>> No one knows the amount of thought I put into this same problem when building train tracks for my son but I had no idea how to solve the problem.

My opinion is that it will rise until we reach a tipping point where changes happen that will lead to the next glaciation. IMHO there will be at least a few years where odd things happen and then the modeling folks will say "oh crap this is going to happen". Stalling of the north Atlantic current is just one of these things that might happen.

In this light, I don't consider human-induced warming a fundamentally new problem, but an acceleration of a process that has been happening for several million years. Not that it makes too much difference - I don't want a glacier in my back yard any more than I want the other outcomes people talk about ;-)