Great story, great discussion.
Is the narrator unreliable?
Is she playing loose with the truth as she tells her story to the people on the Ring? I'm not so sure that the audience for this story is the people on the Ring, as I got the impression her audience was as naive about the Ring and the sky people as they were about her and her people. Also, I would think her greater knowledge of the Ring and the sky people after living with them would inform her views of them, even if it only showed through phrases such as "At the time I thought sky people were...". Finally, if knowing the intended audience of the narrator's story was critical to the story, the author could have easily made it more apparent who the intended audience was. As it is, this story could as easily be an entry in her memoirs, intended for her great, great grandchildren, as a story told to people on the Ring.
She is an unreliabe narrator in the sense that she is telling what happened as she saw it, not as some sort of omniscient being or objective observer simply relating the facts of what happened. Do her personality traits and cultural beliefs make her less reliable than most others? That is, is her version of events further from 'the truth' than most other versions would be? Or is she the most reliable narrator possible under the circumstances? As others have already addressed these questions, I won't say more about them here, except to ask a question - does disliking the narrator lead to a greater belief that her narration is unreliable? True, one could argue that the same traits which lead to a dislike of the narrator also diminish her reliability, but do they? Her tendency to point out other's faults and her own strengths, as she sees them, does not mean that she is making up these faults, or her strengths. While I take her characterizations of others and her suppositions about their motives with a grain of salt, I don't have cause to think that she is a pathological lair or has reconstructed events to fit her perception of herself or others. [Then again, I didn't personally dislike her, either].
Is the message of this story that nature is good and science is bad? I don't think so. Certainly there is the message that science often has dire, unintended consequences, and we are arrogant if we think otherwise. But it is science after all that has preserved some nature from earth on the Ring, and science that has preserved the human race, even if it was science that polluted the earth to start with [or our use of science, at least]. And I wonder if the real message here isn't that human beings simply can't accept things the way they are, without attempting to change them to suit our needs. The complicity of at least some of the people of the earth, people who had sworn to change themselves rather than change the earth, in the sky people's plans speaks to this. The people of the earth weren't even agreeing to change the environment in a way that would have significant effects on their ability to survive, only to change the sky back to the blue they were used to. We are tinkerers at heart, and having discovered science we can't go back in time and live the idealized life of the noble savage, at one with nature. And while we could learn some things from the wisdom of those who lived closer to nature, our future is with science, in the stars.
But the more I think about it, the more I think the the science/nature conflict is more of a setting for this story than a message, that the interaction between the peoples of different cultures is what really counts here. If the author had a specific message she wanted to communicate, I think Etherius probably comes closest when s/he wrote:
"The "deeper message" of the story, I think, is not that science is bad or evil, but that acting and judging rashly and out of ignorance is bad. The narrator and her people pre-judged the sky people as being all cut from the same cloth, and by the end of the story she realizes her judgment was not entirely fair. The sky people presume that they understand what is going on down on the planet, and the "earth people" are too proud of their perceived moral superiority to explain their perspective to the sky people. If the two sides had been willing to open a dialogue about what was going on, the sky people might have seen the signs of intelligence in the cloud dragon phenomenon, and the "earth people" might have won allies instead of alienating the sky people to the point where they just did what they had planned to do anyway. It's a lack of mutual understanding and a sense of false pride that dooms both sides; the only people who survive the disaster are the two who made the effort to reach out and meet each other halfway, fumbling though their efforts were."
Whew! Sorry for the long post.