Bill McKibben delivered a moving lecture and then took questions from the audience as the Sustainable Cities Conference kicks off at Washington University. http://www.350.org/en is a website associated with much of his work. A piece he wrote called Global Warming's Terrifying New Math went viral out of Rolling Stone Magazine this past summer. If you're not familiar with his his work, it is worth the effort.
The place was packed to the rafters by people of all ages. The big issues are carbon emissions and fossil fuel use. Check out the article and his website.