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kumaradhikaryofficial · 1 year

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No Land, No Life! Stop Land Degradation.

Land which covers 30% of the Earth’s surface is literally the ground beneath our feet. It is significant for our survival as it contains a very precious natural resource-soil.

Soil is a combination of weathered rocks and minerals along with decomposed plants and animals (known as organic matter or humans), small living animals, plants, fungi, bacteria, other microscopic organisms, water and air. A great variety of organisms lives in the soil like earth-worms, millipedes, insects. Thus, the biotic components of soil comprise of micro-organisms, flora and fauna. The abiotic components are weathered rock, dead organic matter, air and water in the pore spaces. All these components have functional linkages between them. Therefore, healthy soil is a complex ecosystem capable of sustaining huge variety of life.

Land provides principal basic of human well-being and livelihood. Soil supports tremendous biodiversity and provides ecosystem services like food production, carbon sequestration, decomposition of organic matter and biogeochemical cycling (like carbon, nitrogen, oxygen, phosphorous etc). It helps in water infiltration into the ground water aquifers and plays an important role in hydrological cycling. Soil is a huge carbon sink and thus, plays an important role in climate system.

The pressures on global land resources are tremendous in the present times. Rapid population growth and rising levels of consumption are placing larger demands on the world’s land-based natural capital.

Major pressures on land include:

Changes in the Land Use - Conversion of natural ecosystems like forests to other uses like agriculture expansion, urbanisation, mining etc.

Land Use Intensification - To meet the food demands of increasing human population and consumption, land use intensification in agriculture has happened.

Unsustainable Land Use Practices - In form of over-application of chemical fertilisers; over irrigation by ground water to meet the food security demands of human population.

Land Degradation is defined as persistent reduction in the capacity of land to support biodiversity, ecosystem services and human needs. The process of land degradation is gradual. The major symptoms of land degradation are long term reduction or loss in biological productivity, ecological integrity or value to humans.

Major types of land degradation include:

Soil Erosion - Loss of top cover of the soil either by the action of wind, or the water of gravity.

Soil Salinisation - Saline and alkaline encrustations consisting of salts of sodium, potassium and magnesium appear on the top layers of the soil through capillary action.

Soil Acidification - Excessive build-up of hydrogen or aluminium cations in soil due to long-term rainfall or acid deposition due to mining activities.

Soil Pollution - Presence of chemicals in soils that are either out of place or higher than normal concentrations.

An extreme form of land degradation in aris, semi-arid and dry sub-humid regions of the world is called Desertification. Desertification is therefore, the deterioration of land in arid, semi-arid and dry sub-humid regions (also called dryland) of the world due to climatic variations and human activities, Some of the regions most vulnerable to desertification are Sub-Saharan Africa, drier regions of South America and Asia.

As per United Nations (UN), roughly 2.5 billion people - around 30% of the world’s population live in dryland areas, which cover more than 40% of the world’s land surface.

Major causes of land degradation include both natural and human-induced causes. These include the following:

Prolonged Droughts - Recurrent droughts induce water stresses in soil. Reduced soil moisture makes soil vulnerable to soil erosion. Long droughts are one of the major reasons for land degradation globally. That’s why land degradation is most pervasive in the arid, semi-arid and dry sub-humid regions of the world which receive lesser rainfall and are drought-prone regions of the world. Such lands are called marginal lands where rainfall is insufficient to support crops over the long term. Marginal lands are the soils of arid, semi-arid and dry sub-humid regions of the world where the annual average rainfall is less than 100 cm.

Climate Change - It acts as an additional stress on land in multiple ways. Global warming exacerbates heat stresses and droughts. Warming has resulted in an increased frequency, intensity and duration of heat waves in most regions. It thereby amplifies deficits in soil moisture. Increased heatwaves threaten the already drought-prone regions of Africa, West Asia, many parts of South America, the Mediterranean etc by reducing the overall vegetative and tree growth. Vegetation and soil moisture provide vital safeguards against soil erosion and thus land degradation.

