I do not consider myself an extreme environmentalist, but I do believe we have a responsibility to protect and be good stewards of the planet. Part of standing up for injustice is standing up for the harm we are causing the environment. Part of the curse of sin was environmental, and the bible teaches that even creation groans for Christ to return so the earth will be redeemed (see Romans 8:22-23).
The problem is, at least at times, our evangelical eschatology makes us bad environmentalists. After all, I have heard evangelicals say, why protect the planet if the planet is one day going to be destroyed in judgment so a new heaven and a new earth can be created. That sentiment totally goes against all Jesus taught about the Kingdom of God and how we are to bring the Kingdom of God into our present, everyday lives.
My favorite hobby is scuba diving. I love the beauty and tranquility of the ocean. I love 
seafood. I love the connection I feel to God while swimming with some of the most fascinating creatures imaginable. It is for this reason that I am especially sad today to see what is happening in the Gulf of Mexico because of the BP oil spill. The eco system has been damaged and fish are now being caught with strange sores and sicknesses. (Here is a link to the news story.) May Almighty God forgive us because we really don’t know what we are doing. (Here is another link)
Floods of Justice 
Bravo Kevin, you hit the nail on the head. Just because Jesus will come someday doesn’t relieve us of our stewardship duties. Part of our judgment in the end will be based on how well we treated God’s creation. I don’t recall anything in Genesis about going ahead and exterminating anything we want. Our activities are wiping out species at unprecedented rates. This is especially the case among amphibians. Since they are closely tied to their aquatic habitats they are the first to show signs of environmental stress and are the first to die when their environment begins to change.
Jeff,
I will never forget a talk I heard by a TN Wildlife Game official talking about the importance of mussells in our rivers and streams in TN. When the mussell population decreases or disappears all together that is a sign of an unhealthy or dead stream and bad water. This particular official was concerned about the decrease of mussells in our streams and rivers.