I've always liked this flier too. Anyway, remediation and decommissioning of brownfield sites definitely seems a career that people here should probably consider. I, for one, plan on using my degree in environmental engineering to do exactly this sort of work, or perhaps work on environmental emergencies (Gulf oil disaster, groundwater contamination, etc.). All environmental disasters from anthropogenic sources can be attributed to these disasters being extraneous: when determining whether a project should be undergone, the costs associated with disasters are not considered, as the chances of them occurring are low and far into the future (time value of money).
A documentary relevant to everyone's interests: Life After People (2008). You can probably watch it on Google Video.