Deforestation - With the increased demand for land for multiple purposes, the incidence of deforestation has increased. Soils devoid of vegetative cover have high erodibility and thus, high rates of soil erosion cause land degradation.

Faulty Agricultural Practices - A few examples of bad farming practices include:

Over-irrigation in arid and semi arid areas causes soil salinisation. When irrigation water evaporates, it leaves behind salts residue. In drier regions like arid and semi-arid regions of the world, the evaporation rates are high and rainfall is insufficient to leach down the soluble salts. Therefore, these regions are more susceptible to soil salinisation induced land degradation.

Excessive use of chemicals like chemical fertilisers, pesticides etc. which can chemically poison the soil.

Overgrazing by Cattle - On marginal lands, rainfall is just barely enough to enable land to produce more vegetation than a desert. In such regions, even light grazing by cattle can be too much grazing which causes soil erosion.

Disposal of Industrial Wastes on Land - Improper disposal of toxic chemicals from industries can contaminate the soil. This is one of the major causes of land degradation due to human activities worldwide.

United Nations (UN) does periodic global assessment of land degradation. Incidence of land degradation as per UN’s 2019 assessment is as follows:

The total degraded area varies from less than 1 billion hectares to over 6 billion hectares globally.

Land degradation due to human activities is adversely impacting the well-being of at least 3.2 billion people.

Land degradation also negatively impacts ecosystem functioning. There is about a 5% reduction in global net primary productivity due to land degradation.

Between 2000 and 2009, land degradation caused global emissions of 3.6-4.4 billion tonnes of carbon dioxide annually.

Soil organic carbon (SOC) is a crucial indicator of soil health. However, it declines with an increase in unsustainable land management practices and land conversion. Over the past part past two centuries, SOC has seen about an 8% loss globally.

Degraded lands offer little economic value or biological productivity. Major consequences of land degradation and desertification are felt both across natural and human systems.

Impacts of land degradation and desertification on natural systems are -

Biodiversity Loss and Loss of Ecosystem Services - land degradation makes soil less fertile. This reduces the vegetative cover over soil. In turn, the floral and faunal species diversity also declines.

Any decline in biological diversity negatively affects ecosystem services as well. For example, degraded soils have poor water infiltration through them which reduces the recharge of ground water aquifer. Similarly, carbon sequestration capacity of such soils declines considerably. This exacerbates the existing climate change.

As per Land Degradation and Restoration Assessment by IPBES (June 2018), land degradation has already had a pronounced impact on ecosystem functions worldwide amounting to a %% reduction in total global net primary productivity. It costs more than 10% of the annual global gross product in loss of biodiversity and ecosystem services.

Climate Change - Land acts both as a carbon sink and a carbon source. It is a carbon sink as it absorbs carbon dioxide during photosynthesis. However, when decomposition of dead organic matter takes place in soils, land emits greenhouse gases.

Climate change exacerbates land degradation. Degraded lands have a compromised ability to support vegetative growth and therefore, reduced ability to act as a carbon sink. Between 2000 and 2009, land degradation was responsible for annual global emissions of 3.6 - 4.4 billion tons of carbon dioxide.

Impact of land degradation and desertification on human systems are-

Threats to Food Security and Livelihood Loss - Land degradation is potent to disrupt the agricultural food production and threaten food security. As per UN, by 2050, global food production would need to increase by 50% to feed the more than 9 billion people expected to live on our planet. However, it becomes challenging as land degradation and climate change together are predicted to reduce crop yields by an average of 10% globally. Reduced food security worsens health for por across the world.

Degraded lands also mean livelihood loss for the poorer sections like farmers and pastoralists. They are dependent on ecosystem services and natural capital for their sustenance.

2. Increased Conflicts and Forced Displacement - In dryland areas, food insecurity and loss of livelihood exacerbate poverty. This often results in resource-driven conflicts. As per the UN, every 5% loss of gross domestic product, itself partly caused by degradation, is associated with a 12% increase in the likelihood of violent conflict. Land degradation and climate change are likely to force 50 to 700 million people to migrate by 2050.

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