Desertification is defined as the process in which fertile land becomes desert. With rising temperatures due to global warming, the rate of desertification is increasing. Each year, 12 million hectares are lost to desertification, which equates to 23 hectares per day. However, what is causing this shocking spready of hostile environment that affects 1.5 billion people globally. The three factors I will took at here are human activity, metrological and hydroloygical.
The first factor is metrological influences.
This refers to the weather and climate of a region. There are a few ways in which it can cause desertification. Firstly, changes to circulation patterns in the ocean can cause the rainey season to be delayed or fail altogether. This is because, it can bring areas high pressure with the trade winds over an area. This high pressure stops evaporation and therefore precipitation.
Secondary, atmospheric circulation can bring cool air over hot areas from the sea as well as high pressure. This cool air, thanks to global warming, is being heated and therefore is a factor of desertification. It is also affecting the climate of each climate cell, especially in the Hadley cell where deserts are mainly located, which has bad repercussions in itself.
Finally, are jet streams. This is a bit like atmospheric circulation. Along with trade winds, jet streams carry weather fronts around the world. Disruption to them causes weather systems to be diverted and in some cases wet weather fronts missing areas causing dried up land equalling desertification.
The second factor is Hydrological factors
This refers to impacts of low precipitation to freshwater/ inland water systems like rivers, lakes and reservoirs. The lack of precipitation is started by the metrological factors like high pressure due to atmospheric and oceanic circulation disruption and jet streams, which causes a chain of events leading to a lack of fresh water inland. This has many negatives for the land and native animals and humans.
It impacts groundwater and resouvoir levels to an almost dried up point. Most animals in this biome rely on oasis' as their only source of water. If these dry up due to extreme desertification, then they will die. Also, rural communities rely on these sources to drink and without them, they will have to revert to dirty, muddy water sources that can cause the spread of cholera and typhoid.
It affects the moisture in the soil. Plants will not be able to get the water they need to survive so will die. This is a concern in itself but when they are crops and someone is depending on them for income, and in the cause of subsistence farming, food it becomes a bigger problem. This could lead to migration as farmers will no longer be able to farm on this infertile land and have to migrate to different problems.
Finally, is human activity.
This branches into many categories. Firstly, deforestation. With demand for lumber in MEDC's and sources of fuel in LEDC's, companies chop down the trees and vegetation. By doing this, it removes nutrients and water storages from the the ground. A lack of moisture leads to the ground drying up and the end result is a desert-like area. Slash and burn -a popular deforestation method- is the worst and not only does it kill vegetation, it instantly dries the land. Before, it was a long process, now it is instantaneous.
Farmers use sprays and fertilisers to enhance the growth of plants. They are pumped out by irrigators. However, there is a large area of land that is not covered by these fertilisers. Therefore, the soil in these areas will be without nutrients or water so will dry up leaving areas with crops and desert all around.
Finally, is the use of dams. There are 57,000 dams in the world; 300 major ones. One the one hand they are good because they produce hydro-electricity which combats global warming. However, the clog up rivers so eventually, downstream the river becomes non existent. With no moisture in the soil, deserts start to form. It also has some other bad effects like disrupting the migration of fish and that means no food or water for animals or humans that rely on it to survive.
In conclusion, desertification is causing a real threat to the world. However, it is being caused mainly by us as humans. There needs to be change whether that is in bans, laws or education, something has got to give otherwise our whole land mass in the tropics will become a desert.
