Desertification
| Subclass of | land degradation  |
|---|---|
| Facet give | developing country |
| Has cause | drylands, famine, over exploitation, effects of climate change |
| Has effect | desert, dust storm, poverty, erg |
| Relates to sustainable development goal, target or indicator | Target 15.3 of the Sustainable Development Goals |
| Handled, mitigated, or managed by | sustainable agriculture, reforestation, Soil regeneration, desert greening, afforestation |
.jpg)
Desertification be a type of gradual land degradation of fertile land into arid desert due to a combination of natural processes den human activities.
De immediate cause of desertification be de loss of chaw vegetation. Dis dey cam by a number of factors, alone anaa insyd combination, such as drought, climatic shifts, tillage for agriculture, overgrazing den deforestation for fuel anaa construction materials. Though vegetation dey play a major role insyd determining de biological composition of de soil, studies show say, insyd chaw environments, de rate of erosion den runoff decreases exponentially plus increased vegetation cover.[2] Unprotected, dry soil surfaces blow away plus de wind anaa dem be washed away by flash floods, wey dey leave infertile lower soil layers dat bake insyd de sun den cam be an unproductive hardpan.[3][4]
At least 90% of de inhabitants of dry lands live insyd developing countries, wey dem sanso suffer from poor economic den social conditions.[5] Dis situation be exacerbated by land degradation secof de reduction insyd productivity, de precariousness of living conditions den de difficulty of access to resources den opportunities.
Geographic areas wey get affected chaw dey locate insyd Africa (Sahel region), Asia (Gobi Desert den Mongolia) den parts of South America. Drylands occupy approximately 40–41% of Earth ein land area wey be home to more dan 2billion people.[6] Effects of desertification dey include sand den dust storms, food insecurity den poverty.
Methods of mitigating anaa reversing desertification dey include improving soil quality, greening deserts, managing grazing, den tree-planting (reforestation den afforestation).
Throughout geological history, de development of deserts dey occur naturally over long intervals of time.[7] De modern study of desertification emerge from de study of de 1980s drought insyd de Sahel.[8]
Definitions
[edit | edit source]Desertification be a gradual process of increased soil aridity. Desertification has been defined insyd de text of de United Nations Convention to Combat Desertification (UNCCD) as "land degradation insyd arid, semi-arid den dry sub-humid regions wey dey result from various factors, wey dey include climatic variations den human activities."[9]
Definition of Desert – dat area of de earth wey de sum of rain den snowfall be much less than oda areas, where de annual average rainfall be less than 25CM. Definition by UNO (1995) – Land degradation insyd barren, humid den sub-humid areas secof climate change den human activities dem call desertification.
As of 2005, na considerable controversy exist over de proper definition of de term desertification plus more dan 100 formal definitions insyd existence.[10] De most widely accepted of dese be dat of de Princeton University Dictionary wich define am as "de process of fertile land wey dey transform into desert typically as a result of deforestation, drought anaa improper/inappropriate agriculture". Dis definition clearly demonstrated de interconnectedness of desertification den human activities, insyd particular land use den land management practices. E sanso highlight de economic, social den environmental implications of desertification. However, dis original understanding dat desertification involved de physical expansion of deserts has been rejected as de concept has further evolved since then.[11]
Der sanso exist controversy around de sub-grouping of types of desertification, wey dey include, for example, de validity den usefulness of such terms as "man-made desert" den "non-pattern desert".[12]
Causes
[edit | edit source]Immediate causes
[edit | edit source]De immediate cause of desertification be de loss of chaw vegetation. Dis be driven by a number of factors, alone anaa insyd combination, such as drought, climatic shifts, tillage for agriculture, overgrazing den deforestation for fuel anaa construction materials. Though vegetation plays a major role insyd determining de biological composition of soil, studies dey show dat, insyd many environments, de rate of erosion den runoff decreases exponentially plus increased vegetation cover.[2] Unprotected, dry soil surfaces blow away plus de wind anaa dey wash away by flash floods, leaving infertile lower soil layers dat bake insyd de sun den becam an unproductive hardpan.
