The climate was far more extreme in the past than what AGW is expected to do. It doesn't matter. Climate change is expected to be a problem because of changes that are faster than humans and other species can adapt.
Having said that, nobody has any idea how much of a problem it'll be for humans or even if life will be better or worse than it already is. All we have is predictions of sea level, temperature, etc. that don't directly impact us.
That says nothing about how bad it will be. Almost all houses get destroyed on a similar time frame anyway simply because people don't want to keep using old houses. They're often only designed to last 50 years.
Having said that, nobody has any idea how much of a problem it'll be for humans or even if life will be better or worse than it already is. All we have is predictions of sea level, temperature, etc. that don't directly impact us.