There is nothing wrong with being concerned with the environment. My problem with so-called environmentalists is when they place the concerns of the environment before the concerns of man, and as Binyamin suggests they end up worshiping 'mother nature' and all other forms of idolatry.
Judaism is very concerned with preserving the environment. Many commandments relate to the need to respect the planet including laws concerning preventing damage to trees during wars, protecting the safety of animals, not polluting the water and air, and many others.
But what is essential in all of this is to acknowledge that we have the power to affect our environment, and we should use this power for the good and not for the bad. Shabbat shows us that there is a time for creative energy, and a time to rest from it.