Influence of human activities
[edit | edit source]Early studies dey argue say one of de most common causes of desertification be overgrazing, over consumption of vegetation by cattle anaa oda livestock.[13] However, de role of local overexploitation insyd driving desertification insyd de recent past be controversial.[8] Drought insyd de Sahel region be now thought to be principally de result of seasonal variability insyd rainfall wey cause by large-scale sea surface temperature variations, largely driven by natural variability den anthropogenic emissions of aerosols (reflective sulphate particles) den greenhouse gases.[14] As a result, changing ocean temperature den reductions insyd sulfate emissions dey cause a re-greening of de region.[14] Dis dey lead some scholars to argue dat agriculture-induced vegetation loss be a minor factor insyd desertification.[8]
Na Human population dynamics dey get a considerable impact on overgrazing, over-farming den deforestation, as previously acceptable techniques have becam unsustainable.[15]
There are multiple reasons farmers use intensive farming as opposed to extensive farming but de main reason be to maximize yields.[16] By increasing productivity, they require a lot more fertilizer, pesticides, den labor to upkeep machinery. Dis continuous use of de land rapidly depletes de nutrients of de soil causing desertification to spread.[17][18]
Natural variations
[edit | edit source]Scientists agree dat de existence of a desert insyd de place wey de Sahara desert be now dey locate be due to natural variations insyd solar insolation due to orbital procession of de Earth.[19] Such variations influence de strength of de West African Monsoon, inducing feedback insyd vegetation den dust emission dat amplify de cycle of wet den dry Sahara climate.[20] There be sanso a suggestion de transition of de Sahara from savanna to desert during de mid-Holocene be partially due to overgrazing by de cattle of de local population.[21]
Scientists have further studied critical regions, confirming dat human activities den soil health join meteorogical factors as main contributors towards desertification. Insyd de Mu Us Desert, soil health makes up 37% of desertification events while meteorological den human activities work to counteract dis phenomenon by 46% den 17%, respectively. Inner Mongolia desertification be characterize by 24% meteorological contributions den 34.7% soil benefits throughout dis environment. Shaanxi be a counterexample insyd wich meteorological factors work against desertification den soil exacerbates am, demonstrating de various influences of natural factors throughout regions.[22]
Climate change
Research for desertification be hard, den no single metric go fit define all de aspects[23].However, bunch climate change intense be expected say ego increase de current extent of drylands on de continent for de earth inside: from 38% for de late 20th century inside to 50% anaa 56% by say de century go end, under de "moderate" den high-warming Representative Concentration Pathways 4.5 den 8.5. Buncg of de expansion go be seen over regions such as "southwest North America, den northern fringe of Africa, southern Africa, den Australia".
Drylands dey cover 41% of de land surface for de earth inside wey dey include 45% of de world's agricultural land.[24] De regions dey part of de ecosystem wey be vulnerable to anthropogenic climate den land use change wey desertification be threat to. An observation-based attribution study for desertification inside was carried out for 2020 inside wey account for climate change, climate variability, CO2 fertilization as well as both de gradual den rapid ecosystem changes caused by land use.[25] De study find say, between 1982 den 2015, 6% of de drylands for de world inside go though desertification wey be driven by unsustainable land use practices compounded by anthropogenic climate change. Despite de average global greening, anthropogenic climate change degrade 12.6%12.6% (5.43 million km2) of drylands, contributing to desertification den dey affect 213 million people, 93% of people wey dey live for developing economies inside.[26]
Agriculture and farming activities
Farming activities such as overgrazing dey cause desertification[27] . For dis farming activity inside, livestock such as cattle den cows are allowed to feed for a piece of land top for a long period of time without planting grasses wey go replace dem. As a result of dis, de land becomes bare, exposed to heat from de sun which dey cause am to harden, heavy wind which also dey cause de land to loose ein nutrients.[28] Overcultivation den Monocropping den other farming activities wey dey cause desertification in Africa. Planting de same crop repeatedly on de same land dey drains essential nutrients in de land. As de soil be depleted, it dey loose de organic matter den de ability to retain moisture, causing de soil to harden den crack.[29]
References
[edit | edit source]- ↑ European Commission. Joint Research Centre. (2018). World atlas of desertification :rethinking land degradation and sustainable land management. LU: Publications Office. doi:10.2760/9205. ISBN 978-92-79-75349-7.
- 1 2 Geeson, Nichola; et al. (2002). Mediterranean desertification: a mosaic of processes and responses. John Wiley & Sons. p. 58. ISBN 978-0-470-84448-9. Archived from the original on 30 July 2023. Retrieved 16 May 2016.
- ↑ "Sustainable development of drylands and combating desertification". Archived from the original on 4 August 2017. Retrieved 21 June 2016.
- ↑ 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. S2CID 1708267.
- ↑ "2010–2020: UN Decade for Deserts and the Fight against Desertification". www.un.org (in English). Retrieved 2026-06-10.
- ↑ Global Drylands Report unemg.org 2018
- ↑ "Desertification". pubs.usgs.gov. Retrieved 2026-06-10.
- 1 2 3 Behnke, Roy; Mortimore, Michael, eds. (2016). The End of Desertification?. Springer Earth System Sciences (in English). doi:10.1007/978-3-642-16014-1. ISBN 978-3-642-16013-4. ISSN 2197-9596. S2CID 132424053.
- ↑ Hulme, Mike; Kelly, Mick (1993). "Exploring the links between Desertification and Climate Change". Environment: Science and Policy for Sustainable Development (in English). 35 (6): 4–45. Bibcode:1993ESPSD..35f...4H. doi:10.1080/00139157.1993.9929106. ISSN 0013-9157.
- ↑ Geist, Helmut (1 October 2017). The Causes and Progression of Desertification. London: Routledge. doi:10.4324/9781315240855. ISBN 978-1-315-24085-5.
