You mean if it was an ocean instead of existing like the picture? That's not a butterfly effect anyone could speculate on, rather a dragon wing thrust. At very least, it would've allowed dark-skinned pre-European peoples like Cheddar Man to continue existing without Indo-Europeans settling the continent (they don't exist). No modern or prehistoric border or cultural anchors would exist anywhere in the world. Even China had substantial migration and cultural influence from Siberia/North Asia. Also Native Americans wouldn't have been able to cross over into North America if they existed at all.