Surely, some of this is technically beyond the understanding of the younger ones, but if they aren't able to understand the science, they shouldn't be called upon to lobby for specific policy options. Beyond the science, children need to learn about decision making if they are to be thinking contributors to the activism network. They need to see why certain types of energy, for example, are preferred by consumers, even though some people feel they are sinister or wasteful. They need to understand what we give up when we pursue one course of action over another. Yet that perspective is a far cry from the litany of goods and evils in the environment.
Disposable diapers are bad, cloth diapers are good.
Landfills are bad, recycling is good. Automobiles are bad, bikes are good. Using teak or mahogany wood is good, using rainforest woods is bad. As an example of the teaching tools used to get these messages across, consider National Geographic's Wonders of Learning Kit. While students may be adept at describing the evils of planet Trashoid, few can satisfactorily tell you exactly why something is classified as an environmental good or bad.