Land degradation

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Serious land degradation in Nauru after the depletion of the phosphate cover through mining Karst following phosphate mining on Nauru.jpg
Serious land degradation in Nauru after the depletion of the phosphate cover through mining

Land degradation is a process in which the value of the biophysical environment also biochemical environment is affected by a combination of human-induced processes acting upon the land. [1] It is viewed as any change or disturbance to the land perceived to be deleterious or undesirable. [2] Natural hazards are excluded as a cause; however human activities can indirectly affect phenomena such as floods and bush fires.

Contents

Expert projections suggest that land degradation will be an important theme of the 21st century, impacting agricultural productivity, biodiversity loss, environmental change, and its effects on food security. [3] It is estimated that up to 40% of the world's agricultural land is seriously degraded. [4]

According to the Special Report on Climate Change and Land of the Intergovernmental Panel on Climate Change, "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)." [5]

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. [6] 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. [7] [8] 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. [9]

Consequences

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. There are four main ways of looking at land degradation and its impact on the environment around it:

  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. Action in the land's capacity to provide resources for human livelihoods. This can be measured from a base line of past land use.
  3. Loss of biodiversity: A loss of range of species or ecosystem complexity as a decline in the environmental quality.
  4. Shifting ecological risk: increased vulnerability of the environment or people to destruction or crisis. This is measured through a base line in the form of pre-existing risk of crisis or destruction.

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. [10]

Different types

Potato field with soil erosion A potato field with soil erosion.jpg
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: [11]

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.

Causes

The rate of global tree cover loss has approximately doubled since 2001, to an annual loss approaching an area the size of Italy. 20210331 Global tree cover loss - World Resources Institute.svg
The rate of global tree cover loss has approximately doubled since 2001, to an annual loss approaching an area the size of Italy.
Overgrazing by livestock can lead to land degradation Cattle.jpg
Overgrazing by livestock can lead to land degradation

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

Soil erosion in a wheat field near Pullman, US Erosion.jpg
Soil erosion in a wheat field near Pullman, US

Overcutting of vegetation occurs when people cut forests, woodlands and shrublands—to obtain timber, fuelwood and other products—at a pace exceeding the rate of natural regrowth. This is frequent in semi-arid environments, where fuelwood shortages are often severe.

Overgrazing is the grazing of natural pastures at stocking intensities above the livestock carrying capacity; the resulting decrease in the vegetation cover is a leading cause of wind and water erosion. It is a significant factor in Afghanistan. The growing population pressure, during 1980–1990, has led to decreases in the already small areas of agricultural land per person in six out of eight countries (14% for India and 21% for Pakistan).

Population pressure also operates through other mechanisms. Improper agricultural practices, for instance, occur only under constraints such as the saturation of good lands under population pressure which leads settlers to cultivate too shallow or too steep soils, plough fallow land before it has recovered its fertility, or attempt to obtain multiple crops by irrigating unsuitable soils.

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. Populations can be a benefit to the land and make it more productive than it is in its natural state. Land degradation is an important factor of internal displacement in many African and Asian countries. [14]

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

According to the Special Report on Climate Change and Land of the Intergovernmental Panel on Climate Change climate change is one of the causes of land degradation. The report state that: "Climate change exacerbates land degradation, particularly in lowlying 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)." [15] Additionally, it is claimed that 74% of the poor are directly affected by land degradation globally. [9]

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.

One way to consider climate change and land degradation is through the discipline of Land Change Science, which, among other things, tracks the long-term consequences of land degradation on the climate of a given area. By understanding the links between land degradation and climate change, scientists can better inform the creation of policies to reduce harm.

In 2009 the European Investment Bank agreed to invest up to $45 million in the Land Degradation Neutrality Fund (LDN Fund). [16] [7] 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. [17] The Fund was initially capitalized at US$100 million and is expected to grow to US$300 million. [17]

In the 2022 IPCC report, [18] land degradation is responding more directly to climate change as all types of erosion and SOM declines (soil focus) are increasing. [19] Other land degradation pressures are also being caused by human pressures like managed ecosystems. These systems include human run croplands and pastures. [19]

Landslides also come into effect which is the cause of intensive events such as individual rain storms. [19]

Sensitivity and resilience

Public awareness and education

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.

Sensitivity and resilience are measures of the vulnerability of a landscape to degradation. These two factors combine to explain the degree of vulnerability. [10] 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. [20] 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.

See also

Related Research Articles

<span class="mw-page-title-main">Arable land</span> Land capable of being ploughed and used to grow crops

Arable land is any land capable of being ploughed and used to grow crops. Alternatively, for the purposes of agricultural statistics, the term often has a more precise definition:

Arable land is the land under temporary agricultural crops, temporary meadows for mowing or pasture, land under market and kitchen gardens and land temporarily fallow. The abandoned land resulting from shifting cultivation is not included in this category. Data for 'Arable land' are not meant to indicate the amount of land that is potentially cultivable.

