LowDown is closest to the truth.
90% of Earth ice on land mass Antarctica
7% of Earth ice on land mass Greenland
97% of Earth's ice is on the two land masses closest to an Earth pole.
And land moves....
During Jurassic and other "warm" periods, Earth had two polar oceans, resulting in an Earth with either no or almost no ice.
Think of Earth's climate as a room with two air conditioning units - Arctic and Antarctic - each with settings 0=off and 10=maxCOOL. Right now, due to the position of land, the Arctic AC is set at 1, and the Antarctic is set at 9. That is what controls Earth's climate. 99% of Earth climate change is where land is.
Now, more fun.
1 million years ago, Greenland was completely green, and North America was covered with ice age glacier down to Indiana...
https://www.livescience.com/7331-ancient-greenland-green.html
"The oldest ever recovered DNA samples have been collected from under more than a mile of Greenland ice, and their analysis suggests the island was much warmer during the last Ice Age than previously thought.
The DNA is proof that sometime between 450,000 and 800,000 years ago, much of Greenland was especially green and covered in a boreal forest that was home to alder, spruce and pine trees, as well as insects such as butterflies and beetles."
and these show where the NA ice was then....
https://www.google.com/search?q=nor..._AUICigB&biw=1440&bih=786&safe=active&ssui=on
So, during the past million years, Greenland froze while North America thawed, all at the same time on the same planet with the same atmosphere with the same amount of CO2 in the atmosphere.
So what caused it, given that CO2 and the atmosphere did NOT???
Greenland's plate is moving NW, NA's plate is moving SW....
As a land mass gets closer and closer to an Earth pole, the winters get longer and colder, summers shorter.... and eventually the summer fails to melt all the snow... which then starts a STACKING PROCESS.... which is the start of an ICE AGE.... which is CONTINENT SPECIFIC, not planetary, as one continent froze and the other thawed right next to each other....
There, have some new insight and ponder....