Definition
Desertification is what happens in dry regions with little rainfall when climate change and careless land use cause green grasslands and farmland to lose their vitality and turn into barren, desert-like land. It means the land's ability to hold nutrients and moisture drops sharply.
Land dries out and cracks like chapped skin
When moisturizer disappears from our skin, it quickly turns rough and cracks open. The land works the same way. Grasses and trees send roots deep into the ground to hold the soil firmly in place, and when rain falls, they soak up the water like a sponge. They act as the land's natural moisturizer.
But if too many livestock graze and eat the grass down to nothing, or if all the trees in a forest are cut for firewood and farming, the plant cover that protected the ground vanishes in an instant. Without its shield, the soil bakes dry in the strong sun, and the precious topsoil (the nutrient-rich upper layer of soil) blows away in the wind.
In the end, all the moisture in the ground evaporates, leaving nothing but barren dust where plants can't live. Once the ground has hardened, it can't take in water even when it rains, and the water simply runs off the surface. With no water held in the soil, plants can't grow, and this vicious cycle repeats again and again.
Natural drought and human greed work together
Desertification doesn't come from drought alone, from the sky simply withholding rain. It mostly happens in "arid and semi-arid regions," where the rainfall is neither very little nor very much. The land isn't generous, but grasses and small trees live there in a delicate balance.
But as the population grew rapidly, people began to treat this fragile land far too harshly. They planted crops without giving the land time to recover, and pumped up groundwater recklessly for farm use. They also raised far more livestock than the land could bear, and the animals tore up even the grass roots.
On top of that came abnormal heat and severe drought from global warming, and the destruction of the land sped up out of control. Desertification is the result of natural climate change and humanity's careless damage to the environment meshing like gears and choking the life out of the land.
To be more precise
Many people think desertification means the sand of a huge desert like the Sahara blowing across the land into the next neighborhood. To be more precise, though, desertification is the process in which grasslands and farmland in dry regions that were perfectly fine lose much of their soil's productivity.
It's not that a desert monster walks toward us. The nutrients and microbes in the ground we stand on disappear, and the land dies like a desert right where it is. Once rain and wind wash the topsoil away, it takes hundreds to thousands of years to return to fertile soil where plants can grow again.
As a result, people can't farm and suffer severe food shortages, and some leave their homes and become environmental refugees. The yellow dust that clouds Korea's skies in spring comes mainly from the deserts and dry zones of Mongolia and China, and desertification of the grasslands around them is counted as one of the causes that make the dust worse.
Common misconceptions
Desertification is when the sand dunes of an existing desert are blown over and bury the land around them.
The sand isn't coming in from outside. The plants on grasslands and farmland that were perfectly fine are destroyed, and the soil right there dries out and turns desert-like on its own.
Where you meet it
In the Sahel, south of Africa's Sahara, a major drought in the 1970s and 80s combined with overgrazing and overfarming to ruin wide grasslands, and even now, recovery and degradation of the land are mixed together in different places.
The drying of the dry grasslands of Mongolia and northern China is counted as one of the causes that make the yellow dust blowing into Korea in spring worse.
In one sentence
Desertification is when climate change and careless land use make grasslands and farmland lose their moisture and vitality and dry out like a desert.