Why is Greenland considered an island but not Eurasia?

As far as New Zealand goes, current thinking is that it is indeed part of a continent: Zealandia

That’s quite wrong. No Panamanian would say that. Latin Americans and many Europeans consider the Americas to comprise a single continent, rather than to be divided into two. Panamanians who live on either side of the canal certainly don’t consider themselves to live on different continents.

Geologically speaking, Costa Rica and Panama originally comprised a separate island arc that formed between North and South America, and so technically belong to neither. However, they became attached to North America as a peninsula long before they collided with South America. And northwestern Colombia is actually part of of that same geological structure, and so if one demarcated the boundary between North and South America geologically then that area would best be considered part of North America. (Also, a large chunk of Siberia also belongs to North America, geologically speaking.)

As with planets, continents were defined in antiquity according to non-scientific criteria. Trying to retroactively define continents scientifically is pointless. Continents are defined culturally.

As has been said, the boundary between the smallest continent and largest island is arbitrary. The largest gap in size is between Australia and Greenland, so it’s convenient to place the dividing line there.

Did it ever say anywhere that a continent had to be an entire contiguous landmass?

In just one of the many opinion sites, there were four reasons:

  1. Australia and Antarctica are geologically distinct continental land mass while Greenland is just a minor accretion from North America, the same way the British Isles and Borneo appear to be subordinated to the European landmass and the Asian landmass, respectively.

  2. AA have unique flora and fauna while G doesn’t (iffiest reason.)

  3. AA have unique cultures while G doesn’t (what???)

  4. Local opinion: mixed sentiments for AA but consistent “island” pronouncement for G

1 already looks good to me, though I’m not an Earth scientist.

However, North America is linked to Eurasia by continental shelf in exactly the same way that North America is linked to Greenland. By that argument, Eurasia and the Americas are a single continent. (And as I mentioned above, eastern Siberia is geologically part of North America.)

As I said, any attempt to come up with a scientific definition of continent that conforms to the traditional number of continents (even if one considers Eurasia to be a single continent) is doomed to failure. Any such definition will either have exceptions or inconsistencies, or will be completely artificial. Continents are basically whatever we say they are; there is no scientifically valid definition.

Current thinking by some scientists. It’s not even universally accepted by scientists in the field. :rolleyes:

I still think it’s absurd to consider “The Americas” to be a single continent, especially if you’re also considering Europe and Asia as separate. If you try to cut the outline of the Americas out of a piece of paper, it’s going to fall apart somewhere in the vicinity of Panama. Likewise, if you try to cut out Eurasiafrica, Africa is going to fall off. But no way is Eurasia going to come apart.

Actually, it’s the geologists’ version of clickbait. The authors get more attention by making such an extraordinary claim. Given that there is no standard definition of a “geological continent,” identifying Zealandia as one is ridiculous. I’m surprised a journal like the GSA would have published something like that.

Your problem is that you are expecting the definition of continents to make sense.:wink:

Maybe it’s just a dwarf continent…

You could write a whole book about the subject, and the answer would be different in different languages and at different times. 300 years ago, in English, there were only two “continents”, the Old World and the New World. But the seven-continent system is the one that is current in English today.

By the way, the word continent is related to the word contain.

Indeed, tectonically speaking, Australia is no innocent lone wanderer. It’s taken other, non-consenting countries for a ride—kidnapped them, so to speak.

Let’s face it, Australia is a bad country. Very bad! It keeps me up late at night thinking of those innocent acting Australians smugly eating their meat pies and pavlova (I heard they put Vegemite in it when they serve it to foreigners) and riding their kangaroos, knowing they’ve taken innocent countries hostage. And, if we go over there to get them to confess, they’ll sic their funnel web spiders on us!

That’s a totally different animal. The continent/island distinction is totally arbitrary, consisting of “these seven landmasses are continents, everything else is an island.” Pluto was downgraded to a planetoid because astronomers realized it didn’t actually fit their definition of a planet.

I realize that definition itself is somewhat arbitrary itself, but it’s at least a standard against which you can determine whether a new object would fit. If Atlantis rose from the seafloor, and it was much, much larger than Greenland, but just a bit smaller than Australia, we’d probably calling it a continent and ruining our old definition.

Astronomers realized that Pluto didn’t fit their definition right after they changed the definition in such a way as to exclude Pluto.

To be fair, there really wasn’t a formal or technically rigorous definition of what characteristics make a planet prior to the International Astronomical Union (IAU) definition in August 2006, and any application of rules that would make Pluto a planet would also have to included at least a significant number of other Solar-orbiting bodies and potentially several moons. The current IAU definition is sensible as far as it goes, although for utility in planetary science they really need to be divided into finer categories based upon functional characteristics (size, composition of the atmosphere and lithosphere, absence or presence of water and organic compounds, et cetera).

Although there is no rigorous definition of a continent from a purely geographic standpoint beyond being arbitrarily large land masses, in terms of anthropology continents have distinct population groupings, hence why the modern identification of human “races” roughly corresponds to the continents of origin. The “native” Greenlanders are Inuits who settled there in the 13th and 14th centuries, so from an ethnographic view there is no unique Greenlandic “race”. Of course, race has no rigorous scientific definition either, and of course there are no natives on Antarctica. So, ultimately, Greenland’s designation of being an island rather than a continent is mostly arbitrary.


Old (though not ancient, for obvious reasons) lists of planets prominently include Ceres and its ilk. So striking such objects off the list of “major planets” (and precedent for tweaking the definition) to keep the list short definitely predates anything to do with Pluto.

Which begs the question “Why is Texas it’s own country”?


At least this Latin American (and most Peruvians) were taught unitl 20 years ago or so that there were actually THREE continents in the “American landmass” : North (Canada US Mexico) Central (From Guatemala to Panama) and South America.

It was an educational mini-revolution to go down to TWO continent (North and South) and even then, for political and cultural reason, nobody really thinks that Nicaragua or Costa Rica are really in North America in the same way that when your say “Asian” you don’t think Armenian or Yemeni.

Also, for good measure, we were taught (and many books still teach it) that Oceanía was a continent made of all the Pacific islands plus Australia and New Zealand. Interesting enough, the Caribbean was either forgotten or lumped into Central America.