How Many Continents Are There?

Nailing down what makes a continent a continent is a surprisingly tricky business. Learn more about how we humans have defined landmasses, past and present, in this episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff production of iHeart Radio. Hey brain Stuff,
Lauren Vogelbaum. Here in elementary school, we learn some indisputable
fundamental facts. Two plus two equals four. The world's round.
There are seven continents on Earth, but that last one
isn't quite so cut and dried. Here in the United States,

(00:24):
students learned that there are seven continents North America, South America, Europe, Asia, Africa, Australia,
and Antarctica. But that's hardly the last word on the matter.
And much of Europe students learned that there are six
continents Africa, America, Antarctica, Asia, Australia's slash Oceania, and Europe.

(00:44):
There's a five continent model which lists Africa, Europe, Asia, America,
and Oceanica slash Australia. And that's, by the way, why
there are five rings on the Olympic flag. And some
experts think that four is the way to go, using
as their criteria land masses now truly separated by water
rather than man made canals, so Afro, Eurasia, America, Antarctica,

(01:06):
and Australia. As recently as the eighteen hundreds, some people
said that there were just two continents, the old including Europe, Africa,
and Asia, and the new encompassing North and South America.
So what really makes a continent a continent? We spoke
via email with Dan Montello, a geography professor at the

(01:27):
University of California, Santa Barbara. He said, nothing really determines
a continent except historical convention, a bit of an overstatement
but mostly valid. Certain factors make a landmass more or
less likely to be called a continent at various times
in history by various people, but nothing can be said
to determine continentality in a completely principled, non arbitrary way. Take,

(01:51):
for example, the vast country of Russia six point six
million square miles or seventeen million square kilometers. Why has
it often been counted as part of you up rather
than Asia? Montello explained. The Ural Mountains are taken to
separate Asia and Europe, but only because Russians wanted their
great city of Moscow to be European, so the Urals

(02:12):
were a convenient marker for that arbitrary decision. Continents are
mostly spatially contiguous collections of land masses larger than countries
but smaller than hemispheres. Of course, continents do not necessarily
fit entirely within single Earth hemispheres and thus cannot be
defined by ranges of latitude or longitude. Okay, so how

(02:32):
about plate tectonics. If certain land masses are constrained to
one of those massive shifting hulks, can we safely call
it a continent? Montello says, no quote. Plate tectonics has
nothing to do with it historically, and it certainly could
not provide a principal basis for continents. Now, nearly every
continent includes parts of multiple plates, the same those for climate.

(02:55):
After all, continents contain multiple climates, as evidenced by Alaska's
arctic chill compared with Florida's humid heat. They're both part
of North America. Mountain ranges and coastlines are useless too,
as our culture and politics, Montella said. Neither ethnicity, race, culture,
nor politics has ever defined continents, except by conventional theories

(03:17):
that were largely mythical, such as old and fallacious ideas
about correspondences between races and continents. Politically, Hawaii is part
of the US, but is in Oceania rather than North America.
Greenland is controlled by Denmark for now, but is considered
part of the North American continent. So really it boils
down to whom and when you ask, Montello said, no

(03:40):
one can say, as a matter of principled fact, how
many continents there are, because the decisions are largely based
on convention, and convention that goes in and out of
fashion over time and is still debated today. He concedes
that these days many geographers would opt for a list
of seven continents Africa, Antarctica, Asia, You're up, North America, Oceania,

(04:01):
and South America, but he added that some of them
would combine Asia and Europe into Eurasia, identify Oceania in
other ways, or combine North and South America into the America's.
He said, there is simply no BZAR or CEO of
continents or any other ultimate authority, so it's pretentious for
anyone to claim that they have the authoritative answer. But

(04:26):
don't worry if you can't handle that kind of definition.
It's all changing. The continents are drifting at a rate
of about an inch or two point five centimeters per year.
Today's episode was written by Nathan Chandler and produced by
Tyler Clang. For more in this lots of other topics.
Visit how stuff works dot com. Brain Stuff is production

(04:47):
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