Yeah, I wrote a paper on the breakdown of the thermohaline circulation system in 2003, it's not a new thing, but we had no idea when it would happen. Still don't really. When it does it's going to be bad for everyone. Without the poleward transfer of heat (which the seas do far more efficiently than our atmosphere), those at high latitudes will suffer much lower temperatures (it's worth noting that we are on a similar latitude to Moscow, but we don't suffer their winters because of the effect of the gulf stream), and those near the equator, where heat will just build up will cook.
If and when the system does break down, it will happen over years (possibly months) not decades because the freshwater blocking the movement of the 'conveyor' at the poles will just jam up the whole system.