The onset of ice ages is relatively slow - the last ice age took about 10,000 years from its onset to reach the peak of of the ice sheets, and another 10,000 ye

The onset of ice ages is relatively slow - the last ice age took about 10,000 years from its onset to reach the peak of of the ice sheets, and another 10,000 years or so for the ice age to end. At the glacial maximum average global temperatures were about 6°C colder than today, and we've managed to raise temperatures by 1°C in only 100 years. Changes at the speed of man-made global warming (or faster) do happen, but they are uncommon and tend to be associated with catastrophic events and mass extinctions.