I recently answered a question about finding spec fic markets responsive to stories with a “green message”. Here’s my answer, and it applies to stories with any kind of message — political, social, religious, sexual, even a rant against whoever canceled the latest Joss Whedon show.
I suggested two things:
First, you can search for appropriate markets for any spec fic story using http://www.duotrope.com/ or http://www.ralan.com/.
Second, generally speaking, all magazines are open to stories that have a green message (who doesn’t enjoy Kermit’s musings?), with the caveat that what magazines really care about is the story, not the message. You can have the most important message in the world, but if your story is a thinly veiled excuse just to deliver that message, or if you deliver it in a “As you know Bob, all the reefs died due to global warming and pollution.” “That’s right Ed, if only we had done X we would not now have to try to repopulate the oceans to prevent a catastrophic collapse of the food chain” manner, nobody is going to hear your message over their own groans.
But if you tell a gripping and moving story about your character, who just happens to be affected and their world shaped by whatever issue you are concerned with, if you let us experience first-hand the negatives you worry about rather than pointing them out to us, etcetera – in short, if you tell a dramatic story about a character we care about and sneak your message in like a message ninja – then really what you should be looking at is not magazines that support a green (or whatever) message, but rather the magazines that support stories of whatever sub-genre and length yours is.
Moreover, if you focus on magazines that are known for supporting green (or whatever) messages, well, you’ll be preaching to the choir anyway. So really, you should be looking for ways to get your message out to readers who don’t already know and agree with everything you’re likely to be wanting to share.
At least, that’s my experience/ impression/ knowledge bestowed upon me by the aliens who live in my sock drawer/ best advice.