What is Desertification and why is it an issue??

Transcription

1 What is Desertification and why is it an issue?? - Desertification occurs due a decrease in vegetation. This can happen naturally due to a drought or can be caused by human activities. The lack of plants can cause changes to the land. Plants help shade the soil, so when plants are removed, the soil will be exposed to the sun and will dry out more quickly. The roots of plants often help hold soil in place. (12) -Many lands that were once covered in vegetation are now barren and dry deserts. This overall change is known asdesertification, which is the conversion of habitable and fertile land to uninhabitable desert. (12) The process of desertification is permanent and cannot be reversed naturally. Once the land becomes a desert, it will stay a desert. This is of great concern because as more land becomes desert, there is a reduction in the amount of fertile land that we as humans can depend on to grow our food. Due to these factors, it is extremely important to stop desertification from occurring and to save the land that is at risk. (12) Desertification is a fancy word for land that is turning to desert, begins Allan Savory in this quietly powerful talk (9) - Desertification and starvation go hand in hand (1) - It's estimated that 50 million people will be displaced by desertification in the next decade (3) - desertification, also called desertization, the process by which natural or human causes reduce the biological productivity of drylands (5) - the various processes that threaten all dryland ecosystems, including deserts as well as grasslands and scrublands. (5) - People are losing their homes b/c there is no food or water. It is causing cities to become populated (5) - A 2007 report by the United Nations University maintains that the lives of 100 to 200 million people are affected by desertification. The report also notes that this phenomenon may cause the displacement of about 50 million people by 2017, making it one of the most severe environmental challenges facing humanity. (5) - A picture of land in Africa shows the soil turned to dry,cracked, hard brown, flat ground that looks like it has a perfect repeated pattern. (5) - According to leading environmental experts, desertification is, in part, a natural process that accelerates and decelerates according to weather events, such as droughts, as well as broader fluctuations in the global climate. But many experts also contend thatdesertification has accelerated at an alarmingly high rate since the mid- 20th century, mainly due to human- induced land degradation caused by farming and livestock grazing. (7)

2 Human causes of desertification? Overgrazing & agricultural practices - Throughout the world, farmers and livestock owners are contributing directly to desertification by growing crops and grazing animals in an unsustainable manner. Poor farming techniques and overgrazing cause soil degradation in the vicinity of deserts, making it easier for deserts to expand. (7) - agricultural practices that destroy the soil structure, especially the use of unsuitable agricultural machinery; (2) - agricultural practices that result in the net export of soil nutrients, leading to loss of the soil fertility, such as cash- cropping; (2) - Unsustainable farming methods also contribute to soil degradation. Crop rotation, heavy composting and responsible use of chemical fertilizer ensure that the soil has enough organic imput to support vibrant micro- organisms. On the other hand, overuse of chemical fertilizers, failure to employ crop rotation and irresponsible irrigation practices rob the soil of the last of its nutrients. When topsoil is depleted of humus, it's either too loose or too compacted, both of which can lead to destructive erosion. (3) Grazing animals are just as bad. Grasses are essential to anchoring arid topsoil in a dryland region. When animals are allowed to graze recklessly, they remove all of the native grasses, exposing the topsoil to destructive erosion forces like winds and sudden thunderstorms. (3 - irrigated croplands: The main cause of declining biological productivity in irrigated croplands is the accumulation of salts in the soil. (5) - grazing land: The process of soil damage and loss often begins with the activities of grazing animals. Grazing livestock sometimes consume plants down to the ground. This activity weakens the individual plant; with a reduction in tissues capable of photosynthesis, its growth is greatly inhibited. In addition, livestock herds may trample and kill vegetation by walking to and from permanent water sources. Trampling destroys plant roots that bind the soil together. When rains come to those grazing lands, rivulets often form along the walking paths and wash away unprotected topsoil. Also, the repeated movement of herds over one section of the landscape can compact the soil, hindering the development of plant roots. (5) - Poor irrigation techniques on farms can also lead to desertification. If farmers use too much water or use water inefficiently, they will reduce the overall water supply in the area. This can lead to vegetation loss and eventually desertification. (12)

3 -Overgrazingoccurs when farmers allow livestock to graze to the point where they damage the vegetation. This can happen when farmers have too many livestock in a small area or when they keep livestock in an area for a long period of time. (12) Agriculture uses 85 percent of water in this region. It is common to misuse land by heavy irrigation in the Middle East. In the area droughts are more frequent, and contribute to the changing landscape. The overuse of water in agriculture is affecting the countries' already undersized water resources. (13) Deforestation Firewood is the fuel of choice for many people living in developing countries. This has led to unchecked clear- cutting of forests in dryland ecosystems. Trees play a crucial role in anchoring down topsoil and slowing down the force of winds. When too many trees are removed, windstorms and dust storms ensue.(3) - If plants are removed, the soil will have nothing protecting it, and it will be more susceptible to erosion by wind. This will reduce fertility of the land because the top layer of soil that will be blown away by wind is often the richest in nutrients. Once this top layer of soil is removed, the land will no longer be fertile and will be unable to support the growth of vegetation. Eventually, the land will become so dry and devoid of vegetation that it will be classified as a desert. (12) - Deforestation is the process of removing trees and transforming a forest into cleared land. This is often done to make room for farming or housing for the growing human population. Both overgrazing and deforestation can lead to desertification because they remove or damage the vegetation that is protecting the land and keeping it moist and fertile. (12) How can desertification be prevented/what s being done? - One picture shows Workers in Zhenglan County, China, plant trees on the fringes of a desert in order to limit future desert growth. According to many environmental experts, China will face a variety of serious desertification- related problems in the 21st century. (7) - One diagram that contains pictures shows the before and after difference of rehabilitation efforts on desertified land. The new land shows plants, soil not dry and patterned, and fields of green crops. (10) - Environmental experts say yes, but it will require a worldwide campaign to improve agricultural methods, regenerate plant life and conserve precious soil fertility. (3) - The first step is to replace destructive agricultural techniques at the grassroots level. Poor farming communities in developing countries need to be taught (3)

