/sci/ - Science & Math

>>10182763
Actual climate scientist here, I study atmospheric gases in ice core.

We know quite well the mechanisms and nuts and bolts of the last deglaciation. It started with the Milankovitch cycle (https://en.wikipedia.org/wiki/Milankovitch_cycles)) the amount of solar radiation and the seasonality of the earth changes because the earth's orbit stretches and wane due to gravitational pulls from other planets. At 18ka, solar insolation in the northern hemisphere started to ramp up (2nd figure from top). This causes the North American ice sheets to melt. Addition of saltwater destabilizes the thermohaline circulation https://en.wikipedia.org/wiki/Thermohaline_circulation that is driven by sinking cold salty water in the north atlantic. The destabilization of thermohaline circulation causes Antarctica to warm (not plotted, but you can find any ice core temp record from antarctica it looks like CO2). Think about it as the ocean current being a liquid cooling on CPU that is Antarctica. Distruption of the thermohaline circulation causes heat to build up in Antarctica. Heat build up melt away sea ice, intensify the Antarctic circumpolar circulation and allow CO2 from the deep ocean to exhale back to atmosphere (green figure on the left). CO2 from the southern ocean causes global warming and brought the whole planet out of the ice age.

What >>10182774 is talking about is the sudden reversal at the onset of Younger Dryas. Other deglaciation along the Milankovitch cycle did not have a reversal, so the YD reversal and snap back might be related to short term cooling due to asteroid