From my recollections, the famines happened when it cooled down. Suddenly growing seasons weren't warm or long enough to sustain the food crops of the time.
What would those be based on? In the winters that we have now and have had in the 'recent' past does the American Southwest get more rain than it does in winter months?
The climate models that are animated used a map of the earth but when the white ice moves down from the north the map keeps the desert regions the same shape and size but reality shows that when winter comes along and the snow moves south the desert regions shrink and the moisture falls the land then turns green. That change would be gradual over 1,000's of years before it stabilized into a system that delivered the same stable weather for a few 100,000 years.
Since the desert regions recede and they can support two crops per year you would have to lose 2x as much farmland to the frost before 'ice-age conditions' are 'worse'. What would be worse is having it com on a society that does not know what is going on and how to minimize the impact on Society. Move from the frost to where the rain is starting to fall, any other option will lead to you becoming extinct.
Today when people get in close proximity they fight, in an era where the weather puts you in close proximity and food is abundant it works out for the various parties if they co-op on projects. If you want some 'new recollections' lets try that weather model and rewind time a few ice-ages and promote that as the source for the 'advanced civilizations' that 'vanished' when the culprit was and end to an era that would see the 'food belt' of the world turn to dust in a remarkably short period of time. The 'survivors' now had to fight for food or die and that would have been the first and biggest change and the next one was the gap the desert region caused as far as working with your neighbors.
Do I have any links, no, does that make the climate change model inaccurate, no as the model is based on observations that are called 'records', especially the differences between summer and winter in North America in the present and near future and the far future. The 'slo-mo' version would see the 12 month winters start in the east and gradually work their way across the land until they reached the Pacific Ocean. That is what the stable weather pattern would be based on and the cold water going into the Pacific might have been enough to cool the hot water that was driving the perpetual winter model and the w-e winds began to blow again and that is what broke the last ice cycle 15,000 years ago.
Some of the math that the last ice-age was based on the current oceans were smaller in the past 200M years. If you were to try and model the weather that far back as far as ice-ages go you would have to allow the flooding of the existing dry land as the existing ocean basins sunk back into the rifts they originally came from. The Pacific Rift originally started out at the AB/BC border and erosion is said to have worn down a mile or so of the 'original Rockies' during their creation and the migration of the rift to where it is now. The reason for doing that is at the present height they would almost be totally covered by the 'rising ocean'.
With the ocean crustal plates removed and the land areas joined to create a new, smaller, globe with the same amount of water and 'air' that we have today the ocean level would be a certain height higher than it is today and the air pressure at 'sea level' would also be higher so the creature alive at that time would take advantage of both of those conditions.
How much would the drop of 400 ft cause on a globe the size of the one we have today? (for plants in a CO2 rich and thicker atmosphere 200M years ago you would have to remove 12,000 miles from the present day circumference so that would almost double the amount of air pressure and more food would mean the O2 breathing creatures of the day would have double what we have available today.) If more plants exist in the inhabitable parts of the earth during an ice-age the O2 content should be a tad higher, same as if you lived in the Amazon compared to Arizona today.