I had two people in my critique group complain to me that the basic theme of my story has no basis in reality. I didn't really plan on everything being realistic. Plenty of sci-fi stories use insanely implausible plot devices. From what I've run across, the more people can understand some fictional thing the more they get upset over the plot holes. They have no problem with my story having humans create miniature stars as power sources for the ships, but they won't accept the problems I've created for the Earth's environment. I spent most of last night tracking down scientists working in the fields of geology and climate change, and sending them emails to get their opinions. The only real requirement to drive the story is a world where the Earth's human-friendly environment is collapsing, forcing the government to remove a large portion of the population from the Earth. The way the story is set up now, climate change has triggered the planet to go into an unstable period of tectonic shifts causing massive earthquakes, volcano eruptions, and floods. They intend on returning to Earth about 5000 years later after the unstable period has passed and the environment recovers. They argued that: 1) Climate change wouldn't cause this problem to begin with. (Although, I got the impression that the two people didn't really accept any climate change argument currently going on.) 2) Tectonic shifts happen over hundreds of thousands of years, not in compressed fifty-year blocks. (I have no idea what they meant by that. An earthquake is generally caused by some type of shift. My story is only saying that it's happening more frequently.) 3) They insisted it would take a million years for the Earth to recover from any sort of collapsed environment. I'm not sure how much the average reader would even care about any of this. The story is about the people living in this world, and plenty of fiction has impossible things happening. Any opinions?