Desertification

Desertification is a type of land degradation in drylands in which biological productivity is lost due to natural processes or induced by human activities whereby fertile areas become increasingly more arid.[2] It is the spread of arid areas caused by a variety of factors, such as through climate change (particularly the current global warming)[3] and through the overexploitation of soil through human activity.[4]

Not to be confused with Decertification or Desertion.
U.S. Department of Agriculture map from 1998 showing global desertification vulnerability
Lake Chad in a 2001 satellite image, with the actual lake in blue. The lake lost more than 90% of its surface area between 1987 and 2005.[1]

Throughout geological history, the development of deserts has occurred naturally; however, when deserts emerge due to unchecked depletion of nutrients in soil that are essential for it to remain arable, then a virtual "soil death" can be spoken of,[5] which traces its cause back to human overexploitation. Desertification is a significant global ecological and environmental problem with far-reaching socio-economic and political consequences.[6]

Definitions of words

As recently as 2005, considerable controversy existed over the proper definition of the term "desertification." Helmut Geist (2005) identified more than 100 formal definitions. The most widely accepted[7] of these was that of the Princeton University Dictionary which defined it as "the process of fertile land transforming into desert typically as a result of deforestation, drought or improper/inappropriate agriculture".
However, this original understanding that desertification involved the physical expansion of deserts has been rejected as the concept has evolved.[8] Desertification has been neatly defined in the text of the United Nations Convention to Combat Desertification (UNCCD) as "land degradation in arid, semi-arid and dry sub-humid regions resulting from various factors, including climatic variations and human activities."[9]

There exists also controversy around the sub-grouping of types of desertification, including, for example, the validity and usefulness of such terms as "man-made desert" and "non-pattern desert".[10]

History

The world's most noted deserts have been formed by natural processes interacting over long intervals of time. During most of these times, deserts have grown and shrunk independent of human activities. Paleodeserts are large sand seas now inactive because they are stabilized by vegetation, some extending beyond the present margins of core deserts, such as the Sahara, the largest hot desert.[11]

Historical evidence shows that the serious and extensive land deterioration occurring several centuries ago in arid regions had three epicenters: the Mediterranean, the Mesopotamian Valley, and the Loess Plateau of China, where population was dense.[12][13]

The earliest known discussion of the topic arose soon after the French colonization of West Africa, when the Comité d'Etudes commissioned a study on desséchement progressif to explore the prehistoric expansion of the Sahara Desert.[14]

Areas affected
Sun, moon, and large telescopes above Chile's Atacama Desert[15]

Drylands occupy approximately 40–41% of Earth's land area[16][17] and are home to more than 2 billion people.[17] It has been estimated that some 10–20% of drylands are already degraded, the total area affected by desertification being between 6 and 12 million square kilometres, that about 1–6% of the inhabitants of drylands live in desertified areas, and that a billion people are under threat from further desertification.[18][19]

As of 1998, the then-current degree of southward expansion of the Sahara was not well known, due to a lack of recent, measurable expansion of the desert into the Sahel at the time.[20]

The impact of global warming and human activities are presented in the Sahel. In this area the level of desertification is very high compared to other areas in the world. All areas situated in the eastern part of Africa (i.e. in the Sahel region) are characterized by a dry climate, hot temperatures, and low rainfall (300–750 mm rainfall per year). So, droughts are the rule in the Sahel region.[21] Some studies have shown that Africa has lost approximately 650,000 km² of its productive agricultural land over the past 50 years. The propagation of desertification in this area is considerable.

Sahel region of Mali

Some statistics have shown that since 1900 the Sahara has expanded by 250 km to the south over a stretch of land from west to east 6,000 km long.[22][23] The survey, done by the Research Institute for Development, had demonstrated that this means dryness is spreading fast in the Sahelian countries. 70% of the arid area has deteriorated and water resources have disappeared, leading to soil degradation. The loss of topsoil means that plants cannot take root firmly and can be uprooted by torrential water or strong winds.[24]

The United Nations Convention (UNC) says that about six million Sahelian citizens would have to give up the desertified zones of sub-Saharan Africa for North Africa and Europe between 1997 and 2020.[24]

Lake Chad, located in the Sahel region, has been hit particularly hard by this phenomenon. The cause of the lake drying up is due to irrigation withdrawal and the annual rainfall dropping.[25] The lake has shrunk by over 90% since the 1987, displacing millions of inhabitants. Recent efforts have managed to make some progress toward its restoration, but it is still considered to be at risk of disappearing entirely.[26][1]

Another major area that is being impacted by desertification is the Gobi Desert. Currently, the Gobi desert is the fastest moving desert on Earth; according to some researchers, the Gobi Desert swallows up over 1,300 square miles (3,370 km²) of land annually. This has destroyed many villages in its path. Currently, photos show that the Gobi Desert has expanded to the point the entire nation of Croatia (about 4 million[27]) could fit inside its area.[28] This is causing a major problem for the people of China. They will soon have to deal with the desert as it creeps closer. Although the Gobi Desert itself is still a distance away from Beijing, reports from field studies state there are large sand dunes forming only 70 km (43.5 mi) outside the city.[29]

