Ice Age Question for Climate Alarmists

• probably the most severe ice age of the last billion years occurred from 850 to 630 million years ago during the Cryogenian period
• it may have produced a Snowball Earth with glacial ice sheets reaching the equator
• a number of other ice ages have occurred on earth with glacial and interglacial periods

Questions for climate alarmists:

• What caused the warming that brought this massive ice age to an end?
• What caused the warming that brought an end to every ice age in the history of planet Earth?