Land degradation

(Redirected from Soil exhaustion)

Land degradation is a process where land becomes less healthy and productive due to a combination of human activities or natural conditions. The causes for land degradation are numerous and complex.[1] Human activities are often the main cause, such as unsustainable land management practices. Natural hazards are excluded as a cause; however human activities can indirectly affect phenomena such as floods and wildfires.

Overgrazing by livestock can lead to land degradation.

One of the impacts of land degradation is that it can diminish the natural capacity of the land to store and filter water leading to water scarcity. Human-induced land degradation and water scarcity are increasing the levels of risk for agricultural production and ecosystem services.[1]

The United Nations estimate that about 30% of land is degraded worldwide, and about 3.2 billion people reside in these degrading areas, giving a high rate of environmental pollution.[2] Land degradation reduces agricultural productivity, leads to biodiversity loss, and can reduce food security as well as water security.[3][1] It was estimated in 2007 that up to 40% of the world's agricultural land is seriously degraded,[4] with the United Nations estimating that the global economy could lose $23 trillion by 2050 through degradation.[5]

Definition

edit

As per the Millennium Ecosystem Assessment of 2005, land degradation is in defined as "the reduction or loss of the biological or economic productivity of drylands".[6] A similar definition states that land degradation is the "degradation, impoverishment and long-term loss of ecosystem services".[1]

It is viewed as any change or disturbance to the land perceived to be deleterious or undesirable.[7]

Scale

edit

According to the Special Report on Climate Change and Land of the Intergovernmental Panel on Climate Change in 2019: "About a quarter of the Earth's ice-free land area is subject to human-induced degradation (medium confidence). Soil erosion from agricultural fields is estimated to be currently 11 to 20 times (no-tillage) to more than 100 times (conventional tillage) higher than the soil formation rate (medium confidence)."[8]

 
A map created by "Save Soil" and backed by several UN agencies about the extent of possible soil degradation by the year 2050. The picture was created by "Save Soil" which permit to "download, display or print information from this website solely for non-commercial personal use" even though did not created specific licence

The United Nations estimate that about 30% of land is degraded worldwide, and about 3.2 billion people reside in these degrading areas, giving a high rate of environmental pollution.[2] About 12 million hectares of productive land—which roughly equals the size of Greece—is degraded every year. This happens because people exploit the land without protecting it.[9][10]

Estimates from 2021 say that two thirds of Africa's productive land area are severely affected by land degradation.[1]

The organization "Save Soil" backed by a number of UN agencies estimated that, in current curse, by 2050 95% of soil will be degraded.[11]

Types

edit
 
Potato field with soil erosion

In addition to the usual types of land degradation that have been known for centuries (water, wind and mechanical erosion, physical, chemical and biological degradation), four other types have emerged in the last 50 years:[12]

Overall, more than 36 types of land degradation can be assessed. All are induced or aggravated by human activities, e.g. soil erosion, soil contamination, soil acidification, sheet erosion, silting, aridification, salinization, urbanization, etc.

A problem with defining land degradation is that what one group of people might view as degradation, others might view as a benefit or opportunity. For example, planting crops at a location with heavy rainfall and steep slopes would create scientific and environmental concern regarding the risk of soil erosion by water, yet farmers could view the location as a favourable one for high crop yields.[13]

Causes

edit
 
The rate of global tree cover loss has approximately doubled since 2001, to an annual loss approaching an area the size of Italy.[14]

Land degradation is mainly derived by numerous, complex, and interrelated anthropogenic and/or natural proximate and underlying causes.[1] For example, in Ethiopia the country has been affected by chronic and ongoing land degradation processes and forms. The major proximate drivers are biophysical factors and unsustainable land management practices, while the underlying drivers are social, economic, and institutional factors.[1]

Land degradation is a global problem largely related to the agricultural sector, general deforestation and climate change. Causes include:

