Land
Land makes up just 29.2% of Earth's surface. The rest is ocean. That solid, dry terrestrial surface, the part not submerged beneath an ocean or another body of water, holds every continent and every island. It is where Earth's first cellular life likely began, even though modern terrestrial plants and animals evolved from aquatic creatures. One-third of it is covered in trees. Another third is given to agriculture. One-tenth lies under permanent snow and glaciers. The remainder is desert, savannah, and prairie. A single gram of its soil can contain billions of organisms belonging to thousands of species, most of them microbial and still largely unexplored. How did this surface form, and why does it heat and cool faster than the air or the water around it? What forces carve it, and what happens when humans push it past its limits? Survival here leans on something scarce. Fresh water from rivers, streams, lakes, and glaciers makes up only three percent of all the water on Earth.
4.5672 billion years ago is the date of the earliest material found in the Solar System. Earth itself must have formed by accretion around that time, growing out of a circumstellar disc of gas, ice grains, and dust spun out of a collapsing molecular cloud. The primordial Earth's assembly took ten to twenty million years. By 4.54 billion years ago, that primordial Earth had formed.
Volcanic activity and outgassing, including water vapour, gave Earth its first atmosphere and oceans. Condensation supplied much of the water, augmented by ice delivered by asteroids, protoplanets, and comets. Greenhouse gases kept those new oceans from freezing while the young Sun shone at only 70% of its present luminosity. By 3.5 billion years ago, Earth's magnetic field was established, shielding the atmosphere from being stripped away by the solar wind.
Continents are built by plate tectonics, a process driven by the continuous loss of heat from Earth's interior. Across hundreds of millions of years, supercontinents have assembled and torn apart three times. Roughly 750 million years ago, one of the earliest known supercontinents, Rodinia, began to break apart. The continents recombined into Pannotia between 600 and 540 million years ago, then into Pangaea, which itself broke apart 180 million years ago. Today there are four major continuous landmasses: Africa-Eurasia, America, Antarctica, and Australia.
The elevation of Earth's land runs from 418 metres below sea level at the Dead Sea to 8,848 metres at the summit of Mount Everest. The mean height of land above sea level is about 797 metres, and 98.9% of dry land sits above sea level at all. Terrain, an area of land and its features, shapes travel, mapmaking, ecosystems, and the flow of surface water. Flatter alluvial plains tend to carry better farming soils than steep, rocky uplands.
Relief describes the difference in elevation within a landscape. Flat ground has low relief; a landscape with a large gap between its highest and lowest points has high relief, and most land has relatively low relief. A topographic map renders this in contour lines that connect points of equal elevation, with hypsometric tints, colours placed between the lines, marking height relative to sea level.
Upland and lowland are more than directions on a map. In river ecology, upland rivers run fast and cold, drawing different fish than the slow, nutrient-rich lowland rivers where macrophytes flourish. Moorland refers to upland shrubland with acidic soils, while heathland is its lowland counterpart. The boundary between land and sea, meanwhile, has its own name: the shoreline.
Over the past 70 million years, the Colorado River cut the Grand Canyon, and scientists estimate it still erodes the canyon at a rate of 0.3 metres every 200 years. Geomorphology studies these natural processes that shape the surface into landforms. Erosion moves one part of land to another by wind, water, ice, and gravity. Weathering, by contrast, wears rock down in place without carrying it anywhere. Humans have sped erosion to between 10 and 40 times its normal rate, stripping away half the topsoil of Earth's land surface within the past 150 years.
In 1912, the scientist Alfred Wegener first hypothesized continental drift, the idea that continents move relative to one another. Researchers built on it through the 20th century into the now widely accepted theory of plate tectonics. Earth's lithosphere is divided into tectonic plates that move over the mantle. Where two plates meet is a plate boundary, and different boundaries produce different phenomena. Divergent boundaries usually show seafloor spreading. Convergent and transform boundaries host subduction zones.
The Ring of Fire surrounds the Pacific Ocean and holds two-thirds of the world's volcanos. It also accounts for over 70% of Earth's seismological activity. Where a plate is pushed above another at a convergent boundary, mountains rise through orogenesis, by collision that thrusts crust upward or by subduction that melts crust and lifts it back as hardened rock.
Earth's land surface heats up and cools down faster than air or water, which is why it weighs so heavily on climate. Latitude governs how much solar radiation reaches the ground, with high latitudes receiving less than low latitudes. Topography reshapes airflow and precipitation: large mountain ranges divert wind and force air parcels to rise, cool, and release condensation and rain.
Albedo measures how much solar radiation a surface reflects rather than absorbs. Vegetation has a relatively low albedo, making vegetated surfaces good absorbers of the Sun's energy. Forests reflect 10 to 15 percent, grasslands 15 to 20 percent, and sandy deserts a far brighter 25 to 40 percent.
Densely populated cities run warmer than their surroundings and create urban heat islands. These islands alter the precipitation, cloud cover, and temperature of the region around them. About 30 percent of land carries a dry climate, losing more water to evaporation than it gains from precipitation.
