James Verini has a very interesting nuanced profile of Fred Krupp, the controversial head of Environmental Defense, your neighborhood corporate-friendly environmental operation. Unfortunately, the article's only for subscribers, so you may need to rely on Dave Roberts' blog post instead:

You can probably guess my take. I value the person who moves a penny more than the person who talks about moving $100. Krupp has gotten lots of stuff done that otherwise wouldn't have gotten done. [...] The focus on motivations is a symptom of environmentalism's lamentable moralism on climate change. Krupp has moved a lot of pennies, so while I'm not going to put a poster of him up on my wall, I'm glad he's out there.

As I see it, it takes all kinds to change the world. As George Bernard Shaw said "all progress depends on the unreasonable man," but the specific way the progress tends to happen is that someone decides they want to step in and cut a deal with someone reasonable like Krupp. You need radicals and pragmatists alike for anything good to happen.