Regarding Antarctica, I think that meltdown was first though, so make that "the other way around". Antarctica's meltdown happens first; kills almost everybody, and then the Lesser Dryas event happens, killing all the big game in America (but not Asia).
Good show Lesser Dryas. You rarely see such detailed selectivity in a Climate Adjustment.
This guy says the Younger Dryas was caused by a comet impact in North America.