Already shared by others, but definitely worth a read if you haven't already: http://www.treehugger.com/culture/conservation-photography-and-necessary-evils.html
A few thoughts:
1) Morgan Heim's comments in this article are dead-on.
2) The author is too dismissive of the opposing viewpoint. While I think conservation photographers have a strong sense that the good they're doing outweighs the "necessary evils" like a high carbon footprint (and I have a feeling they're right), I don't think nearly enough work has been done to evaluate the impact of conservation photography projects.
So, does an activity like conservation photography really have a net positive impact on the environment? I suspect it does, but I don't think we have the data to show that conclusively. The NSF now demands a formal evaluation be built in to every science outreach grant they award... Perhaps all of the organizations commissioning conservation media should be doing the same. Yes, evaluation costs money. But in the long run, solid metrics of impact in environmental messaging, ideally shared among organizations, can advance the practice of environmental communication for everyone's good.