Causes of desertification Desertification is the process of land turning into desert as the quality of the soil declines over time. The main causes of desertification include: Population growth - the population in some desert areas is increasing. In places where there are developments in mining and tourism, people are attracted by jobs.
An increased population is putting greater pressure on the environment for resources such as wood and water. Removal of wood - in developing countries, people use wood for cooking.
As the population in desert areas increases, there is a greater need for fuel wood. Although they are often used interchangeably, the difference lies in the human influence on the process. In desertisation, the causes of deterioration are strictly natural, as in the case of the Sahara mentioned above, but in desertification, although natural causes also play a role, human activities are a determining factor.
Deforestation , causes of which go beyond tree felling, which increases the risk of fires, among others. Poor agricultural practices, from not rotating crops to unprotected soils or chemical fertiliser and pesticide use, etc.
Overexploitation of natural resources as a consequence, for example, of irresponsible management of vegetation or water. Bad livestock practices, such as overgrazing, which severely erode the land and prevent the regeneration of vegetation. The areas of the world most vulnerable to desertification and why. Drylands cover about half of the earth's ice-free land surface and many of them belong to the world's poorest countries, which exacerbates the consequences:. Loss of biodiversity by worsening the living conditions of many species.
Food insecurity due to crop failure or reduced yields. The loss of vegetation cover and therefore of food for livestock and humans. Loss of forest cover , with a corresponding shortage of wood resources.
The decrease in drinking water reserves due to the loss of aquifers. According to the United Nations Convention to Combat Desertification, the lives of million people are already affected by desertification and up to million could be displaced climate migrations by desertification by , making it one of the most serious environmental problems facing humanity.
Among the Sustainable Development Goals SDGs adopted by the UN is SDG 15 Life of terrestrial ecosystems , which aims to protect, restore and promote the sustainable use of terrestrial ecosystems, sustainably manage forests, stop and reverse land degradation, combat desertification and stop biodiversity loss. The solution at the local level to curb desertification is sustainable management of natural resources, especially the conservation of fertile soils and water resources. This is an area that could produce 20m tonnes of grain annually.
This has a considerable financial impact. Loss of livestock, reduced crop yields and declining food security are very visible human impacts of desertification, says Stringer:.
Another impact of desertification is an increase in sand and dust storms. Dust storms can have a huge impact on human health, contributing to respiratory disorders such as asthma and pneumonia, cardiovascular issues and skin irritations, as well as polluting open water sources.
They can also play havoc with infrastructure, reducing the effectiveness of solar panels and wind turbines by covering them in dust, and causing disruption to roads, railways and airports. Adding dust and sand into the atmosphere is also one of the ways that desertification itself can affect the climate, says Kimutai. Dust particles in the atmosphere can scatter incoming radiation from the sun, reducing warming locally at the surface, but increasing it in the air above.
They can also affect the formation and lifetimes of clouds, potentially making rainfall less likely and thus reducing moisture in an already dry area. Soils are a very important store of carbon. This process also makes nutrients in the soil available for plants to use as they grow. Soil erosion in Kenya.
And typically, respiration declines with decreasing soil moisture to a point where microbial activity effectively stops. While this reduces the CO2 the microbes release, it also inhibits plant growth, which means the vegetation is taking up less CO2 from the atmosphere through photosynthesis. Overall, dry soils are more likely to be net emitters of CO2.
So as soils become more arid, they will tend to be less able to sequester carbon from the atmosphere, and thus will contribute to climate change. Other forms of degradation also generally release CO2 into the atmosphere, such as deforestation , overgrazing — by stripping the land of vegetation — and wildfires.
But coming up with a robust global estimate for desertification is not straightforward, explains Kimutai:. The multiplicity and complexity of the processes of desertification make its quantification even more difficult.
Studies have used different methods based on different definitions. And identifying desertification is made harder because it tends to emerge relatively slowly, adds Michaelides:.
By the time it is detected, it may be hard to halt or reverse. Status of desertification in arid regions of the world.
Taken from Dregne, H. The GLASOD project was itself based on expert judgement, with more than soil and environmental scientists contributing to regional assessments that fed into its global map, which it published in It categorised the degradation into chemical red shading , wind yellow , physical purple or water blue. Shading indicates type of degradation: chemical red , wind yellow , physical purple and water blue , with darker shading showing higher levels of degradation.
Source: Oldeman, L. As the report puts it:. A single global map of land degradation cannot satisfy all views or needs. The parts of the world with the most potential issues shown by orange and red shading — such as India, Pakistan, Zimbabwe and Mexico — are thus identified as particularly at risk from degradation.
Shading indicates the number of coincident risks. The areas with the fewest are shown in blue, which then increase through green, yellow, orange and the most in red. Credit: Publication Office of the European Union. As desertification cannot be characterised by a single metric, it is also tricky to make projections for how rates of degradation could change in the future. In addition, there are numerous socio-economic drivers that will contribute. For example, the number of people directly affected by desertification is likely to increase purely because of population growth.
The impact of climate change on aridity is also complicated. A warmer climate is generally more able to evaporate moisture from the land surface — potentially increasing dryness in combination with hotter temperatures.
These policies include a shift to low-carbon energy technologies and the deployment of carbon capture and storage. In RCP4. By , global temperatures are likely to rise by C above pre-industrial levels. However, climate change will also affect rainfall patterns, and a warmer atmosphere can hold more water vapour, potentially increasing both average and heavy rainfall in some areas.
There is also a conceptual question of distinguishing long-term changes in the dryness of an area with the relatively short-term nature of droughts. In general, the global area of drylands is expected to expand as the climate warms.
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