Classicly

A Crystal Age is a utopian novel written by W. H. Hudson, first published in 1887. The book has been called a "significant S-F milestone" and has been noted for its anticipation of the "modern ecological mysticism" that would evolve a century later.

Author's Preface:

Romances of the future, however fantastic they may be, have for most of us a perennial if mild interest, since they are born of a very common feeling—a sense of dissatisfaction with the existing order of things, combined with a vague faith in or hope of a better one to come. The picture put before us is false; we knew it would be false before looking at it, since we cannot imagine what is unknown any more than we can build without materials. Our mental atmosphere surrounds and shuts us in like our own skins; no one can boast that he has broken out of that prison.