what would happen to the spirits if the earth got made unhabitable

[Cool101]

with spirits we know that they usually spend multiple lifetimes on the same planet but what if a nuclear war happened and made the earth uninhabitable what would happen would the spirits  mostly go to 1 planet and continue to achieve higher consciness there or would some spirits be forced to stay in the spirit world and evolve there so then they don't bring a planets consciness level down  because I know  higher consciness spirits are coming to earth and making the earth a higher consciness but would it be allowed for loads of lower consciness spirits to bring down the neutral consciness level of another host planet down

[Xanth]

They wouldn't exist here anymore.  Pretty simple really. 
There are an infinite number of realities for you to chose to be born into. 

[Szaxx]

If THIS earth was destroyed there's no problem with the possibility of going back in time and experiencing life then. Another thing to consider is this Earth, it may not be the only one. It feels like the only one as its your primary existence just being here. There's many other places just as real that you can travel to. The people there are the same every time you go unless you purposely travel at a different time period.