South America is another area affected by desertification, as 25% of the land is classified as drylands. In Argentina specifically, drylands represent more than half of the total land area, and desertification has the potential to disrupt the nation's food supply.[30]

In Mongolia, around 90% of grassland is considered vulnerable to desertification by the UN. An estimated 13% of desertification in Mongolia is caused by natural factors, the rest is due to human influence particularly overgrazing and increased erosion of soils in cultivated areas. The area of Mongolian land covered by sand has increased by 8.7% over the last 40 years. These changes have accompanied the degradation of 70% of Mongolian pasture land.[31] As well as overgrazing and climate change, the Mongolia government listed forest fires, blights, unsustainable forestry and mining activities as leading causes of desertification in the country.[32] A more recent study also reports overgrazing as a leading cause of desertification as well as the transition from sheep to goat farming in order to meet export demands for cashmere wool. Compared to sheep goats do more damage to grazing lands by eating roots and flowers.[33]

Effects

Sand and dust storms

There has been a 25% increase in global annual dust emissions between the late nineteenth century to present day.[34] The increase of desertification has also increased the amount of loose sand and dust that the wind can pick up ultimately resulting in a storm. For example, dust storms in the Middle East “are becoming more frequent and intense in recent years” because “long-term reductions in rainfall promot[ing] lower soil moisture and vegetative cover”.[35]

Dust storms can contribute to certain respiratory disorders such as pneumonia, skin irritations, asthma and many more.[36] They can pollute open water, reduce the effectiveness of clean energy efforts, and halt most forms of transportation.

Dust and sand storms can have a negative effect on the climate which can make desertification worse. Dust particles in the air scatter incoming radiation from the sun. The dust can provide momentary coverage for the ground temperature but the atmospheric temperature will increase. This can disform and shorten the life time of clouds which can result in less rainfall.[37]

Food security

Global food security is being threatened by desertification and overpopulation. The more the population grows, the more food that has to be grown. The agricultural business is being displaced from one country to another. For example, Europe on average imports over 50% of its food. Meanwhile, 44% of agricultural land is located in dry lands and it supplies 60% of the world's food production. Desertification is decreasing the amount of sustainable land for agricultural uses but demands are continuously growing. In the near future, the demands will overcome the supply.[38]

Vegetation patterning

As the desertification takes place, the landscape may progress through different stages and continuously transform in appearance. On gradually sloped terrain, desertification can create increasingly larger empty spaces over a large strip of land, a phenomenon known as "brousse tigrée". A mathematical model of this phenomenon proposed by C. Klausmeier attributes this patterning to dynamics in plant-water interaction.[39] One outcome of this observation suggests an optimal planting strategy for agriculture in arid environments.[40]

Causes
Preventing man-made overgrazing
Goats inside of a pen in Norte Chico, Chile. Overgrazing of drylands by poorly managed traditional herding is one of the primary causes of desertification.
Wildebeest in Masai Mara during the Great Migration. Overgrazing is not necessarily caused by nomadic grazers in large travelling herd populations.[41][42]

The immediate cause is the loss of most vegetation. This is driven by a number of factors, alone or in combination, such as drought, climatic shifts, tillage for agriculture, overgrazing and deforestation for fuel or construction materials. Vegetation plays a major role in determining the biological composition of the soil. Studies have shown that, in many environments, the rate of erosion and runoff decreases exponentially with increased vegetation cover.[43] Unprotected, dry soil surfaces blow away with the wind or are washed away by flash floods, leaving infertile lower soil layers that bake in the sun and become an unproductive hardpan.

Many scientists think that one of the most common causes is overgrazing, too much consumption of vegetation by cattle or other livestock.

A shepherd guiding his sheep through the high desert outside Marrakech, Morocco

Scientists agree that the existence of a desert in the place where the Sahara desert is now located is due to a natural climate cycle; this cycle often causes a lack of water in the area from time to time. There is a suggestion that the last time that the Sahara was converted from savanna to desert it was partially due to overgrazing by the cattle of the local population.[44]

Researchers from Hacettepe University have reported that Saharan soil may have bio-available iron and also some essential macro and micro nutrient elements suitable for use as fertilizer for growing wheat. It has been shown that Saharan soil may have the potential of producing bioavailable iron when illuminated with visible light and also it has some essential macro and micro nutrient elements. In this study the impact of various growth media on development of some bread wheat (Triticum aestivum L.) and durum wheat (Triticum durum L.) cultivars have been investigated. As a four different nutrient media, Hewitt nutrient solution [1], illuminated and non-illuminated Saharan desert soil solutions and distilled water have been utilized. Shoot length (cm.seedling-1), leaf area (cm2 seedling-1) and photosynthetic pigments [chlorophyll a, chlorophyll b and carotenoids, mg ml-1 g fresh weight (g fw)-1] have been determined. The results of this study indicate that, wheat varieties fed by irradiated Saharan soil solution gave comparable results to Hewitt nutrient solution.[45]

Overpopulation is one of the most dangerous factors contributing to desertification. Human populations are increasing at exponential rates, which leads to overgrazing, over-farming and deforestation, as previously acceptable techniques are becoming less sustainable.[46]

