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Comment by xyzzyz | Hacker News Reader

Ice age was not that much colder than now. Most of Canada was covered with ice, but most of United States wasn’t. Places which are hot today were warm at the time, and places that are warm were temperate. This means that there is no reason to assume that food was scarce.

Here is a way to think about it: Alaska today is probably colder than southeastern US was during ice age. Is food in Alaska so scarce today that it does not support megafauna? Obviously it’s not, quite the opposite. Same was true about most of US during last ice age.

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> Obviously it’s not

To be honest I don't think that's obvious to people who don't know much about Alaska.

I feel like you're understating it a bit; 20k years ago Manhattan was covered in over a thousand feet of ice. The Wisconsin Ice Sheet was huge and covered a substantial portion of the modern day United States: https://en.wikipedia.org/wiki/Wisconsin_glaciation#/media/Fi...

Correct, but this is more about the slow accumulation of snow, not all of which melts during summer. Over thousands of years, this leads to thousands of feet of packed snow.

The Mississippi must have been gigantic in summers when some of the glacier ice did melt.

The size of the river is related to the amount of ice that melts.

But the amount of ice that melts is completely unrelated to the amount of ice contained in the glacier.

On the other hand, the planet was only 4~4.5ºC cooler than at the beginning of the industrial area, so it was not that much cooler. For those who think that warming up the planet by 3 or 4ºC is not a big deal...

Was the whole planet 4-4.5 degrees cooler, or on average?

We are nowhere close to that kind of pace for temperature change. But it was that much warmer during several eras in the past, including the age of dinosaurs. Life arguably thrived even more under such conditions.

And, as always, the devil is in the rate of change. Living during slow changes is not hard but if the rate of change exceeds your ability to adapt, you are screwed.

I live on glacier shit (Long Island, New York). It's called a "terminal moraine"[0]. Cape Cod and Nantucket are also glacier poop.

Glaciers were huge. There's an xkcd that talks about that.[1]

[0] https://en.wikipedia.org/wiki/Terminal_moraine

[1] https://xkcd.com/1225/

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