Desertification is a process, where a fertile land becomes a desert. You would think that making a dessert from a land flourishing with life would be nearly impossible or would at least, take a long time. Unfortunately, this is not the case. In the last 40 years, we have already lost about a third of the fertile land and we keep losing it. We could say that the biggest problem of converting fertile land to a desert are changes in the water cycle. This, of course, has a lot to do with climate change itself, but there are also other influencing factors.
The water cycle
There are four basic steps in a water cycle: evaporation, condensation, precipitation, and collection. The energy from the sun is responsible for evaporation. The water mostly evaporates from water bodies, soil, and plants (this process is called transpiration). When we change the plant density (deforestation) or alter the environment (drying of wetlands), we influence the amount of water present in an area. With the changed amount of water, the evaporation rate as well as the water cycle, change. The evaporated water turns into water vapor (nothing, we can influence or do about) and after this step, the condensation follows. For this step, water vapor needs a solid core. Water molecules are really not picky and would use dust particles as well as spores or viruses to get the condensation process going. With this, water droplets grow and when they become big enough, they fall back down to Earth (precipitation). All water (doesn’t matter in which form it comes to Earth) is then absorbed by the soil, used by plants or is collected in lakes, streams, and oceans. Because we can, we also influence this step. We build dams to keep water where we want it, as well as change courses of the rivers to make them deliver water elsewhere. In the end, water will continue to evaporate and the natural water cycle will go on. The real problem occurs when the evaporated water is not returned to the area where it was taken from. Because of this, water cycle in some areas changes, which locally (or even globally) changes the climate.
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Alternating the land
Let’s go back to deforestation and drying wetlands for a minute. There are many ways and many reasons why we do it, but first, I would like to point out how we try to produce renewable energy with help of land wind farms. Don’t get me wrong, I think obtaining wind energy is really important and we should definitely make more research in this field! On the other hand, I can’t help myself but I find it very disturbing that they take so much space! So much space, that can’t be used for anything else except for some wind or water erosion.
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Most alterations of land are done for the purpose of agricultural land expansion. Mostly, we deal with this in a way, that we cut down all trees in an area we like. With this, we break the balance, which leads to changes in everyday processes as well as the decline of habitat and species richness. We can have two scenarios after clearing the land. One is, that there is too little water and another is, that there is too much water. In the latter example, the remaining plants are not able to absorb the amount of rainwater, leading to rising levels of underground water, suffocating the currently still present plants. When there is to little water present, the evaporation process still takes place, lifting the water (together with dissolved salts and minerals) to the surface (see how it looks like here). Because of these changes, the unadapted plants slowly die.
When the upper part of the trees are removed, the lower part begins decomposing, leading to empty areas, where wind and water erosion can occur (you can find a more detailed scheme of problems after deforestation here). Another big problem that is connected to farming is tractors. It is completely understandable, that in these hard working conditions the life without them is unimaginable. However, their weight has a big influence on the ecosystems, because it compresses the soil. When the soil is compressed, the water is unable to penetrate it and this leads to two things. One is bad living conditions for plants and the other is that there is a high level of erosion.
There is one more thing we do in agriculture that need broad lands and has a big effect on ecosystems, and this is livestock. We tend to put as many animals as possible on the land, which leads to compressing of the soil and overgrazing. In both cases, plants don’t have good living conditions (frequent damage done on plants, less available water, less soil, and nutrients etc.) and disappear from the area after some time.
How we try to prevent desertification?
I am not saying that every area, where a deforestation is made or where we have intensive farming is going to end as a desert, but it can be a start. Desertification is a growing problem and it affects the lives of many people. There are a lot of different ways they try to fight it. They build barriers to lower the wind erosion. With this, they lower the risk of people getting lung diseases as well as lower the level of injuries done to plants. This enables better growing conditions for them and increases the amount of produced food. To prevent water and soil loss, they dig canals. The rainwater then runs in the canal and slowly penetrates into the soil or slowly evaporates. With digging this kind of canals, the soil loss is also prevented.
Unfortunately, this process is very hard to stop, but until there are people prepared to face the problem and do something about it, we might stand a chance in fighting it. However, if we won’t change something in the way we manage the environment, this is a battle with no end and it’s quite obvious that we are on the losing side.