Climate change is likely a major contributing factor in the desertification process, as simulations suggest the greenhouse effect may increase the spread of deserts by as much as 20%.[3]

There are multiple reasons farmers use intensive farming as opposed to extensive farming but the main reason is to maximize yields.[37] By increasing productivity, they require a lot more fertilizer, pesticides, and labor to upkeep machinery. This continuous use of the land rapidly depletes the nutrients of the soil causing desertification to spread.[47][48]

Poverty

At least 90% of the inhabitants of drylands live in developing countries, where they also suffer from poor economic and social conditions.[18] This situation is exacerbated by land degradation because of the reduction in productivity, the precariousness of living conditions and the difficulty of access to resources and opportunities.[49]

A downward spiral is created in many underdeveloped countries by overgrazing, land exhaustion and overdrafting of groundwater in many of the marginally productive world regions due to overpopulation pressures to exploit marginal drylands for farming. Decision-makers are understandably averse to invest in arid zones with low potential. This absence of investment contributes to the marginalisation of these zones. When unfavourable agro-climatic conditions are combined with an absence of infrastructure and access to markets, as well as poorly adapted production techniques and an underfed and undereducated population, most such zones are excluded from development.[50]

Desertification often causes rural lands to become unable to support the same sized populations that previously lived there. This results in mass migrations out of rural areas and into urban areas (urbanisation), particularly in Africa. These migrations into the cities often cause large numbers of unemployed people, who end up living in slums.[51][52]

In Mongolia the land is 90% fragile dry land, which causes many herders to migrate to the city for work. With very limited resources the herders that stay in the dry land graze very carefully in order to preserve the land. With the increasing population of Mongolia it is very difficult to stay a herder for long.[53]

The number of these environmental refugees grows every year, with projections for sub-Saharan Africa showing a probable increase from 14 million in 2010 to nearly 200 million by 2050. This presents a future crisis for the region, as neighboring nations do not always have the ability to support large populations of refugees.[54][55]

Agriculture is a main source of income for many desert communities. The increase in desertification in these regions has degraded the land to such an extent where people can no longer productively farm and make a profit. This has negatively impacted the economy and increased poverty rates.[56]

Countermeasures
Anti-sand shields in north Sahara, Tunisia
Jojoba plantations, such as those shown, have played a role in combating edge effects of desertification in the Thar Desert, India.[57]

Techniques and countermeasures exist for mitigating or reversing the effects of desertification, and some possess varying levels of difficulty. For some, there are numerous barriers to their implementation. Yet for others, the solution simply requires the exercise of human reason.

One proposed barrier is that the costs of adopting sustainable agricultural practices sometimes exceed the benefits for individual farmers, even while they are socially and environmentally beneficial.[58] Another issue is a lack of political will, and lack of funding to support land reclamation and anti-desertification programs.[59]

Desertification is recognized as a major threat to biodiversity. Some countries have developed biodiversity action plans to counter its effects, particularly in relation to the protection of endangered flora and fauna.[60][61]

Reforestation gets at one of the root causes of desertification and is not just a treatment of the symptoms. Environmental organizations[62] work in places where deforestation and desertification are contributing to extreme poverty. There they focus primarily on educating the local population about the dangers of deforestation and sometimes employ them to grow seedlings, which they transfer to severely deforested areas during the rainy season.[63] The Food and Agriculture Organization of the United Nations launched the FAO Drylands Restoration Initiative in 2012 to draw together knowledge and experience on dryland restoration.[64] In 2015, FAO published global guidelines for the restoration of degraded forests and landscapes in drylands, in collaboration with the Turkish Ministry of Forestry and Water Affairs and the Turkish Cooperation and Coordination Agency.[65]

The "Green Wall of China" is a high-profile example of one method that has been finding success in this battle with desertification.. This wall is a much larger-scale version of what American farmers did in the 1930s to stop the great Midwest dust bowl. This plan was proposed in the late 1970s, and has become a major ecological engineering project that is not predicted to end until the year 2055. According to Chinese reports, there have been nearly 66 billion trees planted in China's great green wall.[66] The green wall of China has decreased desert land in China by an annual average of 1,980 square km.[67] The frequency of sandstorms nationwide have fallen 20% due to the green wall.[68] Due to the success that China has been finding in stopping the spread of desertification, plans are currently be made in Africa to start a "wall" along the borders of the Sahara desert as well to be financed by the United Nations Global Environment Facility trust.[69]

in 2007 the African Union started the great green wall of Africa project in order to combat desertification in 20 countries. the wall is 8000 km wide stretching across the entire width of the continent and has 8 billion dollars in support of the project. The great green wall of Africa has restored 36 million hectares of land to the countries and has created many job opportunities for those who dwell near it.[70] The great green wall has created over 20,000 jobs in Nigeria alone.[71]

Techniques focus on two aspects: provisioning of water, and fixation and hyper-fertilizing soil. Fixating the soil is often done through the use of shelter belts, woodlots and windbreaks. Windbreaks are made from trees and bushes and are used to reduce soil erosion and evapotranspiration. They were widely encouraged by development agencies from the middle of the 1980s in the Sahel area of Africa.

