Other than that, there’s various other lumper-splitter positions. Africa is almost always considered a separate continent, but, historically, the Mediterranean has had periods of being mostly dry and there’s the Suez in any case, which links it to That Massive Landmass What Most People Live On. To take a different tack, India is often referred to as a subcontinent, or The Subcontinent, and just splitting it out into the Indian Continent with the Himalayas as a dividing line would make more sense than pretending the Urals form an impenetrable barrier. That plan would also make Asia impeccable.
Similarly, there’s the division line between North and South America, or you can decline to split them and refer, indifferently, to The Americas or The New World. If you’re a splitter, you can talk about Central America, which is usually not a continent or a subcontinent or a Subcontinent, but instead a “region” or similar, and debate whether it includes Mexico, or whether it would include Colombia had history gone differently.
Mercator gets the blame for making people think Greenland should be a continent, but having Oceania instead of Australia is a bit omnium-gatherum for my tastes, grabbing a bunch of the South Pacific and breaking the notion that continents are at least somewhat unified landmasses.
Meanwhile, the geologists are all off studying the real movers and shakers, and dividing up the world along the real dividing lines, mostly hidden from view.
There have, in fact, been multiple discrete times when all or almost all of the continents have been joined. Pangaea was the most recent, but before that there was Gondwanaland, and there were others before that, too.
EDIT:
But Oceania is in fact a somewhat unified landmass. All of those little islands are on the same plate as Australia.
If we define continents by plates, we’ll have to split and merge a lot of landmasses which are pretty unambiguously continents to most people. After all, humans somehow managed to avoid drawing our political-cultural lines along the most recent set of major crustal fragmentation lines, and the oceans don’t necessarily respect them, either.
The definition of ‘continent’ is like the definition of ‘planet’: Tantalizingly simple and within your grasp until you look more closely at any given definition and what it includes and excludes, at which point it dances away to just out of your reach. At least with ‘planet’, you can kind of punt and reframe the classification into rockball/iceball/gasball, and then grade gasballs by how hot they are, whereas once you abandon the notion of continent you end up with less-satisfying categories like ‘landmass’ and ‘region’.
Where the two oceans meet (Cape Agulhas, true southern tip of Africa) and where the two currents intersect (usually located more-or-less off Cape Point, where a lot more tourists end up, mistakenly thinking it’s the southernmost tip) are two entirely different places, 4 hours car drive apart.
There’s no distinct change at Agulhas, it’s one continuous vista.
I gather that the term “Southern Ocean” as above, has been widely in unofficial use for a very long time – even if long rejected in official terms (the abovementioned 1953 IHO document stipulates no “Southern Ocean”, and emphasises Atlantic / Pacific / Indian as going right down south to Antarctica). I recall from Eric Newby’s book The Last Grain Race, recounting his experiences as a crew member in 1938 / 39 on one of the then few remaining big commercial sailing ships, making a return voyage Britain – South Australia: frequent references by the ship’s company to the “Southern Ocean”, in which they spent much time.
Not quite. His title was almirante de la mar océana: each océano is the pieces we call Ocean, but la mar océana is one of several expressions meaning all the seas of the world, (f) because that’s how sailors personify her. Los siete mares (the seven seas), el océano with no further specification, los mares (the seas), el mar or la mar (the sea)… also mean the whole of the world’s salty waters.
IHO adopted Southern Ocean (as opposed to Antarctic Ocean) by responding majority vote in the 2002 draft delineation, but that’s never been formally published - although the hold-up is more about picayune shit like the Sea of Japan, not the Southern Ocean itself (Australia’s fucked-up idiosyncratic definitionnotwithstanding), so I think we could say it’s as close to official as we need, as several organizations use that definition as a de facto standard, and more are catching on every year.
Well, to an extent. Some people might call one point the boundary between oceans, and some might call it some other point, perhaps as much as a few hundred miles away. But in almost all cases, that’s only going to affect a little bit at the end of the divide: Most of it will still be in the same place.
And that’s just for the ocean divides, too. Some divides are defined in terms of rivers (like the Great Lakes/Mississippi divide that runs through Akron, OH), and those don’t have that same sort of ambiguity at all.
I don’t think that there’s any reasonable definition of the ocean boundaries that changes the location of any portion of any continental divide within the US by so much as an inch.
don’t you remember when your mother asked you to wash the dishes after dinner in the evenings … you poured liquid soap into the plugged sink and cascaded warm water until enough had amassed. at top of the water was a bunch of suds … all in one neat mass. over five/ten minute period … that single mass broke down into multiple smaller masses.
think of the masses of suds as continents … and clear water regions as ocean. suds (tectonic plates) are never static.