They won't ever reach it.
Who cares, humanity will be extinct within a few hundred years anyway.
Man, you're optimistic. I give us until 2012 and then, as Bucky Fuller said, it'll be Utopia or Obliviion.
The 2012 thing is no different than the milennium bug of 1999/2000, smoke and mirrors and pure unadulterated BS. I have the book about "doomsday" 2012 and am eagerly looking forward to a book bonfire Jan. 1 2013. As for Bucky Fuller, I don't know who he is and I fully expect we'll be on the edge of oblivion at least after my daughter's time has passed.
After that, any possible descendants of mine are on their own!