  • Land clearance, such as clearcutting, overlogging and deforestation
  • Agricultural activities such as:
    • Activities that lead to depletion of soil nutrients through poor farming practices such as exposure of naked soil after crop harvesting;
    • Monocultures which destabilize the local ecosystem;
    • Poor livestock farming practices such as overgrazing (the grazing of natural pastures at stocking intensities above the livestock carrying capacity);
    • Inappropriate irrigation[15]
  • Climate change because it can "exacerbate land degradation, particularly in low-lying coastal areas, river deltas, drylands and in permafrost areas"[8]
 
Soil erosion in a wheat field near Pullman, US

High population density is not always related to land degradation. Rather, it is the practices of the human population that can cause a landscape to become degraded.

Severe land degradation affects a significant portion of the Earth's arable lands, decreasing the wealth and economic development of nations. As the land resource base becomes less productive, food security is compromised and competition for dwindling resources increases, the seeds of famine and potential conflict are sown.

Climate change and land degradation

edit

According to the Special Report on Climate Change and Land of the Intergovernmental Panel on Climate Change (IPCC) climate change is one of the causes of land degradation. The report state that: "Climate change exacerbates land degradation, particularly in low-lying coastal areas, river deltas, drylands and in permafrost areas (high confidence). Over the period 1961–2013, the annual area of drylands in drought has increased, on average by slightly more than 1% per year, with large inter-annual variability. In 2015, about 500 (380–620) million people lived within areas which experienced desertification between the year 1980s and 2000s. The highest numbers of people affected are in South and East Asia, the circum Sahara region including North Africa, and the Middle East including the Arabian Peninsula (low confidence). Other dryland regions have also experienced desertification. People living in already degraded or desertified areas are increasingly negatively affected by climate change (high confidence)."[8] Additionally, it is reported that 74% of the poor are directly affected by land degradation globally.[16]

Significant land degradation from seawater inundation, particularly in river deltas and on low-lying islands, is a potential hazard that was identified in a 2007 IPCC report.

As a result of sea-level rise from climate change, salinity levels can reach levels where agriculture becomes impossible in very low-lying areas.

In 2009 the European Investment Bank agreed to invest up to $45 million in the Land Degradation Neutrality Fund (LDN Fund).[17][9] Launched at UNCCD COP 13 in 2017, the LDN Fund invests in projects that generate environmental benefits, socio-economic benefits, and financial returns for investors.[18] The Fund was initially capitalized at US$100 million and is expected to grow to US$300 million.[18]

In the 2022 IPCC report,[19] land degradation is responding more directly to climate change as all types of erosion and SOM declines (soil focus) are increasing.[20] Other land degradation pressures are also being caused by human pressures like managed ecosystems. These systems include human run croplands and pastures.[20]

Impacts

edit

Land degradation takes many forms and affects water and land resources. It can diminish the natural capacity of the land to store and filter water leading to water scarcity.[1]

The results of land degradation are significant and complex. They include lower crop yields, less diverse ecosystems, more vulnerability to natural disasters like floods and droughts, people losing their homes, less food available, and economic problems. Degraded land also releases greenhouse gases, making climate change worse.

Further possible impacts include:

  1. A temporary or permanent decline in the productive capacity of the land. This can be seen through a loss of biomass, a loss of actual productivity or in potential productivity, or a loss or change in vegetative cover and soil nutrients.
  2. Loss of biodiversity: A loss of range of species or ecosystem complexity as a decline in the environmental quality.
  3. Increased vulnerability of the environment or people to destruction or crisis.

