The last of the six ice ages Earth experienced is the Quarternary, lasting the prior 2.58 million years. Understand what an ice age is – a period in which the poles have ice caps, not a period when we see glaciers in temperate latitudes. Those are stadials, and the last time we had those glaciers was during the Younger Dryas, which ended about 12,000 years ago. One of the periodic ice sheets in North America was the Laurentide.
This five hundred meter thick sheet has just three centuries left at our current 400 ppm of CO2.
I wonder if that last little patch of ice will be a redoubt for reindeer or polar bear/grizzly hybrids, the way Wrangel Island was for the mammoths. That’s ten generations in our future, but it’s the blink of an eye in geological terms.
There are a variety of markers that are cited as the start of the Anthropocene, often the radionuclides from the Trinity test in 1945 being the first solid entry in the geological record. The lost of this last bit of the Laurentide will surely be an important milestone in the early centuries of this fearsome new age.