Accelerating with respect to what? That map makes it look like it's already happened. Oh look, I think I see Kevin Costner sailing by. You know, that map stretches linear distances in Antarctica by an unbelievable amount. If you wanted to walk along the coast between, say, the Amery Ice Shelf and the Ross Ice shelf (to pick a couple of easy landmarks), the round-earth model puts it at what, a few thousand miles? That map puts it closer to 25,000 miles. It should be pretty easy to prove to a Flat Earther which theory is correct, assuming he's willing to make a trip to the Antarctic. Charles Johnson isn't still alive anymore, is he?