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Land

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Land is the solid, terrestrial surface of Earth that is not submerged by oceans or other bodies of water. It accounts for 29.2% of the planet's total surface area and includes all continents and islands.

The Earth seen from Apollo 17 with transparent background
The Earth seen from Apollo 17 with transparent background

Most of this surface is covered by regolith. Regolith is a layer consisting of rock, soil, and minerals that forms the outer part of the crust. Land is not just a physical surface; it also represents the collective natural resources of the planet. This includes rivers, lakes, groundwater reserves, and the biosphere, which is the zone where life exists.

7 - Itahuania - Août 2008
7 - Itahuania - Août 2008

The formation of Earth and its land began approximately 4.54 billion years ago.

Earth formation
Earth formation

The process likely started with the gravitational collapse of a solar nebula. This nebula contained gas, ice grains, and dust. As particulate matter accumulated through cohesive clumping and gravity, planetesimals began to form. The primordial Earth assembled over a period of 10 to 20 million years. Eventually, the molten outer layer of the planet cooled. This cooling allowed the solid continental crust to form. Volcanic activity and outgassing also helped create the atmosphere and oceans.

Continental models
Continental models

Plate tectonics is the primary mechanism that shapes the Earth's large-scale landforms. This theory explains that the lithosphere is divided into several tectonic plates. These plates move over the mantle due to the continuous loss of heat from the Earth's interior. This movement causes continental drift, where continents move relative to one another.

Continental models
Continental models

When plates meet at boundaries, they create different geological phenomena. For example, the Ring of Fire contains two-thirds of the world's volcanoes. This area is also home to over 70% of the world's seismological activity. These processes have caused supercontinents to form and break apart three times over hundreds of millions of years. One early supercontinent was Rodinia, which began to break apart roughly 750 million years ago. Later, Pannotia formed, followed by the well-known supercontinent Pangaea, which broke apart 180 million years ago.

Landforms are categorized by their terrain and elevation. Terrain refers to the specific features of an area, such as mountains, deserts, plains, or plateaus. Elevation is the vertical distance between a point and sea level. The land surface varies significantly in height. The highest point is Mount Everest, which reaches an altitude of 8,848 metres.

Mt Fuji NASA ISS002-E-6971 large
Mt Fuji NASA ISS002-E-6971 large

Conversely, the lowest point is the Dead Sea, situated at -418 metres. Most dry land, about 98.9%, sits above sea level. Geologists also study relief, which is the difference in elevation within a landscape. High relief describes areas with large elevation changes, while low relief describes flatter areas.

AlluvialPlain
AlluvialPlain

Natural processes constantly reshape the landscape through weathering and erosion. Weathering wears away rock and solid land without moving the material. Erosion, however, involves the transport of land from one location to another. This occurs via wind, water, ice, and gravity. Streams are a major part of the water cycle and help shape the land. They carve rocks, transport sediments, and replenish groundwater.

AlluvialPlain
AlluvialPlain

Glaciers also play a role, especially at high elevations or latitudes. Over hundreds or thousands of years, snow compacts and recrystallizes into ice. These glaciers can become so heavy that they actually warp the Earth's crust.

Land cover is distributed into several distinct types based on climate and biology. About one-third of the world's land is covered by trees. Another third is utilized for agriculture to support human needs. Approximately one-tenth of the land is covered by permanent snow and glaciers. The remaining areas consist of deserts, savannahs, and prairies. About 30% of the land has a dry climate. This occurs because the area loses more water through evaporation than it receives from precipitation. This imbalance, along with Earth's rotation and uneven sun distribution, helps generate winds.

Human activity has a profound impact on the Earth's land and its stability. Humans manipulate the land through architecture and large-scale agriculture. However, these activities can also lead to rapid environmental changes. For example, human actions have caused erosion to occur 10 to 40 times faster than normal. In the last 150 years, half of the Earth's surface topsoil has been lost.

World soil degradation
World soil degradation

Because land is essential for survival, scientists now focus on sustainable management. This includes restoring degraded soil, protecting endangered species, and preserving biodiversity. Managing the land and the biosphere is critical to addressing global climate change.

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🖼️ Images & Media (31)
File:Forest area as a percentage of land area, by region, 2025.svg
Forest area as a percentage of land area,...
File:Temperature Change Measured Over Land By Region.svg
Temperature Change Measured Over Land By...
File:Definition of Free Cultural Works logo notext.svg
Definition of Free Cultural Works logo notext.svg
File:Coastline as seen from Chimney Rock, Point Reyes National Seashore.jpg
Coastline as seen from Chimney Rock,...
File:Satellite image of Bolivia in June 2002.jpg
Satellite image of Bolivia in June 2002.jpg
File:Ryssebergen 2012b.jpg
Ryssebergen 2012b.jpg
File:Anthromes map and timeline (10,000 BCE to 2017 CE).png
Anthromes map and timeline (10,000 BCE to...
File:Kashmir region. LOC 2003626427 - showing Kashmir division administered by India in neon blue.jpg
Kashmir region. LOC 2003626427 - showing...
File:2013-morbihan-ile-berder-rankosol-granite0109.jpg
2013-morbihan-ile-berder-rankosol-granite0109.jpg
File:Spiaggia rosa, isola di budelli, sardegna.jpg
Spiaggia rosa, isola di budelli, sardegna.jpg
File:AlluvialPlain.JPG
AlluvialPlain.JPG
File:Land cover IGBP.png
Land cover IGBP.png

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