Global characteristics

Total surface of the earth: 510 million square kilometres.

Area covered by land: 149 million square kilometres (29%).

Area covered by water: 361 million square kilometres (71%).

 93% of the water coverage is made up of 5 oceans:

The other 7% of the water coverage (about 26 million square kilometres) is made up of adjacent seas:

Of these, the largest section is taken up by three Mediterranean seas (European Mediterranean; Caribbean Mediterranean (incl. Gulf of Mexico); and the East Indian Archipelago]: about 15 million square kilometres.

The small mediterranean seas represent 2.3 million square kilometres (Red Sea, Persian Gulf, Baltic, Hudson Bay).

The marginal seas make up about 8 million square kilometres [e.g. North Sea, English Channel, Irish Sea, Japan Sea, Gulf of California, etc].

Ocean boundaries

The official maritime boundaries are decided by the International Hydrographic Organisation:

The maritime boundaries of the 5 Oceans are

(see http://en.wikipedia.org/wiki/File:World_ocean_map.gif):

Global means and extremes

Topography of the bottom


From: Gross, Oceanography: a view of the earth, 1977