- ↑ Rafferty, John P.; Pimm, Stuart L. (26 January 2023). "Desertification". Encyclopædia Britannica. Retrieved 6 November 2019.
The concept does not refer to the physical expansion of existing deserts but rather to the various processes that threaten all dryland ecosystems.
- ↑ Geist, Helmut J.; Lambin, Eric F. (2004). "Dynamic Causal Patterns of Desertification". BioScience (in English). 54 (9): 817. doi:10.1641/0006-3568(2004)054[0817:DCPOD]2.0.CO;2. ISSN 0006-3568.
- ↑ Charney, J. G. (April 1975). "Dynamics of deserts and drought in the Sahel". Quarterly Journal of the Royal Meteorological Society (in English). 101 (428): 193–202. Bibcode:1975QJRMS.101..193C. doi:10.1002/qj.49710142802. Archived from the original on 30 July 2023. Retrieved 24 May 2022.
- 1 2 Biasutti, Michela (July 2019). "Rainfall trends in the African Sahel: Characteristics, processes, and causes". WIREs Climate Change (in English). 10 (4) e591. Bibcode:2019WIRCC..10E.591B. doi:10.1002/wcc.591. ISSN 1757-7780. PMC 6617823. PMID 31341517.
- ↑ 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. Bibcode:2015GeoJo..80...79E. doi:10.1007/s10708-014-9528-z. ISSN 0343-2521. S2CID 154503204.
- ↑ "Explainer: Desertification and the role of climate change". Carbon Brief (in English). 6 August 2019. Archived from the original on 10 February 2022. Retrieved 22 October 2019.
- ↑ United Nations. "World Day to Combat Desertification and Drought". United Nations (in English). Retrieved 11 September 2023.
- ↑ "Intensive agriculture". Encyclopedia Britannica (in English). Archived from the original on 24 June 2008. Retrieved 19 November 2019.
- ↑ Tierney, Jessica E.; Pausata, Francesco S. R.; deMenocal, Peter B. (6 January 2017). "Rainfall regimes of the Green Sahara". Science Advances (in English). 3 (1) e1601503. Bibcode:2017SciA....3E1503T. doi:10.1126/sciadv.1601503. ISSN 2375-2548. PMC 5242556. PMID 28116352.
- ↑ Pausata, Francesco S. R.; Messori, Gabriele; Zhang, Qiong (15 January 2016). "Impacts of dust reduction on the northward expansion of the African monsoon during the Green Sahara period". Earth and Planetary Science Letters (in English). 434: 298–307. Bibcode:2016E&PSL.434..298P. doi:10.1016/j.epsl.2015.11.049. ISSN 0012-821X.
- ↑ 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.
- ↑ Li, Jiaying; Li, Yu; Wang, Xuhui; Ma, Zhongxu (22 October 2024). "Exploring the Spatial-Temporal Patterns, Drivers, and Response Strategies of Desertification in the Mu Us Desert from Multiple Regional Perspectives". Sustainability (in English). 16 (21): 9154. Bibcode:2024Sust...16.9154L. doi:10.3390/su16219154. ISSN 2071-1050.
- ↑ Cite error: The opening
<ref>tag is malformed or has a bad name. - ↑ Cite error: The opening
<ref>tag is malformed or has a bad name. - ↑ Burrell, A. L.; Evans, J. P.; De Kauwe, M. G. (2020-07-31). "Anthropogenic climate change has driven over 5 million km2 of drylands towards desertification". Nature Communications. 11 (1): 3853. doi:10.1038/s41467-020-17710-7. ISSN 2041-1723. PMC 7395722. PMID 32737311.
- ↑ Burrell, A. L.; Evans, J. P.; De Kauwe, M. G. (2020-07-31). "Anthropogenic climate change has driven over 5 million km2 of drylands towards desertification". Nature Communications (in English). 11 (1): 3853. doi:10.1038/s41467-020-17710-7. ISSN 2041-1723. PMC 7395722. PMID 32737311.
- ↑ Otterman, Joseph (1974-11-08). "Baring High-Albedo Soils by Overgrazing: A Hypothesized Desertification Mechanism". Science. 186 (4163): 531–533. doi:10.1126/science.186.4163.531.
- ↑ "Desertification", Wikipedia (in English), 2026-06-23, retrieved 2026-06-23
- ↑ "Desertification, its Causes and why it Matters", Desertification, Land Degradation and Sustainability (in English), John Wiley & Sons, Ltd, pp. 3–39, 2011, doi:10.1002/9781119977759.ch1, ISBN 978-1-119-97775-9, retrieved 2026-06-23
External links
[edit | edit source]
- Official website of the Secretariat of the United Nations Convention to Combat Desertification (UNCCD)
- Procedural history and related documents on the UNCCD, from the United Nations Audiovisual Library of International Law
- Official website of Action Against Desertification, a United Nations Food and Agriculture Organization initiative of the African, Caribbean and Pacific Group of States
- Global Deserts Outlook (2006), thematic assessment report in the Global Environment Outlook (GEO) series of the United Nations Environment Program (UNEP).
