Earth’s Desert Disease

Hot, dry, and barren—this is the image that often comes to mind when imagining the desert. Most of us have never actually seen a desert in person; our experiences are limited to movies or documentaries. Soon, this may no longer be the case. Deserts—lands with extremely low precipitation—have recently been growing in land mass at dangerous rates, with the world’s largest desert, the Sahara in North Africa, expanding by 10 percent in the past century. This is the result of a process known as desertification, in which massive swaths of land become more desert-like. This process is characterized by the loss of vegetation and drying soils. With Earth’s current rate of desertification, the land area of deserts will continue to increase in future generations if nothing is done to limit its effects.

Deserts are one of Earth’s biomes, which are areas grouped based on their climates and vegetation that have distinct wildlife and soil types. The classification of a desert is straightforward: it is any area of land that receives less than 50 centimeters (20 inches) of rain per year. Its simplicity makes it a broad classification. For example, areas such as Antarctica are technically considered deserts since other factors—such as vegetation and temperature—are not considered, and Antarctica only receives around 6.5 inches of rain per year. This also makes deserts the only terrestrial biome found on every continent. 

Of the major terrestrial biomes, deserts are the second most prevalent, taking up approximately 20 percent of Earth’s land, while forest biomes represent 33 percent. However, these percentages are currently fluctuating due to the negative environmental impacts of human activities. Desertification is primarily caused by climate change—more specifically deforestation, overgrazing, and unsustainable mining and farming practices. All of these causes have a common denominator: humans. Human activities are the main driving force behind all of our environmental crises, and desertification is no exception. 

As the global temperature rises due to climate change, weather extremes, such as droughts, become more common. Decreasing precipitation levels prevent plants and animals from surviving in environments that previously had higher rainfall, resulting in a loss of biodiversity. 

Unsustainable mining, deforestation, and farming all disrupt land and affect soil. Take the case of topsoil, which is a soil layer containing the nutrients needed for vegetation growth. Mining and deforestation displace topsoil and emphasize the effects of erosion, or the transportation of materials, as tightly packed soil is loosened. Farming practices such as over-irrigation lead to water erosion, in which water carries too much topsoil away and makes land unusable. As more land becomes unusable due to the loss of soil nutrients, deserts are formed. 

One of the human causes, overgrazing, can be reversed to prevent desertification. In the meat industry, many ranchers release their cows into the wild without monitoring their feeding. This form of open-ranch grazing leads to overgrazing, in which cows consume too much of the grass in an area. The destruction of the grasses’ roots—which hold the soil in place—and the cows’ trampling amplify erosion and contribute to desertification. Instead of overgrazing, controlled grazing should be utilized to slow and even prevent desertification. Mimicking the movement and grazing of wild herds that have died out as a result of climate change and desertification could support soil health and vegetation. This process, known as holistic grazing, is done by introducing animals, such as cattle and sheep, and allowing them to wander freely in sectioned-off areas. This practice leaves behind layers of dung, providing nutrients to the soil without leading to overgrazing. Such processes can help return environments to their normal nutrient cycles and counteract the effects of desertification.

Desertification is particularly dangerous because deserts are vulnerable to drastic change. Deserts have extremely low biodiversity because their harsh climates allow only a small selection of plants and animals to survive. As a result, any changes that affect the survival of these adapted plants and animals can cause the complete collapse of the desert ecosystem. For example, bird communities have collapsed in the Mojave Desert as a result of increasing temperatures caused by climate change. 

As more biomes turn into deserts, biodiversity is lost and ecosystems are disrupted. For example, the Sahara desert used to be a lush grassland that received far more rainfall than it does currently. The Earth’s current rate of desertification impacts around a third of all the land on Earth, with four million square kilometers being affected by this process and an additional 120,000 square kilometers being classified as desert per year. 

Desertification is not an issue of the future, and addressing it must not be postponed any further. As deserts slowly infiltrate the biomes of the Earth, this process may soon become irreversible and will only be further perpetuated if necessary action is not taken. However, all hope is not lost for bringing back our green Earth. For example, the Agriculture Improvement Act of 2018 provides support for farmers in the U.S. and promotes voluntary conservation, aiming to decrease over-irrigation and excess topsoil erosion on farms. New practices such as holistic farming are being researched and implemented to reverse and slow desertification, providing hope for a future that is—quite literally—greener.