CountryData and the areas of the world

Question

If I add the water area and the land area of the world, I get the same number as if I asked for the total area of the world in the first place:

In[1]:= {CountryData["World", "WaterArea"] + CountryData["World", "LandArea"],
         CountryData["World", "Area"]}

Out[1]= {5.10066*10^8, 5.10066*10^8}

Now, if I add the area of all the countries, it does not add up to the total land area of the world:

In[2]:= {Total[CountryData[#, "Area"] & /@ CountryData[]], 
         CountryData["World", "LandArea"]}

Out[2]= {1.35936*10^8, 1.4912*10^8}

So my question is: are some countries missing? Are the ice caps to blame?

Answer 1

So both

CountryData["World", "LandArea"] - 
(CountryData["Antarctica", "LandArea"] +
 Total[CountryData[#, "LandArea"] & /@ CountryData[]])

and

CountryData["World", "LandArea"] - 
  Total[Flatten[CountryData[#, "LandArea"] & /@ CountryData["Continents"]]]

give $3.42636\times10^6 \text{ km}^2$ of area missing. That is approximately the area of current Arctic ice (I Googled it).

Also, there are some places that occupy a land area, but are not within any country (about maybe $10^4 \text{ km}^2$ in total); e.g., the Saudi–Iraqi neutral zone.