Desertification

4. What are the major causes of desertification?

• 4.1 What social, economic, and policy factors can contribute to desertification?
• 4.2 Does globalization play a role in desertification?
• 4.3 How can land use affect desertification?

"Desertification is caused by a combination of factors that change over time and vary by location. These include indirect factors such as population pressure, socioeconomic and policy factors, and international trade as well as direct factors such as land use patterns and practices and climate-related processes."

Fig 1.1 How developments in drylands can contribute to or prevent desertification

These factors lead to decreased land productivity and a downward spiral of degradation and poverty (Figure 1.1). Where conditions permit, dryland populations can avoid degradation by improving their agricultural and grazing practices in a sustainable way

To counter the problems effectively, it is important — but difficult — to distinguish between effects resulting from natural conditions and those caused by management decisions as well as economic and policy factors.

4.1 What social, economic, and policy factors can contribute to desertification?

Policies leading to an unsustainable use of resources and the lack of adequate infrastructures are major contributors to land degradation. Agriculture can play either a positive or a negative role, depending on how it is managed. Local institutions can contribute to preventing desertification by allowing land users to manage and use ecosystem services more effectively through enhanced access to productive land, capital, labor, and technology.

Policies favoring sedentary farming over nomadic herding can contribute to desertification. The majority of dryland areas (65%) are rangelands that are more suited to sustainable grazing than crop production. Sedentarizing nomads and limiting their movements leads to desertification because it reduces their ability to adjust their economic activities in the face of stresses such as droughts.

When farmers and herders lose control or long-term security over the land they use, the incentives for maintaining environmentally sustainable practices are lost, and this can greatly contribute to desertification. Control and security does not necessarily require private property rights; and collective and community-based management practices have proven quite effective. Unappropriate decision making can cause problems of water scarcity, groundwater depletion, soil erosion, and salinization. More...

4.2 Does globalization play a role in desertification?

The process of globalization can either contribute to desertification or help prevent it. Globalization creates stronger links between local, national, sub-regional, regional, and global factors related to desertification. Studies have shown that, in dryland areas, trade liberalization, macroeconomic reforms, and a focus on raising agricultural and livestock production for exports can sometimes lead to desertification. In other cases, enlarged markets can also contribute to successful agricultural improvements.

Global trade regimes and linked government policies can influence food production and consumption patterns significantly and affect directly or indirectly the capacity of dryland ecosystems to recover from stresses. Selective production and export subsidies, such as those in the European Union and the U.S., stimulate overproduction of many food crops in those countries. This can drive down prices on the international market, and have often undermined the livelihoods of many food producers in poorer countries. However, removing international trade barriers without regulation at national level may also encourage unsustainable agricultural practices. More...

4.3 How can land use affect desertification?

Water erosion and reduced soil conservation in semi-arid Burkina Faso negatively affects ecosystem services
Source: MA

Historically, dryland livelihoods have been based on a mixture of hunting, gathering, farming, and herding. This mixture varied with time, place, and culture, since the harsh conditions forced people to be flexible in their use of the land. Population pressure, however, has led to the extension of cultivated lands in dryland areas. In some cases this has caused desertification and conflicts between herders and farmers who claimed access to the same land. In other cases, when policy and market conditions were favorable, it led to positive interactions between the two groups.

In some areas, the increase in cultivation has been driven by increased irrigation which has often been unsustainable. Irrigation can cause environmental problems such as waterlogging, salinization, water pollution, eutrophication, and excessive groundwater use. On the whole, irrigation has had a strong impact on inland waters, causing a decline in biodiversity and further desertification.

Frequent and intensive fires can contribute to desertification when they affect natural vegetation. However, limited controlled fires can play an important role in the management of dryland herding and farming systems, promoting nutrient cycling and forage quality. More...