Datavisualization
Environmental issues are interdisciplinary and wickedly complex. Fortunately, following the lead of Doug Engelbart, we have better tools for seeing order and solutions.
General
http://www.visualizing.org/visualizations Visualizing.org].
http://www.ted.com/talks/eric_berlow_how_complexity_leads_to_simplicity.html Eric Berlow (TEDtalk video).
Simon Shum at Open University in the UK creates amazing tools.
Care2 gives various kinds of eco and demographic info based on geography.
If the world's population lived in one city (different densities).