Well, I have done it. I've found a YA novel with an environmental setting and secondary story line that is not climate fiction or post-apocalyptic or dystopian.
What Kissing Frogs by Alisha Sevigny is, is a YA romance. That is a genre I do not embrace. But main character Jessica is sharper than the romance main characters I've encountered in the past. Seriously. She is smart. She's maintained an A-average across the board while using her brain power to make herself a member of a popular-girl group and snatch one of those shallow, good-looking guys who are never up to any good.
She blows her biology grade, though, which is how she ends up in Panama with a science club from her school that is volunteering to work with an endangered frog species. Her biology teacher is their faculty adviser and offers her the opportunity to take the trip and write a paper to save her average and her chances of getting into UCLA. Some may find that a bit of a stretch, but I find a lot of things that happen in romances a bit of a stretch.
Kissing Frogs is a fish-out-of-water story. Jessica is the outsider with this group, though she's smart enough to be one of them. With this crowd, she becomes the victim of science mean girls, mean girls who had been victims of members of Jessica's posse back at school. That's a neat little twist. There is a bit of a torn-between-two-lovers thing going on, something I always dislike. In this case, though, one of our potential lovers is clearly a player, and Jessica knows it...because, remember, she's smart. She's also no damsel in distress.
The environmental story-line involves the Panamanian golden frog. The Final Wave of the Panamanian Golden Frog at The Guardian suggests Sevigny did a fine job with her factual material. She also does one of the best jobs of integrating environmental information into a main story that I can recall seeing. I won't say there was never a moment when I felt the characters were being just a little over informative. But there was also never a moment when I felt a character was saying the equivalent of "Let's save a species!" either.
Environmental material is going to get out to a lot more people when it can be packaged in main stream books like Kissing Frogs and not just be isolated in disaster stories.
Another interesting thing about Kissing Frogs--it's published by Swoon Romance, which is a "digital-first" imprint. Kissing Frogs exists in an eBook edition only. That might limit its audience, which would be too bad. I don't know how popular eBooks are with teen readers.
On the other hand, if you have a Kindle, Kissing Frogs is only 99 cents.