1.The Sun will eventually die. This causes obvious problems to life on earth.
Yep. Humans will have to find other planets to inhabit. Or more likely, hollowed out asteroids. Hollow out the inside and live on the inner surface. The astroid is spun to create a simulated gravity.
2.Earth goes through cycles of large climate change over thousands of years , resulting in such drastic climatic conditions as ice ages.
Shouldn't be too hard to adapt to. If you were living forever I suspect this sort of thing would be a welcome change.
3.The gravity of the earth is gradually changing (Can't remember if its going up or down)either way this would change what kind of life can live on earth.(magnetic polls shift as well and reverse over time, I'm not sure what effect if any this has but I believe they are getting weaker which would have an effect.)I think you should check your notes on this one. The magnetic poles definitely shift around a lot (geological-time-ly speaking) but gravity is based on the mass of the earth which only increases extremely gradually. If the poles shifted or reversed today it would cause a lot of havoc technology wise, but future technologically advanced humans should be able to adapt.
4.Universe expanding , eventually stars too far away which would effect the gravitational pulls on our galaxy which could have big effects on our sun (if it was still there)in turn effecting the earth.Don't think this one is right either. The universe is expanding but that doesn't mean everything is uniformly moving away from everything else. Within our galaxy (which is not expanding) stars are moving in various directions. Even if the galaxy was expanding the gravity effects from other stars at this distance are so minute that the effect on us and our sun is negligible.
5.Meteorites and other space debris are a constant danger to the earth. One large impact could destroy much life.This sort of thing could wipe us out at any time. For an entertaining scifi read on this read Lucifer's Hammer by Larry Niven and Jerry Pournelle. Hopefully in the future this will be something that technogy can handle.
The one you forgot was #6. Heat death of the universe. When the universe reaches maximum entropy, that is, all of the heat energy is spread uniformly, no more 'work' is possible. (Work in the physics sense of a force moving thru a distance).. Past that point nothing is possible. Of course future discoveries could even solve this one.