I can't give you many titles, most books I remember I read long ago(I read a lot as a kid, but at some point I wasn't able to concentrate on reading as well anymore). but I do reember various books with ecological themes, although they were all youth/children books.
the only one I remember the title of was the thule-trilogy, however I think that was written by a dutch author and I have no idea if there is an english translation. it is about a kind of post-nuclear war world, where there are 2 new nations: 2 very similar industrial nations, one consisting of mainland europe(mostly nuclear wateland, and that nation is warlike, focussed on conmquering resources, they rediscovered some technology like steam-warships powered by coal), the other conmsisting of the brittish islands, culturally/technologically very similar to mainland europe, but they managed to not get conquered by the nation controlling mainland europe.
and the third nation, Thule, located on greenland and not a nuclear wasteland, but a very fertile lush country(because of a changed global climate), with a pacifist matriarch society/culture.
the story is about the mainland europe-nation discovering greenland, and trying to conquer it. (and some of them discovering that Thule isn't that primitive after all, just culturally very different)
I also remember a book about a post-global-warming-flooding-world, where all people live on oil rigs since all land is flooded or inhabitable, and then some kid dives into a sunken town and reads about greenland/finds an old map, wich should be habitable because the ioce-sheet should have melted, so they set out to find greenland.
and one book, wich was not so much focussed on the ecological side but did happen in a postapolyptical world, where all cities where mobile, like giant cars, and cities hunted and ate eachother for their basic resources.
