Applying environmentalist risk assessment methods to the Iraq issue gives you some clues about why you shouldn't trust them on the environment. Of course, they don't do that, generally opposing any military involvement anywhere.

Saddam is also a criminal against the environment. Remember his setting Kuwait's oil fields on fire? The gassing of the Kurds did permanent damage to their soil as well as their gene pool. What would his nukes do the environment, if he gets them? Yet environmentalists almost uniformly oppose efforts to rid the world of him.