What mathematical skills, particularly in the area of reasoning about proportions, rate of change, and rate of growth are needed for a high school graduate to effectively use knowledge and tools from environmental science as an informed citizen in a democratic society? What are the quantitative reasoning stepping stones from elementary school through high school that might help develop this key to environmental science literacy? These questions are being addressed in the full richness of cultural relevance across our diverse nation in an NSF-supported project taking place at 4 LTER sites (SGS, KBS, SBC, BES) and a number of other sites in the US.