by Sara Slavikova
As other natural ecosystems, deserts have their own dynamics independent of human activities. Throughout history, sand dunes have been retreating or slowly expanding into adjacent areas when given the chance. But processes that happen during desertification are different. They do not follow natural patterns, more unpredictable and dangerous, and can happen much quicker.
Lands that were once covered with a carpet of perennial grasses, woody shrubs, and dense forests have reportedly turned to barren grounds where only wind sweeps dust around and rain water flushes down muddy sediments whenever it rains. These are lands that were green a decade ago or so. Local residents still remember when their livestock had grass to graze, their fathers grew crops and their mothers warned them of not playing in the forests because they could get lost.
It doesn’t matter who shares these memories or from which country that person originates, their stories are the same. Their homes are being swallowed up by dust and sand as desertification creeps closer. Pastures and crops have disappeared, and water sources became scarce. The situation feels hopeless and most of these people do not know what their future looks like.
Will they still be there living among the dust with diminishing resources? Will they leave? Or can desertification be stopped?
HOW DOES DESERTIFICATION HAPPEN?
Desertification is not natural expansion of deserts. In fact, natural deserts do not even have to be close to areas where desertification happens. Desertification is a form of land degradation caused by poor land management of dry-lands rather than spreading of existing deserts.
This means that the degradation is mainly caused by our land use activity, when we alter natural ecosystems and, consequently, rain cycles in arid and semi-arid areas. Lands vulnerable to desertification transform into deserts because their soil becomes progressively drier, poor, and unable to support plant growth. Once desertification occurs, the most productive soil layer, known as topsoil, gets blown away by wind or washed off by rain rather quickly because there is no vegetation to protect it. With topsoil gone, important soil nutrients with organic material are lost.
Soil then loses its structure and the ability to nourish plants and soil fauna. It dries out and hardens making it increasingly difficult for any following rainfall to penetrate below the surface. When rain cannot infiltrate into deeper soil layers, it runs off instead of keeping soils moist and replenishing groundwater reservoirs. As you can imagine, this continually makes the area drier. The conditions are gradually getting worse and even the most drought resistant plants eventually die, leaving the barren land exposed to complete degradation.
WHAT IS THE DIFFERENCE BETWEEN DROUGHT AND DESERTIFICATION?
The definition of drought is a period of unusually low precipitation that is long enough to cause water scarcity and deplete soil moisture to the point where vegetation (including crops) dwindles. Dry-lands, areas that are the most susceptible to desertification, are characterized by periods of droughts that lead to water scarcity and drying vegetation, but then when rains come, they re-green again and vegetation, animals and people prosper. These cycles are characteristic to dry-lands and life has adapted around them. They also change according to changing climate and other complex factors influencing local water cycle, with some periods lasting longer than usual, even years, some lasting shorter. But they have always been there. Periods of abundance and periods of decline.
Area stricken by desertification might look the same at the first look as an area affected by drought, but there is one big difference, and that is what happens when the rain comes.
Despite of looking horribly dry and damaged, natural dry-lands will turn green and lush again; soils will mend; water creeks will start flowing and wells will refill with water. While lands degraded to the point of desertification, they’ll remain lifeless. The only effect rainwater will have on them will be erosion and flooding.
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