A portfolio of outputs advancing a new research agenda on citizen science and participatory mass observation. These included practice-based outputs (three prototypes and a curated art exhibition) and an Editorial and Special Section of the journal Leonardo.The three year interdisciplinary project conceived and led by Hemment investigated how scientific understanding can be augmented and enhanced by participatory art and design combining social media with sensing and geo-locative technologies. It involved collaboration between artists, technologists, game designers and social, natural and citizen scientists to collaboratively produce, share and make sense of information about local climate, environment and biodiversity. A high proportion of the research was practice-based and involved various publics in exploration of the research questions.Three participatory prototypes (www.futuresonic.com/09/env20) were deployed and evaluated. One (Climate Bubbles, 2009) tested a participatory and playful method for the public to generate local climate data the Met Office could not capture in any other way. An exhibition surveying this emerging field was presented at CUBE (Manchester, 13-23 May 2009) and Peter Scott (Lancaster, 7-31 October 2009) galleries featuring 30 international projects.Further reflection through a solo editorial by Hemment and co-authored papers on the project overall, on the prototypes and on the survey in the journal Leonardo. The papers were co-authored with participating artist-designers and citizen scientists; collaborators at Lancaster Environment Centre; and scientists from the Met Office, Open Air Laboratories Network and Natural History Museum. Environment 2.0 had international impact through workshops at ISEA08 (Singapore, 2008), Transmediale09 (Germany, 2009) and Futuresonic (UK, 2009).Funded by the Met Office, Open Air Laboratories Network, Arts Council England, Lancaster University and the EPSRC Digital Economies CREATOR Cluster.Resulted in a new European grouping collaborating in EU bids, and contributed to the framing of EUPORIAS a €13M FP7 project.