Studying the impacts of global climate change on ecological systems requires data to be gathered at vast spatial and temporal scales. While much data can be gathered by remote sensors and professional researchers, volunteer data collectors, sometimes known as citizen scientists, are playing an ever-increasing role. Many data-collection schemes that allow environmental information to be collected through standardized protocols and submitted to centralized databases are now under way throughout the world, and their number increases each month. Some projects span countries and continents and have been operating for decades, so they have already produced long-term and geographically disparate data that are easily accessible for analysis. Examples include the North American Breeding Bird Survey, the National Audubon Society Christmas Bird Count, numerous atlases of animals and plants, and predecessors to the US National Phenology Network such as lilac and honeysuckle observation networks. These projects have yielded data on flowering, leaf out, and nesting patterns which have significantly informed understanding of the effects of climate on phenology. They also have yielded records of plant and animal distributions which have documented significant shifts in species’ ranges. Such findings will be covered in detail by the varied papers in this symposium.
Results/Conclusions
While the number of published articles based on citizen science data grows each year, some ecologists continue to question the integrity of data collected by the public. In fact, citizen science projects employ many strategies for ensuring data quality. These include formative testing of project protocols, project support materials such as identification guides and tutorials, and participant training workshops. In addition some programs, such as eBird, use automated filters to examine incoming data for accuracy. As the citizen science field employs increasingly sophisticated methods for data compilation, visualization, and analysis, opportunities for using citizen science techniques to study large-scale environmental patterns will continue to grow. 
In addition, citizen science presents significant opportunities for developing public understanding of climate change and its consequences. Evaluations of citizen science projects have shown that participants increase their knowledge of science content and process and sometimes become more involved in community conservation efforts. A similar benefit may accrue to participants in projects focused on documenting the effects of climate change. To further climate change research and education, we urge the continued growth of the citizen science field and study of its educational benefits as well as use of its growing banks of data.