National Parks and Sustainability
Have you ever spent any time at the Park Service's web site? I mean really spent some time darting into all the various worm holes that lead to fascinating places? You could easily kill the bulk of a day scrounging around the site.
So let me make it a little easier for you. If you're interested in sustainability and curious about what the Park Service is doing to promote it across the national park system, check out this site. Some time spent there will bring you up to date on a range of projects different parks are implementing to be lighter on the land...and air...and water.
There's also pretty good information on climate change and what it means to the parks. Definitely a good site to bookmark and check from time to time.