Nobody knows whether that is really going to happen. We do not understand the Gulf Stream well enough to say how it will be affected. Last thing I heard is that it is unlikely to completely vanish. Besides, after the climate has changes enough, Labrador-like might not be so bad. In fact, the current models suggest that on a broad scale, there will be likely no place actually being cooler than it is right now. Global warming is still an apt description, it just neglects the other changes to climate that will follow.