A parody is a writing that imitates another writer’s style.  A parody usually over exaggerates the author’s style by using humor and satire. One way you could write a parody is to turn the setting and journey around.  Set up a new scenario.  What if all the cities survived, but everything else like nature, trees, and rivers were destroyed by something like global warming?  A character could leave a protected domed city and venture out into the wilderness to find what a forest use to be like or what a mountain really is.  Like John in the story, he could come upon new things that explain how the earth used to be. Perhaps the character could stumble upon a hidden valley where nature survived because the weather was “just right” for it to live.  The setting would be reversed—a character from a modern world would go back into the primitive past to learn about an environment that no longer exists. The satire or irony of the situation would be the same as in the story where an environment was destroyed because of the ignorance of man.  Throw in some humor, and you’ve got a parody!