Land Desertification: Its Causes and Effects

Land Desertification is devastating farmland and the lives of millions of people around the world. While its drivers are a mixture of natural and human activities, the process is well understood and can be mitigated against, if the will is there.

In the following article, we'll explore what desertification is and highlight how it occurs, where it is occurring, and assess how bad the damage is to date. This is not intended to be a comprehensive guide and is merely an overview of our current understanding of the problem.

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What is land desertification and its causes?

Land desertification, as the name suggests, is a process of land degradation whereby a relatively dry area gradually becomes a desert. This usually involves the loss of any bodies of water and vegetation the habitat once possessed.

It is actually defined by the United Nations Convention to Combat Desertification (UNCCD)  as: "land degradation in dryland areas due to various factors, including climatic variations and/or human activity."

In this regard, land desertification is usually linked to images of deserts moving across landscapes, encroaching on farmlands, and starving vulnerable populations.

But, desertification is one element in a wider issue with land degradation around the world. For this reason, the 2018 World Atlas of Desertification (WAD) describes it as: -"land degradation leads to long-term failure to balance demand for and supply of ecosystem goods and services."

WAD, published by the Joint Research Centre (JRC), provides a comprehensive, evidence-based assessment of land degradation around the world. It is also a useful tool for decision-makers to prioritize problem areas and adopt, where possible, corrective measures to halt issues like desertification. 

The JRC's Commissioner for Education, Culture, Youth and Sport, Tibor Navracsics said:

"Over the past twenty years, since the publication of the last edition of the World Atlas of Desertification, pressures on land and soil have increased dramatically. To preserve our planet for future generations, we urgently need to change the way we treat these precious resources. This new and much more advanced edition of the Atlas gives policymakers worldwide comprehensive and easily accessible insights into land degradation, its causes and potential remedies to tackle desertification and restoring degraded land."

Causes of land desertification are a combination of natural phenomena and human activities. These include things like climate change, deforestation, and overexploitation of soil by farming.

According to sites like greenfacts.org, the current major factors that contribute to or drive desertification are: -

Source: Land Degradation Neutrality Transformative Action, tapping opportunities, Global Mechanism of the UNCCD, 2016.

It should be noted that desert formation is a natural part of Earth's systems but it can be perturbed or accelerated by human activities, notably animals husbandry (overgrazing for example), and agriculture. So-called "soil death", or the process of rampant and unchecked nutrient depletion in soils, is one of the main driving forces for desertification. 

"Desertification is a significant global ecological and environmental problem with far-reaching consequences on socio-economic and political conditions." - Wikipedia.

What is the process of desertification?

Land desertification, as we have already seen, is the gradual, yet continuous, process of ecosystem degradation in an affected area. During this process, plants and animals, and geological resources like water and soil, are stressed beyond their ability to adapt and change. 

The process occurs gradually and the causes for it are well understood. For this reason, it is possible for it to be avoided or reversed before the problem gets too serious. 

Desertification is characterized by: -

- The progressive loss of mature, stabilizing vegetation in the ecosystem;

- Loss of agricultural crop cover during periods of drought or economic infeasibility, and;

- A resulting loss of unconsolidated topsoil.

This process is called deflation. 

With the loss of vegetation, wind, and water, winnow out the fine-grained silt and clay particles from the soil. This can lead to dramatic dust storms like the 1930's Dust Bowl in the American mid-west, and other parts of the world.

These were essentially composed of blowing topsoil.

If the area in question undergoes continuous irrigation, it can complicate issues further by increasing the remaining soil's acidity. This leads to contamination of groundwater and does little, if anything, to reverse any loss in crop productivity. 

The final, often irreversible phase sees ongoing wind and water erosion leading to the development of gullies and sand dunes across the affected land surface. At this point, the land has become inhospitable to most vegetative and animal life.

How much land is affected by desertification?

 According to the 2018 World Atlas of Desertification (WAD) population growth and changes in human consumption patterns have resulted in unprecedented pressures being applied to Earth's natural resources. To date, desertification has resulted in (information courtesy of reliefweb.int and WAD): -

- Over 75% of the Earth's land area is already degraded, and over 90% could become degraded by 2050.

- Globally, a total area half of the size of the European Union (4.18 million km²) is degraded annually, with Africa and Asia being the most affected.

- The economic cost of soil degradation for the EU is estimated to be in the order of tens of billions of euros annually.

- Land degradation and climate change are estimated to lead to a reduction of global crop yields by about 10% by 2050. Most of this will occur in India, China, and sub-Saharan Africa, where land degradation could halve crop production.

- As a consequence of accelerated deforestation, it will become more difficult to mitigate the effects of climate change

- By 2050, up to 700 million people are estimated to have been displaced due to issues linked to scarce land resources. The figure could reach up to 10 billion by the end of this century.

It should also be noted that while land degradation, and desertification, are a global issue, the effects are local and require localized remediation. Groups like the UNCCD stress the need for greater commitment and more effective cooperation at the local level to stop the loss of habitat and stave off potential catastrophe for societies around the world.

Where is desertification happening in the world?

At present, desertification is affecting many parts of the world. It is most notable, however, in India, China, and sub-Saharan Africa. These areas share the characteristic of being drylands. 

Drylands comprise around 40-41% of the Earth's total land surface and are occupied by around 2 billion people. Some estimates show that 10–20% of drylands are already degraded to date.

"The total area affected by desertification being between 6 and 12 million square kilometers, that about 1–6% of the inhabitants of drylands live in desertified areas, and that a billion people are under threat from further desertification." - Wikipedia.

But more temperate regions, like Europe, are not immune to this problem. According to the WAD, EU nations have around 8% of their territory affected by desertification. The main areas of concern are Southern, Eastern and Central Europe.

These regions comprise around 14 million hectares (140,000 km2) and show high sensitivity to desertification. Under definitions set by the UNCDD, thirteen Member States have declared themselves affected by desertification.