Some soils (for example, clay), due to lack of water can become consolidated rather than porous (as in the case of sandy soils). Some techniques as zaï or tillage are then used to still allow the planting of crops.[72] Waffle gardens can also help as they can provide protection of the plants against wind/sandblasting, and increase the hours of shade falling on the plant.[73]

Another technique that is useful is contour trenching. This involves the digging of 150 m long, 1 m deep trenches in the soil. The trenches are made parallel to the height lines of the landscape, preventing the water from flowing within the trenches and causing erosion. Stone walls are placed around the trenches to prevent the trenches from closing up again. The method was invented by Peter Westerveld.[74]

Enriching of the soil and restoration of its fertility is often achieved by plants. Of these, leguminous plants which extract nitrogen from the air and fix it in the soil, succulents (such as Opuntia),[75] and food crops/trees as grains, barley, beans and dates are the most important. Sand fences can also be used to control drifting of soil and sand erosion.[76]

Another way to restore soil fertility is through the use of nitrogen-rich fertilizer. Due to the higher cost of this fertilizer, many smallholder farmers are reluctant to use it, especially in areas where subsistence farming is common.[77] Several nations, including India, Zambia, and Malawi have responded to this by implementing subsidies to help encourage adoption of this technique.[78]

Some research centres (such as Bel-Air Research Center IRD/ISRA/UCAD) are also experimenting with the inoculation of tree species with mycorrhiza in arid zones. The mycorrhiza are basically fungi attaching themselves to the roots of the plants. They hereby create a symbiotic relation with the trees, increasing the surface area of the tree's roots greatly (allowing the tree to gather much more nutrient from the soil).[79]

As there are many different types of deserts, there are also different types of desert reclamation methodologies. An example for this is the salt flats in the Rub' al Khali desert in Saudi Arabia. These salt flats are one of the most promising desert areas for seawater agriculture and could be revitalized without the use of freshwater or much energy.[80]

Farmer-managed natural regeneration (FMNR) is another technique that has produced successful results for desert reclamation. Since 1980, this method to reforest degraded landscape has been applied with some success in Niger. This simple and low-cost method has enabled farmers to regenerate some 30,000 square kilometers in Niger. The process involves enabling native sprouting tree growth through selective pruning of shrub shoots. The residue from pruned trees can be used to provide mulching for fields thus increasing soil water retention and reducing evaporation. Additionally, properly spaced and pruned trees can increase crop yields. The Humbo Assisted Regeneration Project which uses FMNR techniques in Ethiopia has received money from The World Bank's BioCarbon Fund, which supports projects that sequester or conserve carbon in forests or agricultural ecosystems.[81]

Managed grazing

Restoring grasslands store CO2 from the air as plant material. Grazing livestock, usually not left to wander, eat the grass and minimize grass growth.[82] A method proposed to restore grasslands uses fences with many small paddocks and moving herds from one paddock to another after a day or two in order to mimic natural grazers and allowing the grass to grow optimally.[82][83][84] Proponents of managed grazing methods estimate that increasing this method could increase carbon content of the soils in the world's 3.5 billion hectares of agricultural grassland and offset nearly 12 years of CO2 emissions.[82]

One proponent of managed grazing, Allan Savory, as part of holistic management, claims that keeping livestock tightly packed on smaller plots of land, meanwhile rotating them to other small plots of land will reverse desertification;[85] range scientists have however not been able to experimentally confirm his claims.[86][87][88][89][90][91][92]

gollark: So I was thinking of an AutoBotRobot "virtual channel" publish/subscribe bridge where Discord channels could link up to a virtual channel, and IRC could also link to that via some glue code, and all would be cool and good™, and ApioTelephone could just create virtual channels temporarily.
gollark: I want to unify these in a nice elegant™ way.
gollark: So, I run something like two different bridgey things on my server now - APIONET to various Discord channels (this was bodged into inter-discord-channel links also) and ABR's apiotelephone thing.
gollark: I have a somewhat technical architecture question and as is convention I will now be polling you for answers.
gollark: I have a bizarre ability to *sometimes* do mundane repetitive tasks. Right now I'm adding bots to heavserver in vast quantities.

See also
Wind erosion outside Leuchars

Mitigation:

Other related portals:

