Our research examined the use of supplementary materials in six environmental science disciplines: atmospheric sciences, biology, fisheries, forestry, geology, and plant sciences. Ten key journals were selected from each of these disciplines and the number of supplementary materials, such as data files or videos, in each issue was noted over a period of 12 years. A significant rise in the use of supplementary materials was observed for all six subject areas for the study period. Publisher's policies about supplementary materials were also investigated. We analyzed trends in the use of supplementary materials to better support the researchers we work with in these subject areas and to identify ways that librarians can help ensure continued access to these research materials.