<span class="mw-page-title-main">Desertification</span> Process by which fertile areas of land become increasingly arid

Desertification is a type of gradual land degradation of fertile land into arid desert due to a combination of natural processes and human activities. This spread of arid areas is caused by a variety of factors, such as overexploitation of soil as a result of human activity and the effects of climate change. Geographic areas most affected are located in Africa, Asia and parts of South America. Drylands occupy approximately 40–41% of Earth's land area and are home to more than 2 billion people. Effects of desertification include sand and dust storms, food insecurity, and poverty.

<span class="mw-page-title-main">Soil erosion</span> Displacement of soil by water, wind, and lifeforms

Soil erosion is the denudation or wearing away of the upper layer of soil. It is a form of soil degradation. This natural process is caused by the dynamic activity of erosive agents, that is, water, ice (glaciers), snow, air (wind), plants, and animals. In accordance with these agents, erosion is sometimes divided into water erosion, glacial erosion, snow erosion, wind (aeolian) erosion, zoogenic erosion and anthropogenic erosion such as tillage erosion. Soil erosion may be a slow process that continues relatively unnoticed, or it may occur at an alarming rate causing a serious loss of topsoil. The loss of soil from farmland may be reflected in reduced crop production potential, lower surface water quality and damaged drainage networks. Soil erosion could also cause sinkholes.

<span class="mw-page-title-main">Topsoil</span> Top layer of soil

Topsoil is the upper layer of soil. It has the highest concentration of organic matter and microorganisms and is where most of the Earth's biological soil activity occurs.

<span class="mw-page-title-main">Environmental degradation</span> Any change or disturbance to the environment perceived to be deleterious or undesirable

Environmental degradation is the deterioration of the environment through depletion of resources such as quality of air, water and soil; the destruction of ecosystems; habitat destruction; the extinction of wildlife; and pollution. It is defined as any change or disturbance to the environment perceived to be deleterious or undesirable. The environmental degradation process amplifies the impact of environmental issues which leave lasting impacts on the environment.

<span class="mw-page-title-main">Human impact on the environment</span> Impact of human life on Earth and environment

Human impact on the environment refers to changes to biophysical environments and to ecosystems, biodiversity, and natural resources caused directly or indirectly by humans. Modifying the environment to fit the needs of society is causing severe effects including global warming, environmental degradation, mass extinction and biodiversity loss, ecological crisis, and ecological collapse. Some human activities that cause damage to the environment on a global scale include population growth, neoliberal economic policies and rapid economic growth, overconsumption, overexploitation, pollution, and deforestation. Some of the problems, including global warming and biodiversity loss, have been proposed as representing catastrophic risks to the survival of the human species.

<span class="mw-page-title-main">Environmental issues in Africa</span>

African environmental issues are caused by human impacts on the natural environment and affect humans and nearly all forms of life. Issues include deforestation, soil degradation, air pollution, water pollution, garbage pollution, climate change and water scarcity. These issues result in environmental conflict and are connected to broader social struggles for democracy and sovereignty.

<span class="mw-page-title-main">Biomass (energy)</span> Biological material used as a renewable energy source

Biomass, in the context of energy production, is matter from recently living organisms which is used for bioenergy production. Examples include wood, wood residues, energy crops, agricultural residues including straw, and organic waste from industry and households. Wood and wood residues is the largest biomass energy source today. Wood can be used as a fuel directly or processed into pellet fuel or other forms of fuels. Other plants can also be used as fuel, for instance maize, switchgrass, miscanthus and bamboo. The main waste feedstocks are wood waste, agricultural waste, municipal solid waste, and manufacturing waste. Upgrading raw biomass to higher grade fuels can be achieved by different methods, broadly classified as thermal, chemical, or biochemical.

<span class="mw-page-title-main">Oasification</span> Antonym to desertification by soil erosion

In hydrology, oasification is the antonym to desertification by soil erosion. This technique has limited application and is normally considered for much smaller areas than those threatened by desertification.

<span class="mw-page-title-main">Soil carbon</span> Solid carbon stored in global soils

Soil carbon is the solid carbon stored in global soils. This includes both soil organic matter and inorganic carbon as carbonate minerals. It is vital to the soil capacity in our ecosystem. Soil carbon is a carbon sink in regard to the global carbon cycle, playing a role in biogeochemistry, climate change mitigation, and constructing global climate models. Natural variation such as organisms and time has affected the management of carbon in the soils. The major influence has been that of human activities which has caused a massive loss of soil organic carbon. An example of human activity includes fire which destroys the top layer of the soil and the soil therefore get exposed to excessive oxidation.

Peter Bullock was a soil scientist whose initial work in the field of soil micromorphology preceded an interest in land degradation. His advocacy of the need to treat soil as a sustainable resource led to his appointment to the Intergovernmental Panel on Climate Change. Bullock contributed to the reports of the IPCC, which was awarded the Nobel Peace Prize in 2007.