References
  1. Onamuti, Olapeju Y.; Okogbue, Emmanuel C.; Orimoloye, Israel R. (8 November 2017). "Remote sensing appraisal of Lake Chad shrinkage connotes severe impacts on green economics and socio-economics of the catchment area". Royal Society Open Science. 4 (11): 171120. doi:10.1098/rsos.171120. PMC 5717671. PMID 29291097.
  2. Rafferty, John P.; Pimm, Stuart L. (2019). "Desertification.". Encyclopædia Britannica. Retrieved 2019-11-06. the process by which natural or human causes reduce the biological productivity of drylands (arid and semiarid lands). ... The concept does not refer to the physical expansion of existing deserts but rather to the various processes that threaten all dryland ecosystems.
  3. Zeng, Ning; Yoon, Jinho (1 September 2009). "Expansion of the world's deserts due to vegetation-albedo feedback under global warming". Geophysical Research Letters. 36 (17): L17401. Bibcode:2009GeoRL..3617401Z. doi:10.1029/2009GL039699. ISSN 1944-8007.
  4. "Sustainable development of drylands and combating desertification". Retrieved 21 June 2016.
  5. "The Desert Will Win". FIGU-Landesgruppe Canada. Archived from the original on 2017-01-02. Retrieved 2017-01-02.
  6. Geist (2005), p. 4
  7. Geist (2005), p. 2
  8. Rafferty, John P.; Pimm, Stuart L. (2019). "Desertification". Encyclopædia Britannica. Retrieved 2019-11-06. The concept does not refer to the physical expansion of existing deserts but rather to the various processes that threaten all dryland ecosystems.
  9. "Part I". Archived from the original on 7 June 2016. Retrieved 21 June 2016.
  10. Helmut J. Geist, and Eric F. Lambin. "Dynamic Causal Patterns of Desertification." BioScience 54.9 (2004): 817 . Web.
  11. United States Geological Survey, "Desertification", 1997
  12. LOWDERMILK, W C. "CONQUEST OF THE LAND THROUGH SEVEN THOUSAND YEARS" (PDF). Soil Conservation Service. United States Department of Agriculture. Retrieved 9 April 2014.
  13. Dregne, H.E. "Desertification of Arid Lands". Columbia University. Retrieved 3 December 2013.
  14. Mortimore, Michael (1989). Adapting to drought: farmers, famines, and desertification in West Africa. Cambridge University Press. p. 12. ISBN 978-0-521-32312-3.
  15. "Sun, Moon and Telescopes above the Desert". ESO Picture of the Week. Retrieved 30 April 2012.
  16. Bauer (2007), p. 78
  17. Johnson et al (2006), p. 1
  18. "UNCCD: Impact and role of drylands". UNCCD. 10 October 2017. Retrieved 7 November 2019.
  19. World Bank (2009). Gender in agriculture sourcebook. World Bank Publications. p. 454. ISBN 978-0-8213-7587-7.
  20. "IRI – International Research Institute for Climate and Society" (PDF).
  21. Riebeek, Holli (2007-01-03). "Defining Desertification : Feature Articles". earthobservatory.nasa.gov. Retrieved 2016-11-30.
  22. Christian Bouquet (December 2017). "Le Sahara entre ses deux rives. Éléments de délimitation par la géohistoire d'un espace de contraintes". Géoconfluences. Mais il aurait progressé de 250 km vers le sud depuis 1900 (Mainguet, 2003), et dépasserait donc 9 millions de km² soit 30 % de la superficie totale du continent africain.
  23. Mainguet, Monique (2003). Les pays secs: environnement et développement. Ellipses.
  24. "United Nations Convention to Combat Desertification: Issues and Challenges". E-International Relations. Retrieved 2016-11-30.
  25. Dougill, Andrew (November 2016). "Lake drying and livelihood dynamics in Lake Chad: Unravelling the mechanisms, contexts and responses". Ambio. 45 (7): 781–795. doi:10.1007/s13280-016-0805-6. PMC 5055484. PMID 27371137.
  26. Mohamed, Dounia Ben (December 2015). "New Urgency in Battle to Halt Spread of Desertification". New African. 556 – via Gale Academic OneFile Select.
  27. "Croatia Population (2020) - Worldometer". www.worldometers.info. Retrieved 2020-01-16.
  28. "Living in China's Expanding Deserts". The New York Times. 2016-10-24.
  29. http://www.geo.utexas.edu/courses/371c/project/2009/Welker_Desertification.pdf
  30. Torres, Laura; Abraham, Elena M.; Rubio, Clara; Barbero‐Sierra, Celia; Ruiz-Pérez, Manuel (7 July 2015). "Desertification Research in Argentina". Land Degradation & Development. 26 (5): 433–440. doi:10.1002/ldr.2392.
  31. Mongolia : state of the environment, 2002 (PDF). United Nations Environment Programme. Pathumthani, Thailand: United Nations Environment Programme. 2001. ISBN 92-807-2145-3. OCLC 63522565.CS1 maint: others (link)
  32. "Report on the State of the Environment of Mongolia, 2008-2010" (PDF). Ministry of Nature Environment and Tourism. Retrieved 2020-06-17. Cite journal requires |journal= (help)
  33. Dorj, O.; Enkhbold, M.; Lkhamyanjin, S.; Mijiddorj, Kh.; Nosmoo, A.; Puntsagnamil, M.; Sainjargal, U. (2013), Heshmati, G. Ali; Squires, Victor R. (eds.), "Mongolia: Country Features, the Main Causes of Desertification and Remediation Efforts", Combating Desertification in Asia, Africa and the Middle East, Dordrecht: Springer Netherlands, pp. 217–229, doi:10.1007/978-94-007-6652-5_11, ISBN 978-94-007-6651-8, retrieved 2020-06-17