44% of all people live within 150 kilometres of the sea, according to a United Nations atlas. The shoreline itself migrates each day as tides rise and fall, and over longer spans as sea levels shift. Coastal mangroves provide the primary source of fuel wood and building materials in many countries. Coastal ecosystems also sequester carbon at a much higher rate than many terrestrial ones, taking up atmospheric carbon dioxide. Along tropical coasts with clear, nutrient-poor water, coral reefs grow between depths of 1 and 50 metres.
A subcontinental area of land surrounded by water is an island, and a chain of them is an archipelago. The Hawaiian islands formed from isolated volcanic activity, even though they sit far from any plate boundary. Atolls are ring-shaped coral islands, left behind when subsidence sinks an island and leaves a ring of reefs around the gap.
Soil is a three-state system of solids, liquids, and gases, born from climate, relief, organisms, and parent minerals interacting over time. Ecologists treat it as an ecosystem in its own right, holding a prominent share of Earth's genetic diversity. It is also a major carbon reservoir, and one of the most reactive to human disturbance. As the planet warms, soils have been predicted to release carbon dioxide through increased biological activity, a positive feedback, though that prediction has been questioned on more recent knowledge of soil carbon turnover.
892 million agricultural workers depended on land for their livelihoods worldwide in 2025. For more than 10,000 years, humans have hunted, foraged, burned, cleared, and farmed on land. The Neolithic Revolution spread agriculture until Earth's landscape was essentially transformed worldwide by 3000 years ago. From around 1750, the Industrial Revolution drove land use upward at an accelerating rate, demanding more resources and feeding rapid population growth.
In 2007, the global population crossed from a majority living in rural areas to a majority living in cities, even though urban areas cover less than 3 percent of Earth's land. City dwellers depend on food grown in rural areas, pushing land use change far beyond city limits. Urban expansion also tends to take the most fertile land, forcing agriculture onto poorer ground where more area is needed for the same output.
The phrase the law of the land first appeared in 1215 in Magna Carta, and later shaped the United States Constitution. Common land, collective ownership treated as a common good, also began in medieval English law. The tragedy of the commons describes how individuals deplete shared spaces by taking more than their fair share. From the late 20th century, the international community began recognising Indigenous land rights in law, including the Treaty of Waitangi for Maori people, the Act on Greenland Self-Government for Inuit, and the Indigenous Peoples Rights Act in the Philippines.
The Mongol Empire of the 13th and 14th centuries grew into the largest contiguous land empire in history through war and conquest. Many conflicts have been fought to expand the land under a group's control or to seize areas held to carry strategic, historical, or cultural weight. In the 19th-century United States, the concept of manifest destiny held that American settlers were destined to spread across North America, and it was used to justify military action against the indigenous peoples of North America and of Mexico.
Lebensraum, meaning living space, drove part of the aggression of Nazi Germany in World War II. It had first become a geopolitical goal of Imperial Germany in World War I, as the core element of the Septemberprogramm of territorial expansion. The Nazi Party carried it to its most extreme form, and it remained policy until the war's end.
Humans have altered more than three-quarters of ice-free land, fundamentally changing ecosystems and helping drive the Holocene extinction, Earth's sixth mass extinction, which so far has proven irreversible. Salinization alone harms at least 20% of all irrigated lands. The coal that powers much of this expansion is not renewable, taking millions of years to form, and its current supply is expected to peak in the middle of the 21st century.
Common questions
What is land and how much of Earth's surface does it cover?
Land is the solid terrestrial surface of Earth not submerged by the ocean or another body of water, including all continents and islands. It makes up 29.2% of Earth's surface. Most of it is covered by regolith, a layer of rock, soil, and minerals forming the outer part of the crust.
How is land on Earth divided between trees, farming, and ice?
One-third of land is covered in trees, another third is used for agriculture, and one-tenth is covered in permanent snow and glaciers. The remainder consists of desert, savannah, and prairie. About 30 percent of land has a dry climate.
What are the highest and lowest points of Earth's land surface?
Earth's land elevation ranges from 418 metres below sea level at the Dead Sea to 8,848 metres at the summit of Mount Everest. The mean height of land above sea level is about 797 metres, and 98.9% of dry land sits above sea level.
Who first proposed the theory of continental drift?
The scientist Alfred Wegener first hypothesized the theory of continental drift in 1912. Researchers developed his idea throughout the 20th century into the now widely accepted theory of plate tectonics, in which Earth's lithosphere is divided into tectonic plates that move over the mantle.
How has human activity affected land degradation and erosion?
Humans have caused erosion to run 10 to 40 times faster than normal, stripping away half the topsoil of Earth's land surface within the past 150 years. Humans have altered more than three-quarters of ice-free land, and salinization affects at least 20% of all irrigated lands.
Where did the phrase the law of the land come from?
The phrase the law of the land first appeared in 1215 in Magna Carta, which inspired its later usage in the United States Constitution. The related idea of common land also originated with medieval English law, referring to collective ownership treated as a common good.