Also, besides the RCA’s decision to endorse environmentalism, we have no one on record who says to watch out for the environment.
Another point to be made is that chazal speak openly about how dangerous things that are done by a large amount of people are not actually dangerous – this is based on shomer pesayim Hashem. To an uninitiated, if something is poisonous, then the alarm must be sounded – how can chazal let people do things that are sakanah!??!
The answer is that danger depends on how much Hashem makes something dangerous, like every other physical existence. Since a lot of people do something, the danger that scientifically would exist ceases to be effective, because like I said earlier, a person being damaged by, say, playing in traffic, is due not to being in traffic, but a punishment for violating the mitzvah of venishnartem.
When something is not done by a multitude, like meat and fish, the sakanah is there and if someone does it, there’s no shomer pesayim Hashem.
So too with environmentalism – even if we were to accept that there is a danger, we’d have a halachik device of shomer pesayim Hashem to rely on that there would not be any damage from, say driving our cars and so on.