  34. Stanelle, Tanja; Bey, Isabelle; Raddatz, Thomas; Reick, Christian; Tegen, Ina (2014-12-16). "Anthropogenically induced changes in twentieth century mineral dust burden and the associated impact on radiative forcing". Journal of Geophysical Research: Atmospheres. 119 (23): 13, 526–13, 546. Bibcode:2014JGRD..11913526S. doi:10.1002/2014JD022062. hdl:11858/00-001M-0000-0024-A9A2-C.
  35. Namdari, Soodabeh; Karimi, Neamat; Sorooshian, Armin; Mohammadi, GholamHasan; Sehatkashani, Saviz (2018-01-01). "Impacts of climate and synoptic fluctuations on dust storm activity over the Middle East". Atmospheric Environment. 173: 265–276. Bibcode:2018AtmEn.173..265N. doi:10.1016/j.atmosenv.2017.11.016. ISSN 1352-2310. PMC 6192056. PMID 30344444.
  36. Goudie, Andrew S. (2014-02-01). "Desert dust and human health disorders". Environment International. 63: 101–113. doi:10.1016/j.envint.2013.10.011. ISSN 0160-4120. PMID 24275707.
  37. "Explainer: Desertification and the role of climate change". Carbon Brief. 2019-08-06. Retrieved 2019-10-22.
  38. "WAD | World Atlas of Desertification". wad.jrc.ec.europa.eu. Retrieved 2019-11-19.
  39. Klausmeier, Christopher (1999). "Regular and irregular patterns in semiarid vegetation". Science. 284 (5421): 1826–1828. doi:10.1126/science.284.5421.1826. PMID 10364553.
  40. (www.dw.com), Deutsche Welle. "Grid of straw squares turns Chinese sand to soil – Environment – DW.COM – 23.06.2011". Retrieved 21 June 2016.
  41. Laduke, Winona (1999). All Our Relations: Native Struggles for Land and Life. Cambridge, MA: South End Press. p. 146. ISBN 978-0896085992. Retrieved 30 March 2015.
  42. Duval, Clay. "Bison Conservation: Saving an Ecologically and Culturally Keystone Species" (PDF). Duke University. Archived from the original (PDF) on March 8, 2012. Retrieved April 13, 2015.
  43. Geeson, Nichola; et al. (2002). Mediterranean desertification: a mosaic of processes and responses. John Wiley & Sons. p. 58. ISBN 978-0-470-84448-9.
  44. K. Wright, David; Rull, Valenti; Roberts, Richard; Marchant, Rob; Gil-Romera, Graciela (26 January 2017). "Humans as Agents in the Termination of the African Humid Period". Frontiers in Earth Science. 5: 4. Bibcode:2017FrEaS...5....4W. doi:10.3389/feart.2017.00004.
  45. Yücekutlu, Nihal; Terzioğlu, Serpil; Saydam, Cemal; Bildacı, Işık (2011)."Organic Farming By Using Saharan Soil: Could It Be An Alternative To Fertilizers?" Hacettepe Journal of Biology and Chemistry. 39 (1): 29–38.
  46. Epule, Terence Epule; Peng, Changhui; Lepage, Laurent (February 2015). "Environmental refugees in sub-Saharan Africa: a review of perspectives on the trends, causes, challenges and way forward". GeoJournal. 80 (1): 79–92. doi:10.1007/s10708-014-9528-z. ISSN 0343-2521.
  47. "World Day to Combat Desertification and Drought, 17 June". www.un.org. Retrieved 2019-11-19.
  48. "Intensive agriculture". Encyclopedia Britannica. Retrieved 2019-11-19.
  49. Dobie, Ph. 2001. “Poverty and the drylands”, in Global Drylands Imperative, Challenge paper, Undp, Nairobi (Kenya) 16 p.
  50. Cornet A., 2002. Desertification and its relationship to the environment and development: a problem that affects us all. In: Ministère des Affaires étrangères/adpf, Johannesburg. World Summit on Sustainable Development. 2002. What is at stake? The contribution of scientists to the debate: 91–125.. Archived 2009-08-09 at the Wayback Machine
  51. Pasternak, Dov; Schlissel, Arnold (2001). Combating desertification with plants. Springer. p. 20. ISBN 978-0-306-46632-8.
  52. Briassoulis, Helen (2005). Policy integration for complex environmental problems: the example of Mediterranean desertification. Ashgate Publishing. p. 161. ISBN 978-0-7546-4243-5.
  53. Gillet, Kit (April 2011). "A way of life in crisis: on the sparsely inhabited steppes of Mongolia, the lifestyle of the nomadic herder has always been a hard one. But as livestock die in their millions during the increasingly frequent bitter winters, and pasturelands disappear due to overgrazing and desertification, this traditional culture is struggling to survive". Circle Publishing Ltd.
  54. Myers, Norman (29 April 2002). "Environmental refugees: a growing phenomenon of the 21st century". Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences. 357 (1420): 609–613. doi:10.1098/rstb.2001.0953. PMC 1692964. PMID 12028796.
  55. Epule, Terence Epule; Peng, Changhui; Lepage, Laurent (5 February 2014). "Environmental refugees in sub-Saharan Africa: a review of perspectives on the trends, causes, challenges and way forward". GeoJournal. 80: 79–92. doi:10.1007/s10708-014-9528-z.
  56. Stringer, Lindsay C.; Dyer, Jen C.; Reed, Mark S.; Dougill, Andrew J.; Twyman, Chasca; Mkwambisi, David (2009). "Adaptations to climate change, drought and desertification: local insights to enhance policy in southern Africa". Environmental Science & Policy. 12 (7): 748–765. doi:10.1016/j.envsci.2009.04.002.
  57. Pasternak, D.; Schlissel, Arnold (2012-12-06). Combating Desertification with Plants. Springer Science & Business Media. p. 38. ISBN 9781461513278.
  58. Drost, Daniel; Long, Gilbert; Wilson, David; Miller, Bruce; Campbell, William (1 December 1996). "Barriers to Adopting Sustainable Agricultural Practices". Journal of Extension. 34 (6).