Sensitivity and resilience

edit
 
Serious land degradation in Nauru after the depletion of the phosphate cover through mining

Sensitivity and resilience are measures of the vulnerability of a landscape to degradation. These two factors combine to explain the degree of vulnerability.[13] Sensitivity is the degree to which a land system undergoes change due to natural forces, human intervention or a combination of both. Resilience is the ability of a landscape to absorb change, without significantly altering the relationship between the relative importance and numbers of individuals and species that compose the community.[21] It also refers to the ability of the region to return to its original state after being changed in some way. The resilience of a landscape can be increased or decreased through human interaction based upon different methods of land-use management. Land that is degraded becomes less resilient than undegraded land, which can lead to even further degradation through shocks to the landscape.[22]

Prevention

edit

Sustainable land management

edit

Actions to halt land degradation can be broadly classified as prevention, mitigation, and restoration interventions.[1]

Sustainable land management has been proven in reversing land degradation. It also ensures water security by increasing soil moisture availability, decreasing surface runoff, decreasing soil erosion, leading to an increased infiltration, and decreased flood discharge.[1]

The United Nations Sustainable Development Goal 15 has a _target to restore degraded land and soil and achieve a land degradation-neutral world by 2030.[16] The full title of _target 15.3 is: "By 2030, combat desertification, restore degraded land and soil, including land affected by desertification, drought and floods, and strive to achieve a land degradation-neutral world."[23]

Public awareness and education

edit

Increasing public awareness about the importance of land conservation, sustainable land management, and the consequences of land degradation is vital for fostering behavioral change and mobilizing support for action. Education, outreach campaigns, and knowledge-sharing platforms can empower individuals, communities, and stakeholders to adopt more sustainable practices and become stewards of the land.[24]

