Monday, November 11, 2019
Ice Age Physics -- Part 6
That's a nice picture. The seasonal ice fills both projections. Antartica and Greenland are held up (mountains) by hot mantle. If we had Antarctica on the North Pole, we'd be looking at giant ice sheets all the time in Toronto. We do not deserve to be warm, it is blind luck.
So, two million years ago it became cold enough for continental glaciation. It became cold because the main heater (thermal insulation) got turned off. We don't have continuous glaciers threatening to crunch all our condo towers, however, because the North Pole is over cold mantle.
This what happens with a northern ice advance. We go into a Little Ice Age every 600 years or so. That's cold enough to start, but all our northern continents are depressed from the last ice age. That's called Isostatic depression and uplift. Like a big sponge rubber ball.
Now, 5,000 years from now, all those continents will have sprung back to full height. A little ice age starts (like we are going into now), and ice builds up. It starts with the Arctic ocean becoming completely frozen for the year. Soon, the snow on the highlands doesn't melt in the summer. We have a full Greenland (and Antarctica) ice lock. The white ice reflects the Sun, and the tropical plumes cannot penetrate. The ice builds up.
We all go live underground and play on the ice sheets. Yeah!
10,000 years later, all the continents have sunk below sea level and the ice melts. The mammoths die off again, and we come out.