What are Continents?

How many continents are there? If you grew up in the English-speaking world, you might think that the answer is obvious: 1, 2, 3, 4, 5, 6, 7. But not everyone counts continents the same way. The usual definition, that they’re large land masses separated from others by oceans, is fine, until you actually start to think about it, and then you run into problems. Problems, like this: Here’s Europe, here’s Asia, and you’ll notice the lack of ocean between them. Why then, are they two different continents?

The usual reason for this split is a cultural one: that Europe is so different from Asia that it’s best to pretend it’s a separate entity. OK... maybe. But if the cultural argument is valid, then surely it also applies to India and the Middle East. Now you have nine continents and a new problem: if culture defines continents, then you’ll never stop drawing increasingly unhelpful lines. So some places ditch the culture division and combine Europe and Asia into Eurasia. This Eurasia is not to be confused with this Eurasia, which has always been at war with Eastasia. Making Eurasia gives a six-continent view of the world.

But what about over here: North America and South America? They’re connected at Panama – or at least they were until Teddy Roosevelt decided that someone had to cut that country in half and it might as well be him. But even still, the Canal is only 13 meters deep. You could walk all the way from Northern Alaska across the narrow Panama Canal and, if it weren’t for the deadly, impenetrable, poison-filled Brazilian rainforest, make it all the way to the southern tip of Chile. So North and South America, despite the canal, aren’t really divided.

Which is why some places, particularly South America, treat America as a single continent, not two. Which brings the total number of continents down to five. But... if you discard the Panama Canal, then you also have to discard the Suez Canal, and you’ve just created the monstrously large Afro-Eurasian continent: 85 million square kilometers home to 5.7 billion people. With this four-continent view of the world, we must be done because there are no more continents to merge, and our definition from the beginning is now consistent.

Except we’re not done because of that troublesome word 'large'. Exactly how large is continental large? Is Australia really a dinky continent, or is it the king of the Islands? Why not make Greenland the smallest continent? It’s pretty big, even if you took away its ice. And speaking of ice, what about Antarctica? The forgotten continent, unfairly smushed against the bottom of maps just because no one lives there. Remove the ice sheet that covers Antarctica, and you reveal it for the archipelago it really is, not the single land mass it pretends to be. And, to complicate matters, the largest of these Antarctic islands is smaller than Australia.

So if you want to keep calling Antarctica a continent, then there’s a bunch of other islands that might want to be continents too. Islands like New Guinea, Borneo, Madagascar, Baffin Island, Sumatra, and Honshu. While this seems inclusive to the point of silliness, ultimately someone has to decide what ‘large’ means, and that’s going to be an arbitrary line. This problem will be familiar to anyone who remembers the is-Pluto-a-planet-or-not-a-planet fiasco, which hinged—mostly—on this same issue of size.

So now we’re more confused than before we started: there might be three continents or dozens. You know what will sort this out: SCIENCE! Confusion + science = answers. Let’s ask a geologist what a continent is. For them, a continent is a tectonic plate: parts of the Earth’s crust that move together.

So, geologists, show us your continents. The Antarctic plate, the Australian plate, the Eurasian plate, the South American plate, the African plate. So far, this looks pretty good. The... Middle Eastern plate. The... Indian plate. The Caribbean plate? The Pacific plate? Well, there isn’t even anything there. Well, there’s mostly nothing there. The Nazca plate? The Scotia plate? Really? At least North America is still looking reasonable. Until you include a chunk of Russia, and half of Japan, and half of Iceland!

Well, this is unhelpful—thanks a lot, geologists. The heart of the problem is that the word 'continent' doesn’t have a simple and consistent definition for everyday use. So how many continents are there? Well, how many do you want there to be? Six. The answer is clearly six.