Over 500 delegates took part in the third international ECSA conference in September 2020. Across 30 sessions, as well as keynote talks, e-poster presentations and more informal settings, they discussed and debated a diverse range of subjects related to citizen science. This special edition of ‘JCOM’ brings together some of the central themes that were under the spotlight at ECSA 2020. Since ECSA 2020 has been one of the first examples of a conference that moved completely online, and it has been considered a big success, we also include the Conference Report, as supplementary material with this editorial.

Citizen science involves laymen in some steps of a scientific experiment: citizens are volunteers devoting their free time to citizen science projects. Therefore it is important to investigate the factors influencing their motivation and engagement. In this paper, we present our study to investigate the motivation factors of the TESS photometer network participants, an initiative to collect light pollution data. We present the results and insight of our investigation and the instrument we adopted, which can be useful for the broad citizen science community.

WeObserve delivered the first European-wide Citizen Observatory (CO) knowledge platform to share best practices, to address challenges and to inform practitioners, policy makers and funders of COs. We present key insights from WeObserve activities into leveraging challenges to create interlinked solutions, connecting with international frameworks and groups, advancing the field through communities of practice and practitioner networks, and fostering an enabling environment for COs. We also discuss how the new Horizon Europe funding programme can help to further advance the CO concept, and vice versa, how COs can provide a suitable mechanism to support the ambitions of Horizon Europe.

Undertaking citizen science research in Public Health involving human subjects poses significant challenges concerning the traditional process of ethical approval. It requires an extension of the ethics of protection of research subjects in order to include the empowerment of citizens as citizen scientists. This paper investigates these challenges and illustrates the ethical framework and the strategies developed within the CitieS-Health project. It also proposes first recommendations generated from the experiences of five citizen science pilot studies in environmental epidemiology within this project.

Scientists highlight that actions that address environmental protection and climate change can also help with reducing infectious disease threats. Results using data from a national sample survey in New Zealand indicate that perceptions of co-benefits of actions to address environmental protection that also protect against infectious disease outbreaks such as the coronavirus is associated with policy support and political engagement. This association was partly mediated through perceived collective efficacy. Local councils with higher level of community collective efficacy were more likely to declare climate emergency. Communication about potential co-benefits is likely to shape public engagement and enact policy change.

The promise of CRISPR-Cas9 (CRISPR) genomic editing applied to agriculture is promoted widely by scientists. We utilized textual analysis methods to compare perceptions of this innovation held by various stakeholder groups — scientists, policymakers, farmers, and the general public. Results reveal distinctions in the semantic structure and concepts emphasized across groups. Scientists and policymakers exhibited a high level of technical sophistication while emphasizing the potential societal benefits, while farmers and the general public focused on perceived personal benefits and familiarity with the issue. These results will aid development of message strategies bridging the gap between the scientific community and key publics.

Co-created citizen science offers practical tools for implementing science communication theories by increasing public participation in scientific research, empowering communities and advancing situated scientific knowledge. However, delivering such an approach presents a number of key challenges around funding, fostering working partnerships between scientists and citizens and ensuring all stakeholders receive sufficient benefits from the process. In this essay we draw from science communication and citizen science literature to describe these challenges and discuss the opportunities that will enable co-created practices to prosper.

The inaugural "Mr. Science" Science Communication Conference was held in Suzhou, China on July 9, 2021. It was the largest Chinese conference on science communication study since the start of the 21st century. More than 260 scholars discussed the spirit and culture of science, science communication during the COVID-19 crisis, the public understanding of science, and the ethical aspects of science communication. The conference aimed to develop a system for researching science communication within China. This review outlines the content of the conference and summarizes the key trends in science communication research in China.

A novel and original take on the history of popular science showcases that making science accessible to the public has been part of scientific activity since ancient times. Under this lens, and through twenty-one case studies, current trends such as sci-art and virtual technology can be seen as part of a continuum that was already present in the use of aesthetic and rhetorical tools by the ancient Greeks. Thanks to a careful curation of the collection of texts, this volume as a whole offers more than the sum of its parts (chapters).

This study examines early-career scientists' cognition, affect, and behaviors before, during, and after a series of science communication training workshops drawing from the Risk Information Seeking and Processing (RISP) and Theory of Planned Behavior theoretical models. We find correlations between engagement (throughout the training), self-reported knowledge and intention to apply their science communication skills. We discuss implications of these findings for science communication training, in particular that science communication behaviors and investment in skill development appear to be more dependent on attitudes and motivations cultivated during the training, rather than their attitudes and motivations coming in.