In the historical record, since the Neolithic Period began 12,000 years ago, there has not been a major ice age. An ice age ended at that time and, in this interrum, humans have been able to develop everything from agriculture to ipads. There was a mini ice age that started during the European Renaissance and did not completely end until the 1800s.
Now, ask a geologist and they will list five glaciation periods. The first was the worst as far as I know and it occurred during the Proterozoic Eon when the only life on earth was green algae. The planet turned into a giant "snowball" and most of the life that did exist went extinct. Another such ice age occured millions of years later within the same Eon. After it ended, some complex organisms began to appear from among the surviving life. Subsequent ice ages in our current eon were not as bad as the first two, though they did cause mass extinctions that wiped about more than 90% of the species of animals on earth.