Over the last decade, rapid advances in ICT, computing, communication technologies (e.g., smartphones and web 2.0 technologies), and a generally growing geo-literacy, have enabled non-specialists to participate in truly scientific endeavors. This so-called “Citizen Science”, as well as the related concepts of crowdsourcing and volunteered geographic information (VGI), support both fundamental research and societal applications, and come in many forms, such as observations of biodiversity, validation of remote sensing maps, or support of post-disaster response through smartphone-based provision of ground information or collective image-based damage mapping. In particular, Citizen Science observations from low-cost sensors, phones and Citizen Observatories, provide a novel and recent development in platforms for observing the Earth System, with the opportunity to extend the range of observational platforms available to society to spatio-temporal scales (10-100s of metres; 1 hour or less) highly relevant to citizen needs. The potential value of Citizen Science is high, with applications in science, education, social aspects, and policy aspects, but this potential, particularly for citizens and policymakers, remains largely untapped. Nevertheless, key areas where Citizen Science data start to have demonstrable benefits include the GEOSS Societal Benefit Areas of Health (e.g., estimating exposure to atmospheric pollutants) and Weather (e.g., providing precipitation forecasts).

In the geosciences Citizen Science has also seen a growing importance, e.g., in the creation of reference data sets, training of models, or validation of mapping results. Contrasting the vast potential such approaches hold are challenges related to data accuracy and validation, spatial bias, sustainability of citizen science projects, or the maximizing of synergy between novel crowd-based approaches and traditional methodologies.

Citizen Science observations have many challenges, including simulation of smaller spatial scales, noisy data, combination with traditional observational methods, and assessment, representation and visualization of uncertainty. Within these challenges, that of the assessment and representation of uncertainty and its communication to users is fundamental, as it provides qualitative and/or quantitative information that influences the belief users will have in environmental information.

Recognizing the growing importance of Citizen Science as a new paradigm in research, and the unique opportunity it offers to tap into the enormous passion and good will of a wide community of citizens, papers are invited that highlight novel insights into the optimal use of citizen science approaches, their combination and integration with traditional methods, optimal and scientifically rigorous ways to train and steer a crowd contributing to a geoscience problem, communication aspects in citizen science, or the role these methods can play in education and in bringing science closer to society. In addition, this session will focus on the assessment and representation of uncertainty in Citizen Science observations, its communication to users, including the use of visualization, and the perception of this uncertainty information by users of Citizen Science observations.