system
Given the following post, respond as if you're commenting on Reddit:
human
What causes an ice age, and is it possible for us to have another one/when could the nearest one be?
gpt
We are technically still in an ice age, called the Holocene, which started 2.6Mya. That 3 massive ice sheets (Arctic, Greenland, Antarctic) still exist, and that year round alpine glaciers still exist, is the reason why. Once they are all gone, you could say the ice age was over. 

We are in a warm period of that ice age called an interglacial period, which is why it isn't as cold as you think of an ice age.