User:Wenjunh

Desertification: Desertification is a process by which land becomes increasingly dry until almost no

vegetation grows on it, making it a desert. The desert mentioned here is not that desert caused by dry climate, but

that land where plants cannot grow. Desertification can be natural. As a natural phenomenon, desertification is caused by the movement of the dry belt

of the earth. However, today most desertification around the world is caused by the increasing of population and

other reasons.

Current situation

 * world: Desertification is the degradation of land in arid and dry sub-humid areas,

resulting primarily from human activities and influenced by climatic variations.
 * China: According to the data released by State Forestry Administration of China:

''the area of decertified lands in China, which are found in more than 30 administrative regions, is more than 18%

of the area of the whole country. There is a “decertified arc” in the west to Helen Mountains. The desertification

influences more than 70 million people, most of which are the poorest in the country. Although Chinese government

has never stopped handling the negative effects of desertification and diverse solutions has been tried to stop

desertification, the situation still deteriorates, the decertified area increases by 2100 km2 since 1980s. In

recent years, dust storm originated in West China periodically attacks Korean peninsula and Japan.

''[http://desertification.wordpress.com/2007/08/18/desertification-in-china-can-sandstorms-be-stopped-google-alert

-schreiners-media-landscape/]

Loss
Some analyses exhibit that desertification results in extremely financial cost, which is approximately 14% of China

’s GPA. This cost only includes direct and indirect costs and excludes the unpredictable lost due to the decrease

of species richness. UN Environment Program considers that the financial the later is 2 to 3 times more than the

former.

Population

 * Increasing of population: CNN Eco solution: ''Rapid population growth has put enormous pressure on

agricultural systems that have been pushed towards unsustainable farming practices in order to cope with demand. In

China livestock numbers have nearly doubled in the last 30 years, from around 200 million in the early 1970's, to

427 million in 2002. ''
 * The affluence of human activity: People in China need lots of trees every year. They cut down lots of trees.

And they also change forest into agriculture use. So the land has become drier and drier, that's how

desertification is formed.

climate change

 * The change of climate: The change of globle climate has changed the percipitation around the world. The dry

erea become drier,so the plant's living enviroment become worse.

measures of other countries

 * EFEDA: European Field Experiment in a Desertification-threatened Area: Measurements were made from the

microscale (e.g. measurements on single plants) up to a scale compatible with the grid size of global models. For

this purpose three sites were selected 70 km apart and heavily instrumented at a scale in the order of 30 km2.

Aircraft missions, satellite data and movable equipment were deployed to provide a bridge to the larger scale. This

paper gives a description of the experimental design along with some of the preliminary results of this successful

experiment.
 * Department of Geography at U of Maryland at college park: We have demonstrated that reductions of potential

primary production in drylands is a reliable indicator of the "diminution or destruction of the biological

productivity of the land" - the UN Conference on Environment and Development definition of desertification (UNCED,

Brazil 1992). The earth observation satellite record of the past 25 years is being used to estimate net primary

production, thus providing an objective measurement of desertification. The results are the first objective map of

current degradation in the world's drylands.

Reference
Desertification: How to stop the shifting sands



Reign of sand: Inner Mongolia

UNEP. Map of Desertification Hazards., United Nations Environment Programme, Rome (1984).

Desertification

中国沙漠及土地沙漠化图(Map of Chinese dessert and desertification)