  59. Briassoulis, Helen (2005). Policy integration for complex environmental problems: the example of Mediterranean desertification. Ashgate Publishing. p. 237. ISBN 978-0-7546-4243-5.
  60. Techniques for Desert Reclamation by Andrew S. Goudie
  61. Desert reclamation projects Archived 2009-01-03 at the Wayback Machine
  62. For example, Eden Reforestation Projects website, on Vimeo, on Eden Reforestation Projects on YouTube.
  63.  This article incorporates public domain material from the United States Government document: "http://pubs.usgs.gov/gip/deserts/desertification/".
  64. "Drylands Restoration Initiative". Food and Agriculture Organization of the United Nations. Retrieved 14 April 2016.
  65. Global guidelines for the restoration of degraded forests and landscapes in drylands (PDF). Food and Agriculture Organization of the United Nations. June 2015. ISBN 978-92-5-108912-5.
  66. "China's 'Great Green Wall' Fights Expanding Desert". 2017-04-21.
  67. Hui, Lu (May 26, 2018). "Across China: A guardian of the great green wall against China's second largest desert". Xinghua News Agency.
  68. Beiser, Vince (September 1, 2017). "A tree grows in China: can a "Green Great Wall" stop sand from devouring the countryside?". Mother Jones. 83 (4).
  69. Gadzama, Njidda Mamadu (2017). "Attenuation of the effects of desertification through sustainable development of Great Green Wall in the Sahel of Africa". World Journal of Science, Technology and Sustainable Development. 14 (4): 279–289. doi:10.1108/WJSTSD-02-2016-0021.
  70. Gadzama, Njidda (2017). "Attenuation of the Effects of Desertification through Sustainable Development of Great Green Wall in the Sahel of Africa". World Journal of Science, Technology and Sustainable Development. 14 (4): 279–289. doi:10.1108/WJSTSD-02-2016-0021.
  71. United Nations Convention to Combat Desertification (2019). "The Great Green Wall Initiative". uncdd.int. Retrieved 12/3/19. Check date values in: |access-date= (help)
  72. "Our Good Earth – National Geographic Magazine". Retrieved 21 June 2016.
  73. Grow Vegetables in the Desert With a 'Waffle Garden'
  74. "Home – Justdiggit". Archived from the original on 2 April 2016. Retrieved 21 June 2016.
  75. Cactus as a tool to mitigate drought and to combat Desertification
  76. List of plants to halt desertification; some of which may be soil-fixating Archived 2011-02-01 at the Wayback Machine
  77. Krah, Kwabena; Michelson, Hope; Perge, Emilie; Jindal, Rohit (1 December 2019). "Constraints to adopting soil fertility management practices in Malawi: A choice experiment approach". World Development. 124: 104651. doi:10.1016/j.worlddev.2019.104651.
  78. Duflo, Esther; Kremer, Michael; Robinson, Jonathan (October 2011). "Nudging Farmers to Use Fertilizer: Theory and Experimental Evidence from Kenya" (PDF). American Economic Review. 101 (6): 2350–2390. doi:10.1257/aer.101.6.2350.
  79. "Département Biologie Végétale – Laboratoire Commun de Microbiologie IRD-ISRA-UCAD". Retrieved 21 June 2016.
  80. Rethinking landscapes, Nicol-André Berdellé July 2011 H2O magazine
  81. "Sprouting Trees From the Underground Forest — A Simple Way to Fight Desertification and Climate Change – Water Matters – State of the Planet". Blogs.ei.columbia.edu. 2011-10-18. Retrieved 2012-08-11.
  82. "How fences could save the planet". newstatesman.com. January 13, 2011. Retrieved May 5, 2013.
  83. "Restoring soil carbon can reverse global warming, desertification and biodiversity". mongabay.com. February 21, 2008. Archived from the original on June 25, 2013. Retrieved May 5, 2013.
  84. Abend, Lisa (January 25, 2010). "How eating grass-fed beef could help fight climate change". time.com. Retrieved May 11, 2013.
  85. "How cows could repair the world". nationalgeographic.com. March 6, 2013. Retrieved May 5, 2013.
  86. Briske, D. D. "Origin, Persistence, and Resolution of the Rotational Grazing Debate: Integrating Human Dimensions Into Rangeland Research" (PDF). Rangeland Ecol Manage 64:325–334. Retrieved 6 April 2013.
  87. D. D. Briske, J. D. Derner, J. R. Brown, S. D. Fuhlendorf, W. R. Teague, K. M. Havstad, R. L. Gillen, A. J. Ash, W. D. Willms, (2008) Rotational Grazing on Rangelands: Reconciliation of Perception and Experimental Evidence. Rangeland Ecology & Management: January 2008, Vol. 61, No. 1, pp. 3-17.
  88. Savory, Allan. "Allan Savory: How to green the world's deserts and reverse climate change".
  89. Savory, Allan. "Holistic resource management: a conceptual framework for ecologically sound economic modelling" (PDF). Ecological Economics. Elsevier Science Publishers. Archived from the original (PDF) on 23 May 2013. Retrieved 10 March 2013.
  90. Butterfield, Jody (2006). Holistic Management Handbook: Healthy Land, Healthy Profits, Second Edition. Island Press. ISBN 978-1559638852.
  91. Savory, Allan. "Response to request for information on the "science" and "methodology" underpinning Holistic Management and holistic planned grazing" (PDF). Savory Institute. Archived from the original (PDF) on 23 May 2013. Retrieved 10 March 2013.
  92. Drury, Steve (2012-04-13). "Large-animal extinction in Australia linked to human hunters". Earth-Pages. Retrieved 9 June 2014.

