<P> The crust, which currently forms the Earth's land, was created when the molten outer layer of the planet Earth cooled to form a solid mass as the accumulated water vapor began to act in the atmosphere . Once land became capable of supporting life, biodiversity evolved over hundreds of million years, expanding continually except when punctuated by mass extinctions . </P> <P> The two models that explain land mass propose either a steady growth to the present - day forms or, more likely, a rapid growth early in Earth history followed by a long - term steady continental area . Continents formed by plate tectonics, a process ultimately driven by the continuous loss of heat from the Earth's interior . On time scales lasting hundreds of millions of years, the supercontinents have formed and broken apart three times . Roughly 7016236682000000000 ♠ 750 mya (million years ago), one of the earliest known supercontinents, Rodinia, began to break apart . The continents later recombined to form Pannotia, 600--7016170411040000000 ♠ 540 mya, then finally Pangaea, which also broke apart 7015568036800000000 ♠ 180 mya . </P> <P> "Land mass" refers to the total surface area of the land of a geographical region or country (which may include discontinuous pieces of land such as islands). It is written as two words to distinguish it from the usage "landmass", the contiguous area of land surrounded by ocean . Earth's total land mass is approximately 148,939,063.133 km (57,505,693.767 sq mi) which is about 29.2% of its total surface . Water covers approximately 70.8% of Earth's surface, mainly in the form of oceans and ice formations . </P> <Table> Land Cover (million ha = 10 000 km) <Tr> <Th> FAO code </Th> <Th> type </Th> <Th> </Th> <Th> </Th> <Th> 2015 </Th> <Th> share </Th> <Th> change fm 92 </Th> <Th> note </Th> </Tr> <Tr> <Td> (6970) </Td> <Td> Artificial surfaces (including urban and associated areas) </Td> <Td> 26.04 </Td> <Td> 34.33 </Td> <Td> 55.40 </Td> <Td> 0.37% </Td> <Td> 29.35 </Td> <Td> </Td> </Tr> <Tr> <Td> (6971) </Td> <Td> Herbaceous crops </Td> <Td> 1,716.22 </Td> <Td> 1,749.58 </Td> <Td> 1,712.15 </Td> <Td> 11.50% </Td> <Td> - 4.06 </Td> <Td> Arable land </Td> </Tr> <Tr> <Td> (6972) </Td> <Td> Woody crops </Td> <Td> 162.86 </Td> <Td> 181.32 </Td> <Td> 199.90 </Td> <Td> 1.34% </Td> <Td> 37.04 </Td> <Td> Arable land </Td> </Tr> <Tr> <Td> (6973) </Td> <Td> Multiple or layered crops </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> Arable land </Td> </Tr> <Tr> <Td> (6974) </Td> <Td> Tree - covered areas </Td> <Td> 4,434.92 </Td> <Td> 4,393.70 </Td> <Td> 4,335.00 </Td> <Td> 29.11% </Td> <Td> - 99.93 </Td> <Td> large decrease </Td> </Tr> <Tr> <Td> (6975) </Td> <Td> Mangroves </Td> <Td> 18.06 </Td> <Td> 18.39 </Td> <Td> 18.74 </Td> <Td> 0.13% </Td> <Td> 0.67 </Td> <Td> </Td> </Tr> <Tr> <Td> (6976) </Td> <Td> Shrub - covered areas </Td> <Td> 1,685.00 </Td> <Td> 1,669.65 </Td> <Td> 1,627.34 </Td> <Td> 10.93% </Td> <Td> - 57.66 </Td> <Td> large decrease </Td> </Tr> <Tr> <Td> (6977) </Td> <Td> Shrubs and / or herbaceous vegetation, aquatic or regularly flooded </Td> <Td> 202.61 </Td> <Td> 194.77 </Td> <Td> 185.39 </Td> <Td> 1.24% </Td> <Td> - 17.23 </Td> <Td> </Td> </Tr> <Tr> <Td> (6978) </Td> <Td> Sparsely natural vegetated areas </Td> <Td> 891.78 </Td> <Td> 878.69 </Td> <Td> 868.07 </Td> <Td> 5.83% </Td> <Td> - 23.71 </Td> <Td> </Td> </Tr> <Tr> <Td> (6979) </Td> <Td> Terrestrial barren land </Td> <Td> 2,001.25 </Td> <Td> 2,000.87 </Td> <Td> 1,884.00 </Td> <Td> 12.65% </Td> <Td> - 117.25 </Td> <Td> large decrease </Td> </Tr> <Tr> <Td> (6980) </Td> <Td> Permanent snow and glaciers </Td> <Td> 78.59 </Td> <Td> 84.32 </Td> <Td> 84.29 </Td> <Td> 0.57% </Td> <Td> 5.70 </Td> <Td> </Td> </Tr> <Tr> <Td> (6981) </Td> <Td> Inland water bodies </Td> <Td> 432.60 </Td> <Td> 435.00 </Td> <Td> 444.57 </Td> <Td> 2.98% </Td> <Td> 11.97 </Td> <Td> </Td> </Tr> <Tr> <Td> (6982) </Td> <Td> Coastal water bodies and intertidal areas </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> (6983) </Td> <Td> Grassland </Td> <Td> 1,793.65 </Td> <Td> 1,806.50 </Td> <Td> 1,801.14 </Td> <Td> 12.09% </Td> <Td> 7.50 </Td> <Td> </Td> </Tr> <Tr> <Th> </Th> <Th> Total Land Mass </Th> <Th> </Th> <Th> </Th> <Th> 14,893.91 </Th> <Th> 100% </Th> <Th> </Th> <Th> </Th> </Tr> </Table>

How much area of the earth is covered with land