For all intents and purposes the cyclic 11k - 13k year coming ice age has been predicted for a long time.
Global warming hasn't been incited as a cause and there are certainly more factors than the gulf stream to consider regarding an ice age.
The resulting change of an alleged discontinuation of the gulf stream is not limited an ice age.
Speculation is pure media fodder.
Considering that the CO2 is the basis of man made global warming and that CO2 is regarded by the same branch of Science to be a +ve feedback mechanism.
Why has it been shown that mean temperatures throughout geological history have remained consistently (apart from the cyclic ice ages)the same while a reduction in CO2 has has followed linear reduction from concentrations as high as 7000ppm and the fossil record has shown these to be times of prolific plant and animal diversity.
An ice age, if it were to occur would certainly tie up large quantities of the earths water in the newly formed ice fields thus making more land available as sea levels drop and change the face of all earths continents.
The redistribution of weight over land is also something that would need to be considered. Where billions of tons of water once existed for instance, if we are being hypothetical, would the land mass not rise due the the change in pressure differential and unpredictably change the face of landmass on earth.
The reality is that none of this is predictable, just guesswork.