Gulf Stream becomes confused

The main thing that keeps us Northern people warm are the giant oceanic plumes like the Gulf Stream.

We are lucky by plate tectonics that there is a perfect ramp with South America deflecting the warm water up to Britain.  We, in Canada, mainly benefit from the Gulf of Mexico and Pacific plumes.  For some reason, the Gulf Stream plume is confused and may not be working at full capacity.  There is a bit of a backwash.  In my fertile imagination, I think of the main equatorial current shifting a bit more south and missing the ramp completely.  That would be a true mini ice age for the North.

My working hypothesis is that we enter our Snowball Earth phase when all the continents are well separated.  At that point, the oceanic heat pumps work to dump heat towards the poles.  My problem is demonstrated here, in that an efficient heat pump like the Gulf Stream would make the Arctic warmer.  I can only conclude that all the heat is deflected to the south.

PS.  The Gulf of Mexico is heated by this current, as well.  Should it turn off, we would get continental glaciation up here in Canada.  It wouldn't be successful because the land is depressed by the last glaciation.  But in 5000 years, if it turns off, we get another ice age.  If the equatorial current dips below the South American prow, we would just get another mini-ice age.