See also

edit

References

edit
  1. ^ a b c d e f g h i j Dagnachew, Melku; Gebrehiwot, Solomon Gebreyohanis; Bewket, Woldeamlak; Alamirew, Tena; Charles, Katrina; Zeleke, Gete (2024). "Ensuring sustainable water security through sustainable land management: Research evidences for policy". World Water Policy. doi:10.1002/wwp2.12209. ISSN 2639-541X. Archived from the original on 21 July 2024 – via Wiley Online Library.   Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License
  2. ^ a b Le, Quang Bao; Nkonya, Ephraim; Mirzabaev, Alisher (2014). "Biomass Productivity-Based Mapping of Global Land Degradation Hotspots". SSRN Electronic Journal. doi:10.2139/ssrn.2465799. hdl:10419/106616. ISSN 1556-5068. S2CID 126829880.
  3. ^ Eswaran, H.; R. Lal; P.F. Reich (2001). "Land degradation: an overview". Responses to Land Degradation. Proc. 2nd. International Conference on Land Degradation and Desertification. NRCS Soils. New Delhi: Oxford Press. Archived from the original on 20 January 2012. Retrieved 5 February 2012.
  4. ^ Ian Sample (31 August 2007). "Global food crisis looms as climate change and population growth strip fertile land". The Guardian. Archived from the original on 29 April 2016. Retrieved 23 July 2008.
  5. ^ "Private sector urged to act as world faces $23 trillion loss from land degradation | UN News". news.un.org. 5 December 2024. Retrieved 18 December 2024.
  6. ^ Millennium Ecosystem Assessment, 2005. Ecosystems and Human Well-being: Desertification Synthesis. World Resources Institute, Washington, DC.
  7. ^ Johnson, D.L., S.H. Ambrose, T.J. Bassett, M.L. Garfield Bowen, D.E. Crummey, J.S. Isaacson, D.N. Johnson, P. Lamb, M. Saul, and A.E. Winter-Nelson. 1997. Meanings of environmental terms. Journal of Environmental Quality 26: 581–589.
  8. ^ a b c Summary for Policymakers. In: Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems (PDF). Intergovernmental Panel on Climate Change. 2019. p. 5. Archived (PDF) from the original on 17 February 2020. Retrieved 30 January 2020.
  9. ^ a b "Artificial intelligence makes restaurants and farms more sustainable". European Investment Bank. Archived from the original on 29 July 2021. Retrieved 29 July 2021.
  10. ^ "24 billion tons of fertile land lost every year, warns UN chief on World Day to Combat Desertification". UN News. 16 June 2019. Archived from the original on 28 June 2021. Retrieved 29 July 2021.
  11. ^ "95% of the Earth's Soil on Course to Be Degraded by 2050". Earth.com. Retrieved 22 December 2024.
  12. ^ Brabant Pierre, 2010. A land degradation assessment and mapping method. A standard guideline proposal Archived 7 July 2017 at the Wayback Machine. Les dossiers thématiques du CSFD. N°8. November 2010. CSFD/Agropolis International, Montpellier, France. 52 pp.
  13. ^ a b Stockings, Mike; Murnaghan, Niamh (2000), Land Degradation – Guidelines for Field Assessment, Norwich, UK: Earthscan Publications, pp. 7–15, archived from the original on 27 July 2021, retrieved 27 July 2021
  14. ^ Butler, Rhett A. (31 March 2021). "Global forest loss increases in 2020". Mongabay. Archived from the original on 1 April 2021. ● Data from "Indicators of Forest Extent / Forest Loss". World Resources Institute. 4 April 2024. Archived from the original on 27 May 2024. Chart in section titled "Annual rates of global tree cover loss have risen since 2000".
  15. ^ Oosterbaan, R.J. (1989), Effectiveness and Social/Environmental Impacts of Irrigation Projects: a Review (PDF), In: Annual Report 1988 of the International Institute for Land Reclamation and Improvement (ILRI), Wageningen, The Netherlands: ILRI, pp. 18–34, S2CID 654729, archived from the original on 11 July 2019, retrieved 26 July 2010
  16. ^ a b "Goal 15 _targets". UNDP. Archived from the original on 4 September 2017. Retrieved 24 September 2020.
  17. ^ "Land Degradation Neutrality (LDN) Fund – Our references – Our clients – innpact". www.innpact.com. Archived from the original on 27 September 2022. Retrieved 29 July 2021.
  18. ^ a b Chasek, Pamela; Akhtar-Schuster, Mariam; Orr, Barron Joseph; Luise, Anna; Rakoto Ratsimba, Harifidy; Safriel, Uriel (February 2019). "Land degradation neutrality: The science-policy interface from the UNCCD to national implementation". Environmental Science & Policy. 92: 182–190. Bibcode:2019ESPol..92..182C. doi:10.1016/j.envsci.2018.11.017. S2CID 158501714. Archived from the original on 22 January 2022. Retrieved 6 October 2021.
  19. ^ "Special Report on Climate Change and Land — IPCC site". Archived from the original on 21 June 2022. Retrieved 1 March 2022.
  20. ^ a b "Chapter 4 : Land Degradation — Special Report on Climate Change and Land". Archived from the original on 3 March 2022. Retrieved 1 March 2022.
  21. ^ Johnson, Douglas; Lewis, Lawrence (2007), Land Degradation; Creation and Destruction, Maryland, US: Rowman & Littlefield
  22. ^ Stocking, Michael A; Murnaghan, Niamh (5 November 2013). A Handbook for the Field Assessment of Land Degradation. doi:10.4324/9781849776219. ISBN 978-1-136-53369-3.
  23. ^ "Work of the Statistical Commission pertaining to the 2030 Agenda for Sustainable Development". Resolution adopted by the General Assembly on 6 July 2017 (Report). United Nations. 2017.
  24. ^ "Spreading Open and Inclusive Literacy and Soil Culture through Artistic Practices and Education". UNESCO. 28 June 2024. While soil scientists and land professionals have been ringing the alarm for the past decades, the lack of awareness and education of the general public about the importance of soils for humans and ecosystems has become a concern. This hinders the vitally important transition towards sustainable soil governance and highlights the need for enhanced soil literacy.
  NODES
Community 1
HOME 2
Intern 4
languages 1
mac 1
Note 1
os 53
text 1
web 1