The environmental impact of agriculture is the effect that different farming practices have on the ecosystems around them, and how those effects can be traced back to those practices. The environmental impact of agriculture varies widely based on practices employed by farmers and by the scale of practice. Farming communities that try to reduce environmental impacts through modifying their practices will adopt sustainable agriculture practices. The negative impact of agriculture is an old issue that remains a concern even as experts design innovative means to reduce destruction and enhance eco-efficiency. Though some pastoralism is environmentally positive, modern animal agriculture practices tend to be more environmentally destructive than agricultural practices focused on fruits, vegetables and other biomass. The emissions of ammonia from cattle waste continue to raise concerns over environmental pollution.

At the global scale sustainability and environmental management involves managing the oceans, freshwater systems, land and atmosphere, according to sustainability principles.

Soil governance refers to the policies, strategies, and the processes of decision-making employed by nation states and local governments regarding the use of soil. Globally, governance of the soil has been limited to an agricultural perspective due to increased food insecurity from the most populated regions on earth. The Global Soil Partnership, GSP, was initiated by the Food and Agriculture Organization (FAO) and its members with the hope to improve governance of the limited soil resources of the planet in order to guarantee healthy and productive soils for a food-secure world, as well as support other essential ecosystem services.

<span class="mw-page-title-main">Lindsay Stringer</span>

Lindsay C. Stringer is a Professor in Environment and Development at the University of York.

<span class="mw-page-title-main">Soil compaction (agriculture)</span> Decrease in porosity of soil due to agriculture

Soil compaction, also known as soil structure degradation, is the increase of bulk density or decrease in porosity of soil due to externally or internally applied loads. Compaction can adversely affect nearly all physical, chemical and biological properties and functions of soil. Together with soil erosion, it is regarded as the "costliest and most serious environmental problem caused by conventional agriculture."

<span class="mw-page-title-main">Soil regeneration</span>

Soil regeneration, as a particular form of ecological regeneration within the field of restoration ecology, is creating new soil and rejuvenating soil health by: minimizing the loss of topsoil, retaining more carbon than is depleted, boosting biodiversity, and maintaining proper water and nutrient cycling. This has many benefits, such as: soil sequestration of carbon in response to a growing threat of climate change, a reduced risk of soil erosion, and increased overall soil resilience.

<span class="mw-page-title-main">Carbon farming</span> Agricultural methods that capture carbon

Carbon farming is a set of agricultural methods that aim to store carbon in the soil, crop roots, wood and leaves. The technical term for this is carbon sequestration. The overall goal of carbon farming is to create a net loss of carbon from the atmosphere. This is done by increasing the rate at which carbon is sequestered into soil and plant material. One option is to increase the soil's organic matter content. This can also aid plant growth, improve soil water retention capacity and reduce fertilizer use. Sustainable forest management is another tool that is used in carbon farming. Carbon farming is one component of climate-smart agriculture. It is also one of the methods for carbon dioxide removal (CDR).

<span class="mw-page-title-main">Special Report on Climate Change and Land</span> IPCC report

The United Nations' Intergovernmental Panel on Climate Change's (IPCC) Special Report on Climate Change and Land (SRCCL), also known as the "Special Report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems", is a landmark study from 2019 by 107 experts from 52 countries. The SRCCL provides a comprehensive overview of the entire land-climate system for the first time and decided to enlist land as a "critical resource". The IPCC's 50th session (IPCC-50) formally adopted the SRCCL's Summary for policymakers (SPM) and approved the underlying report. The SPM and the full text of Special Report on Climate Change and Land—in an unedited form—were released on 8 August 2019. The report is over 1,300 pages long and includes the work of 107 experts from 52 countries.

<span class="mw-page-title-main">Desertification in Africa</span> Causes and effects of land degradation

Desertification in Africa is a form of land degradation that involves the conversion of productive land into desert or arid areas. This issue is a pressing environmental concern that poses a significant threat to the livelihoods of millions of people in Africa who depend on the land for subsistence. Geographical and environmental studies have recently coined the term desertification. Desertification is the process by which a piece of land becomes a desert, as the word desert implies. The loss or destruction of the biological potential of the land is referred to as desertification. It reduces or eliminates the potential for plant and animal production on the land and is a component of the widespread ecosystem degradation. Additionally, the term desertification is specifically used to describe the deterioration of the world's drylands, or its arid, semi-arid, and sub-humid climates. These regions may be far from the so-called natural or climatic deserts, but they still experience irregular water stress due to their low and variable rainfall. They are especially susceptible to damage from excessive human land use pressure. The causes of desertification are a combination of natural and human factors, with climate change exacerbating the problem. Despite this, there is a common misconception that desertification in Africa is solely the result of natural causes like climate change and soil erosion. In reality, human activities like deforestation, overgrazing, and unsustainable agricultural practices contribute significantly to the issue. Another misconception is that, desertification is irreversible, and that degraded land will forever remain barren wastelands. However, it is possible to restore degraded land through sustainable land management practices like reforestation and soil conservation. A 10.3 million km2 area, or 34.2% of the continent's surface, is at risk of desertification. If the deserts are taken into account, the affected and potentially affected area is roughly 16.5 million km2 or 54.6% of all of Africa. 5.7 percent of the continent's surface is made up of very severe regions, 16.2 percent by severe regions, and 12.3 percent by moderate to mild regions.

References

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Further reading