All types of environmental discussions and opinions are accepted. Even non mainstream and revisionist works. If you can tie the post to the environment, global warming and the existential threat of climate change you're fine.

Sub-reddit rules:

Rule: Do not post insults or ad hominem attacks! No name calling! In Reddit's "Reddiquette" this is called "remember the human." In normal conversation it's called "don't be a dick." You're talking to another human -- be civil.
Rule: Stick to the sub's topic. The focus of this sub is "the environment" -- a broad topic. But please keep posts related to this.
Behavior: Try not to downvote. That gives a sub a "negative" flavor. This is a bit different than Reddit's standard advice, but it works. Instead of downvoting, don't vote at all on some post -- "deafen" them with silence. But by all means, do not downvote just because you disagree with someone no matter how much of a twit or fool the person is. Ignore the fool and avoid negativity.
Behavior: Upvote early and often. There can hardly be a thing of too many upvotes -- upvotes are positivity and happiness. And you have an unlimited supply of them on Reddit. So use them!
Expectation: Expect some biased or unconventional article sources. An intelligent, informed person should know the positions and perspectives of multiple points of view. Knowing what "the other side" or other ideologies arguments and perspectives are is important.
Behavior: Avoid editorializing headlines. Try to keep headlines as article titles or objective summaries about what the article's about. Comments are the place for opinions and editorializing.

Alternatives to Reddit's main sub-reddits:
/r/Business2
/r/Economics2
/r/Education2
/r/Energy2
/r/Environment2
/r/Health2
/r/History2
/r/Politics2
/r/Science2
/r/Technology2
/r/Worldnews2
/r/WTF2
/r/WorldPolitics2