How Much of the Earth Is Covered by Desert?

Approximately one-third of the Earth’s land surface is classified as desert, a staggering testament to the power of aridity and the diverse forms it takes. These landscapes, often perceived as barren wastelands, are actually complex ecosystems harboring specialized life forms and playing crucial roles in global climate patterns.

Understanding Desert Landscapes

Deserts are more than just sand dunes. They are defined by their arid climate, specifically receiving very little precipitation. This lack of moisture shapes the terrain, vegetation, and animal life found within them.

Factors Contributing to Desert Formation

Several factors converge to create desert environments:

Atmospheric Circulation: Global air circulation patterns, like the Hadley cells, create zones of descending air that suppress rainfall, leading to many of the world’s largest deserts found around 30 degrees latitude north and south of the equator.
Rain Shadow Effect: Mountain ranges block moisture-laden air, causing precipitation on the windward side and leaving the leeward side dry, creating “rain shadow” deserts.
Distance from Oceans: Inland regions far from oceanic moisture sources often experience arid conditions.
Cold Ocean Currents: Cold ocean currents can stabilize the atmosphere, reducing rainfall over adjacent land areas.

Types of Deserts

Deserts are not homogenous; they exhibit a wide range of characteristics, leading to different classifications:

Hot Deserts: These are the stereotypical deserts, characterized by high temperatures and extreme dryness. The Sahara and the Arabian Desert are prime examples.
Cold Deserts: Located in high latitudes or altitudes, these deserts experience cold winters and relatively dry summers. The Gobi Desert is a notable example.
Coastal Deserts: Bordering coastlines, these deserts are influenced by cold ocean currents and may experience fog and high humidity despite low precipitation. The Atacama Desert is the driest non-polar desert on Earth.
Polar Deserts: Although covered in ice and snow, polar regions can be considered deserts due to their extremely low precipitation levels. Antarctica is the largest desert on Earth by this definition.

The Impact of Deserts

Deserts are far from insignificant landscapes. They exert a considerable influence on the planet:

Climate Regulation: Deserts influence global air and water currents and can reflect significant amounts of solar radiation back into space.
Biodiversity Hotspots: Despite the harsh conditions, deserts support unique and highly adapted plant and animal species.
Mineral Resources: Deserts are often rich in mineral deposits, including oil, natural gas, and various ores.
Cultural Significance: Deserts have been home to various cultures for millennia, shaping their traditions and livelihoods.

Addressing Misconceptions About Deserts

Many misconceptions surround deserts. They are not simply barren wastelands. Many deserts support a surprising amount of life, and they contribute significantly to the overall health and functioning of the planet. Understanding these ecosystems is crucial for responsible management and conservation efforts.

FAQs About Deserts

FAQ 1: What exactly defines a region as a desert?

A region is typically classified as a desert if it receives an average of less than 250 millimeters (10 inches) of precipitation per year. However, temperature, evaporation rates, and soil type also play a role in determining aridity.

FAQ 2: Are all deserts sandy?

No, this is a common misconception. While some deserts, like parts of the Sahara, are dominated by sand dunes (called ergs), many others are characterized by rocky terrain, gravel plains (called reg or gibber), or exposed bedrock.

FAQ 3: What is the largest hot desert in the world?

The Sahara Desert, located in North Africa, is the largest hot desert in the world, covering an area of approximately 9.2 million square kilometers (3.6 million square miles).

FAQ 4: What is the driest place on Earth?

The Atacama Desert in Chile is considered the driest non-polar place on Earth. Some areas within the Atacama have reportedly never received rainfall.

FAQ 5: Can plants and animals survive in deserts?

Yes, many plants and animals have adapted to survive in the harsh conditions of deserts. Xerophytes are plants adapted to drought conditions, using strategies like deep root systems, water storage, and reduced leaf surface area. Animals may be nocturnal, burrow underground, or have physiological adaptations to conserve water.

FAQ 6: What is desertification?

Desertification is the process by which fertile land becomes desert, typically as a result of drought, deforestation, or inappropriate agricultural practices. It is a serious environmental problem that threatens food security and livelihoods in many regions.

FAQ 7: What are some of the main causes of desertification?

The main causes of desertification include: overgrazing, deforestation, climate change, unsustainable agriculture, and improper irrigation. These factors contribute to soil erosion, loss of vegetation cover, and reduced water availability.

FAQ 8: How can desertification be prevented or reversed?

Preventing and reversing desertification requires a combination of strategies: sustainable land management practices, such as rotational grazing, afforestation (planting trees), soil conservation techniques (e.g., terracing), and improved water management.

FAQ 9: Are deserts expanding?

Yes, in many regions, deserts are expanding due to desertification. Climate change is exacerbating this trend, leading to increased droughts and higher temperatures.

FAQ 10: What is the role of deserts in the global climate?

Deserts play a role in regulating the Earth’s climate. They influence air currents, reflect solar radiation, and can be sources of dust that affects cloud formation and precipitation patterns.

FAQ 11: Are deserts good for anything?

Yes! Aside from harboring unique ecosystems and containing valuable mineral resources, deserts also provide recreational opportunities, such as hiking, camping, and stargazing. They are also sources of inspiration and wonder for many people. Furthermore, they have potential for solar energy generation.

FAQ 12: Can deserts be farmed?

In some cases, yes, with appropriate technologies and sustainable practices. Irrigation is often necessary, but it must be carefully managed to avoid salinization (the buildup of salt in the soil). Techniques like hydroponics and vertical farming are also being explored to grow crops in desert environments.