographic knowledge. Edited by D. Sui, S. Elwood, and M. Goodchild, 105–122. Dordrecht, The Netherlands: Springer.

    DOI: 10.1007/978-94-007-4587-2_7

    One of the most important texts within the field of volunteered geographic information, stemming from the “extreme citizen science” research group.

  • Irwin, A. 1995. Citizen Science: A Study of People, Expertise, and Sustainable Development. London: Routledge.

    Regarded as a pioneering work in the relationship between citizens and science, from the perspective of social studies of science. In this book, Irwin discusses the problems of an expert-driven society guided by scientific knowledge and the challenges for public trust and citizenship such a society entails.

  • Kullenberg, C., and D. Kasperowski. 2016. What is citizen science?—A scientometric meta-analysis. PLoS ONE 11.1.

    DOI: 10.1371/journal.pone.0147152

    A scientometric analysis mapping the research literature on citizen science through various definitions, conceptualizations, and terms. This article shows both the various origins of the concept of citizen science as well as the multiple applications of the method.

  • Pelacho, M., G. Ruiz, F. Sanz, A. Tarancón, and J. Clemente-Gallardo. 2021. Analysis of the evolution and collaboration networks of citizen science scientific publications. Scientometrics 126.1:225–257.

    DOI: 10.1007/s11192-020-03724-x

    A more recent scientometric analysis of the citizen science literature and its multiple concepts and recent growth in the publication databases. The authors trace various terms used synonymously with citizen science, and also analyze the coauthor networks as well as national scientific productivity.

  • Silvertown, J. 2009. A new dawn for citizen science. Trends in Ecology & Evolution 24.9:467–471.

    DOI: 10.1016/j.tree.2009.03.017

    A programmatic text connecting the recent trend of citizen science with the dawn of the scientific revolution. Here it is argued that key figures in modern science, such as Darwin or Newton, were in fact rather like citizen scientists.

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