4 - Planting millions of trees in strategic locations could do wonders for halting the expansion of current deserts and preventing the creation of new ones. The Chinese government is currently planting a nearly 3,000- mile- long (4,828- kilometer- long) belt of trees along the edge of the Gobi desert to put the brakes on dust storms and prevent dune migration. A similar "green wall" is being considered along the frontier of the Sahara [source: Ford]. On a smaller scale, simply planting trees around fields will cut winds that contribute to erosion of topsoil. (3) Salt traps, which involve the creation of so- called void layers of gravel and sand at certain depths in the soil. Salt traps prevent salts from reaching the surface of the soil and also help to inhibit water loss. Irrigation improvements, which can inhibit water loss from evaporation and prevent salt accumulation. This technique involves changes in the design of irrigation systems to prevent water from pooling or evaporating easily from the soil. Crop rotation, which involves the alternation of different crops on the same plot of land over different growing seasons. This technique can help maintain the productivity of the soil by replenishing critical nutrients removed during harvesting. Rotational grazing, which is the process of limiting the grazing pressure of livestock in a given area. Livestock are frequently moved to new grazing areas before they cause permanent damage to the plants and soil of any one area. - Supporters of aggressively combating desertification contend that expansion of deserts is largely due to humans' irresponsible land use. For that reason, they say, it is humankind's responsibility to curb desertification before it wreaks further havoc on the international community. By raising public awareness about the issue, implementing sustainable land- management policies and replanting vegetation in areas threatened by desertification, people can effectively limit the growth of the world's deserts, proponents assert. (7) Why is this an important issue? - A 2006 U.N. conference on desertification in Tunisia projected that by 2020 up to 60 million people could migrate from sub- Saharan Africa to North Africa and Europe. (8) In Iran, villages abandoned because of spreading deserts or a lack of water number in the thousands. In Brazil, some 250,000 square miles of land are affected by desertification, much of it concentrated in the country's northeast. (8) In Mexico, many of the migrants who leave rural communities in arid and semiarid regions of the country each year are doing so because ofdesertification. Some of these environmental refugees end up in Mexican cities, others cross the northern border into

5 the United States. U.S. analysts estimate that Mexico is forced to abandon 400 square miles of farmland to desertification each year. (8) In China, desert expansion has accelerated in each successive decade since Desert scholar Wang Tao reports that over the last half- century or so some 24,000 villages in northern and western China have been abandoned either entirely or partly because of desert expansion. (8) - In the 1990 s the UN wanted to address the problem of desertification but many countries particularly developed nations without significant desert or dryland areas did not feel the need to deal with the problem. Now people who are affected by ths problem are moving into countreis not affected by it and there is not enough space for everyone to live. (7) - Some 10 to 20% of drylands are already degraded, and ongoing desertification threatens the world s poorest populations and the prospects of poverty reduction. Therefore, desertification is one of the greatest environmental challenges today and a major barrier to meeting basic human needs in drylands. (1) - Across the world, desertification affects the livelihoods of millions of people who rely on the benefits that dryland ecosystems can provide. (1) - In 2000, drylands, which occupy 41% of Earth s land area, were home to a third of the human population, or 2 billion people. (1) - Consequently, the effects of desertification are extremely serious and often dramatic for the poor populations of developing countries. (2) - Finally, desertification exacerbates the effects of climatic (drought) and political (war) disasters, regularly leading to the suffering and death of hundreds of thousands of people throughout the world. (2) - b/c it affects Roughly half of Earth s ice- free land surface approximately 52 million square km (about 20 million square miles) is drylands, and these drylands cover some of the world s poorest countries. The United Nations Environment Programme (UNEP) notes that desertification has affected 36 million square km (14 million square miles) of land and is a major international concern. (5) - But the effects of desertification are also felt by millions of people living far from the immediate dryland zones. One effect is the mass migration of people from rural areas to already overpopulated cities. This contributes to sprawling slums that are breeding grounds for disease. It's estimated that 50 million people will be displaced by desertification in the next decade [source: PeopleandPlanet.net]. (3) Freshwater scarcity, which already affects 1-2 billion people, is expected to increase,

6 causing even greater stresses in drylands. If nothing is done to reduce this scarcity, it will result in a worsening of desertification. (1) - "What we do is that when the sand moves and buries our homes and farms and even our wells, we simply keep retreating southwards," says Aminu Mahmud, a resident of northern Nigeria who has lost several homes as a result of the Sahara's growth. "The desert's unrelenting onslaught is pushing us further away from our original homes and it seems there's absolutely nothing we can do about it," he asserts. Environmentalists say that many other countries are undergoing experiences similar to that of Nigeria, withdesertification now threatening roughly two- thirds of the world's agricultural lands (7) SOURCES: 1. (website) 2. (website) 3. on1.htm (website) 4. (map) 5. (image) 6. My brain 7. Desertification. Issues & Controversies. Infobase Learning, 6 July Web. 16 Nov < (Facts on File database) (image) 8. Brown, Lester R. "Spread of Deserts, Falling Water Tables Create Refugees." Global Information Network. 23 Aug. 2011: n.p. SIRS Issues Researcher. Web. 16 Nov (SIRS database) 9. erse_climate_change (video) desertification.com/images/uploads/shigangdun- 1.png (image before and after comparison of rehabilitation of desertified land)

7 11. access/asia/pages/alltext.aspx (website) caused- by- human- activity.html in- crisis- middle- east