From a worldwide perspective, desertification refers to the land degradation in some regions caused by various factors, including climate variability and human activities. Specifically, desertification emerges and develops in arid, semi-arid and sub-humid regions (areas with the ratio of annual precipitation to potential evapotranspiration between 0.05 and 0.65, but excluding polar and sub-polar regions). In the late 1960s and early 1970s, years of severe drought in Sub-Saharan Africa led to unprecedented disasters. As a result, the international community paid close attention to the land degradation in the dry areas all over the world, and the term desertification has been widely spread. At the World Conference on Environment and Development in June 1992, combating desertification was listed as a priority area for development and action by the international community. In addition, June 17, the global Day to Combat Desertification and Drought was created and adopted by the United Nations General Assembly in 1995, using for propaganda to the public.

Global Distribution of Desertification Areas

The world’s deserts are mainly distributed in the range from subtropical to temperate regions on both sides of the equator, mainly between 10 degrees to 50 degrees north and south latitude. From the Sahara in North Africa, through the Arabian Peninsula in southwest Asia, Iran, northern India, Central Asia to northwest China and Mongolia, an almost continuous, as long as 13,000 kilometers of vast arid desert belt was formed, accounting for 67% of the world’s desert area. The ten major deserts, including the Sahara Desert, Arabian Desert, Libyan Desert, Australian Desert, Gobi Desert, Patagonia Desert, Rubhari Desert, Kalahari Desert, Great Sand Desert and Taklimakan Desert, have a significant impact on nature, economy and society around the world. In addition to the ten deserts mentioned above, there are also some smaller regional deserts with the basic characteristics similar to that of large deserts, such as drought, little rain, bare land, and heavy sandstorms, which also strongly affect the local natural and social economic development.

Causes And Consequences of Desertification

Desertification is caused by both natural and human factors. In detail, drought, flood, wind erosion, water erosion and other natural processes are closely related to climate change. Besides, human factors are the fundamental causes of modern desertification and unreasonable land use is the driving force of desertification. In countries where desertification is spreading seriously, land use has the following problems. On one hand, local people overgrazed, destroying vegetation and interfering with plant communities, especially in dry years and flood seasons; or they cut down and destroyed the trees, resulting in deforestation and soil erosion. On the other hand, the local residents blindly reclaimed and abandoned the land, resulting in frequent damages to the stability of the ecosystem in the dry seasons; the uncontrolled population growth is also an important cause of land degradation and desertification. Moreover, improper irrigation systems, including indiscriminate construction of reservoirs and irrigation channels, have caused soil salinization, land degradation and drying up of the downstream of inland rivers. Thus, the fragile arid land ecosystems can only be exploited limitedly. Once the ecological limit is exceeded, the destructive development will lead to the decline of productivity in the short term, and it will bring disastrous harms to human beings in the long term.

One third of the world’s arid regions are on the edge of desertification, a problem that affects more than 900 million people in more than 100 countries and causes economic losses of US dollar 42 billion a year. The world’s large-scale desertification is concentrated in Africa and Asia, residents in these area accounts for 74% of the earth’s population. In Africa, the Sahara Desert is moving northward, shrinking the living space of people in the northern countries of the continent. The west African savanna is a vast area extending from the south of the Sahara Desert, north of the African savanna, along the Atlantic coast to the western foothills of the Ethiopian Plateau. Here, farming and herding overlap. From Senegal and Mauritania in the west to Sudan, Ethiopia and Somalia in the east, growing populations and increasing livestock demand natural resources made an expanding acreage of land turn into desert.

International Practice in Combating Desertification

There are three types of successful models for combating desertification internationally. First, the government-led model has been applied by the United States, Canada, Germany and Romania. Secondly, the type of technology-oriented has been used by Israel, the United Arab Emirates and India. The third type is industry-led model and typical countries are Australia, Egypt and Iran.

Adopting the government-led model, these countries believe that desertification control is a macroscopic problem that cannot be solved by individuals, enterprises and organizations alone. The United States government has played a leading role in preventing and controlling desertification, controlling production and protecting land from the macro perspective. The federal government has issued a series of policies and decrees, and the states have also formulated feasible land development and desert control laws, such as the Masso Shoal and Tennessee River Basin Management Act in 1933, and the Regional Redevelopment Act in 1961. These laws not only improved the legal system of the United States, but also provided a strong policy and legal guarantee for the implementation of the western development and desert control strategy of the United States. At the same time, the United States government also established the Soil Conservation Bureau to encourage states to implement soil conservation measures, and finally achieved satisfactory results.

Countries that applying technology-oriented model consider that the combination of advanced and applicable science and technology with executable measures could accelerate the control of desertification and achieve desirable benefits. There are a number of countries have given full play to the role of science and technology in combating desertification. The Stanberg Desert Research Institute in Israel not only studies projects directly related to desertification, but also studies many indirect projects, including solar and wind energy development and utilization, sewage treatment and utilization, desert architecture and urban dust control. Moreover, the institution researches on geothermal and brackish water utilization, water saving and water resource management, biotechnology, facility agriculture and more than 20 professional fields.

The Industrial-led model is agreed by countries that regard desertification control could not only improve the survival and ecological environment, but also develop production and promote economic development. Therefore, Australia makes advantages of the resources of desertification areas, supports the development and utilization of new energy, ecological tourism and medical plants, and speeds up the transformation and application of high-tech achievements, so that the process of desertification prevention and control becomes an effective method for farmers and herdsmen to get rid of poverty and become rich.

Enlightenments For Global Desertification Control Measures

The basic experience of international desertification control can be summarized as follows. First, governments should place desertification prevention and control on the list of major issues, formulating and improving relevant laws and regulations. Secondly, local authorities and agencies should effectively manage desertification control actions and pay attention to training in related techniques and capabilities. Third, government departments should propose preferential policies to promote water conservation and rational use of land, and attach importance to ecological construction. Fourth, they should adopt comprehensive measures to combat desertification, supported by science and technology. In addition, the government sectors should seek financial support and raise funds for desertification control through multiple channels. Finally, the support of non-governmental organizations and the international community are also practical help for actively combating desertification.

By Xin Wang