Bibliography
  • Arnalds, Ólafur; Archer, Steve (2000). Rangeland Desertification. Springer. ISBN 978-0-7923-6071-1.
  • Barbault R., Cornet A., Jouzel J., Mégie G., Sachs I., Weber J. (2002). Johannesburg. World Summit on Sustainable Development. 2002. What is at stake? The contribution of scientists to the debate. Ministère des Affaires étrangères/adpf.
  • Bauer, Steffan (2007). "Desertification". In Thai, Khi V.; et al. (eds.). Handbook of globalization and the environment. CRC Press. ISBN 978-1-57444-553-4.
  • Batterbury, S.P.J. & A.Warren (2001) Desertification. in N. Smelser & P. Baltes (eds.) International Encyclopædia of the Social and Behavioral Sciences. Elsevier Press. pp. 3526–3529
  • D’Odorico P., A. Bhattachan, K.F. Davis, S. Ravi, C.W. Runyan, (2013). Global desertification: Drivers and feedbacks, Adv. Water Res., 51, 326–344.
  • Geist, Helmut (2005). The causes and progression of desertification. Ashgate Publishing. ISBN 978-0-7546-4323-4.
  • Hartman, Ingrid (2008). "Desertification". In Philander, S. George (ed.). Encyclopedia of global warming and climate change, Volume 1. SAGE. ISBN 978-1-4129-5878-3.
  • Hinman, C. Wiley; Hinman, Jack W. (1992). The plight and promise of arid land agriculture. Columbia University Press. ISBN 978-0-231-06612-9.
  • Holtz, Uwe (2007). Implementing the United Nations Convention to Combat Desertification from a parliamentary point of view – Critical assessment and challenges ahead. Online at
  • Holtz, Uwe (2013). Role of parliamentarians in the implementation process of the UN Convention to Combat Desertification. A guide to Parliamentary Action, ed. Secretariat of the UNCCD, Bonn ISBN 978-92-95043-69-5. Online at
  • Johnson, Pierre Marc; et al., eds. (2006). Governing global desertification: linking environmental degradation, poverty and participation. Ashgate Publishing. ISBN 978-0-7546-4359-3.
  • Lucke, Bernhard (2007): Demise of the Decapolis. Past and Present Desertification in the Context of Soil Development, Land Use, and Climate. Online at
  • Mensah, Joseph (2006). "Desertification". In Leonard, Thomas M. (ed.). Encyclopedia of the developing world, Volume 1. Taylor & Francis. ISBN 978-0-415-97662-6.
  • Millennium Ecosystem Assessment (2005) Desertification Synthesis Report
  • Moseley, W.G. and E. Jerme 2010. “Desertification.” In: Warf, B. (ed). Encyclopedia of Geography. Sage Publications. Volume 2, pp. 715–719.
  • Oliver, John E., ed. (2005). "Desertification". Encyclopedia of world climatology. Springer. ISBN 978-1-4020-3264-6.
  • Parrillo, Vincent N., ed. (2008). "Desertification". Encyclopedia of social problems, Volume 2. SAGE. ISBN 978-1-4129-4165-5.
  • Reynolds, James F., and D. Mark Stafford Smith (ed.) (2002) Global Desertification – Do Humans Cause Deserts? Dahlem Workshop Report 88, Berlin: Dahlem University Press
  • Stelt, Sjors van der (2012) Rise and Fall of Periodic Patterns for a Generalized Klausmeier-Gray-Scott Model, PhD Thesis University of Amsterdam
  • UNCCD (1994) United Nations Convention to Combat Desertification
  • The End of Eden a 90-minute documentary by South African filmmaker Rick Lomba in 1984 on African desertification
Attribution
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.