Land degradation, desertification and mountains

The first principle

Soil is a thin, slowly made skin: a few centimetres can take centuries to form from rock, yet a single storm or season of bare ground can strip it away. Land stays productive only while a cover of plants holds the soil, feeds it organic matter and lets rain soak in, so anything that removes that cover faster than nature can rebuild it degrades the land. Climate decides how fast the damage can happen, wind in deserts and running water on slopes, but it is the removal of cover, mostly by people, that starts it.

The core

What land degradation and desertification mean

• Land degradation is any lasting fall in the land's biological or economic productivity, through soil erosion, salinity, waterlogging, loss of vegetation or pollution.
• The United Nations Convention to Combat Desertification (UNCCD, 1994) defines desertification as land degradation in arid, semi arid and dry sub humid areas resulting from climatic variations and human activities. It does not mean deserts spreading like a tide; it means patches of land everywhere losing their ability to support life.

Causes

• Climatic. Droughts, erratic rain and higher temperatures dry the soil and kill vegetation, which leaves land open to wind and water.
• Human. Overgrazing, clearing of forests and scrub for fuel and farms, over irrigation without drainage that raises salt to the surface, mining that strips topsoil, and shorter fallow periods in shifting cultivation.

The role of aeolian processes

Aeolian processes are the work of wind, which dominates where vegetation is sparse and the soil is dry and loose. Wind moves grains in three ways: fine dust is lifted high in suspension, sand grains hop along in saltation, and coarser grains roll in surface creep. The amount of sand moved rises sharply, roughly with the cube of wind speed, once a threshold is crossed, so a few dry, stormy days do most of the damage.

• Deflation blows away the fine, fertile particles of topsoil, which carry most of its organic matter and nutrients, and leaves coarse sand or a stony desert pavement behind.
• Abrasion by wind driven sand scours crops, seedlings, fences and rock.
• Dune migration buries farms, roads, railways and canals; in western Rajasthan shifting sand has repeatedly choked stretches of the Indira Gandhi Canal.
• Dust storms carry nutrients far away and cause health and aviation hazards, while the dust settles elsewhere as loess, which can be fertile, as on the Loess Plateau of China.
• Cases. The American Dust Bowl of the 1930s followed the ploughing of the Great Plains grasslands before a drought; in the Sahel, droughts of the 1970s and 1980s combined with overgrazing; and the drying of the Aral Sea left a bed from which salt and dust storms now spread over farms.

Wind and degradation also feed each other: bare ground lets wind erode, and erosion keeps the ground bare, which is why stabilising dunes with grasses and shelterbelts is so effective.

Dimensions

Desertification does not have climate boundaries

Although the UNCCD definition covers drylands, degradation that cuts land productivity happens in every climate, because the cause is misuse, not only dryness.

• In the very humid north east, shorter jhum cycles leave slopes bare under heavy rain.
• In the Western Ghats and Goa, mining and clearing expose laterite, which hardens into barren crust.
• In irrigated Punjab and Haryana, canal water without drainage has caused waterlogging and salinity.
• In the Himalaya, road cutting and deforestation trigger landslides.

The Space Applications Centre of the Indian Space Research Organisation (ISRO), in its Desertification and Land Degradation Atlas (2021), found that water erosion, not wind, is the leading process of degradation in India, which confirms that the problem is not limited to deserts.

In practice

India's degraded land

• About 97.85 million hectares, nearly 30 per cent of India, was degraded in 2018 to 2019. Rajasthan, Maharashtra, Gujarat, Ladakh, Jharkhand and Odisha have the largest degraded areas, while the share rose fastest in Delhi, Tripura, Nagaland and Himachal Pradesh.

Human induced land use changes and their consequences

• Urban sprawl spreads over the most fertile farmland around cities and fills lakes and floodplains, which causes urban floods, falling groundwater recharge and urban heat islands.
• Farm expansion and intensification pushed farming into forest edges and grasslands, while paddy with free power in semi arid Punjab mined groundwater and left soils compacted and short of organic carbon.
• Mining in the coal and iron ore belt of Jharkhand, Odisha and Chhattisgarh strips forest and topsoil, leaves overburden dumps and acid drainage, and displaces tribal communities.
• Dams and canals submerge forests and villages upstream and waterlog command areas downstream.
• Infrastructure such as highways and industrial corridors fragments forests and wildlife habitat.
• Overall consequences include soil erosion, groundwater decline, more intense floods, biodiversity loss and release of soil and forest carbon; even though India's forest cover holds at about 21.76 per cent of its area (India State of Forest Report 2023), dense natural forest is often replaced by plantations of lower ecological value.

Restoration commitments and schemes

• At the UNCCD meeting in New Delhi (COP14, September 2019), India raised its Bonn Challenge pledge to restore 26 million hectares of degraded land by 2030 and committed to land degradation neutrality, meaning new degradation is matched by restoration.
• The Aravalli Green Wall Project (Ministry of Environment, Forest and Climate Change, March 2023) plans a 5 km wide green belt along the Aravalli range across Gujarat, Rajasthan, Haryana and Delhi to stop the eastward spread of the Thar's sand and dust.
• The Watershed Development Component of the Pradhan Mantri Krishi Sinchayee Yojana (Ministry of Rural Development) treats rainfed land with contour bunds, check dams and plantations.

Restoring mountains from development and tourism

• Joshimath (January 2023). Cracks spread through hundreds of houses in this Uttarakhand town, built on old landslide debris; unplanned construction, poor drainage that let water seep into loose ground, and nearby tunnelling were blamed, and families were relocated.
• Char Dham road widening. Cutting steep, fragile slopes for wider roads triggered fresh landslides; the Supreme Court in December 2021 allowed wider roads for defence needs but asked for oversight of slope safety.
• Hydropower and tourism. Dense hydropower cascades on the Alaknanda and Bhagirathi, and peak season crowds in towns like Manali, Shimla and Mussoorie, overload water supply, sewage and solid waste systems; in 2023 to 2024 the Supreme Court asked for studies of the carrying capacity of Himalayan states and towns.
• What has worked. Sikkim became a fully organic state in 2016, restricts plastics and regulates tourism to fragile areas through permits; community managed forests such as the van panchayats of Uttarakhand keep slopes covered.

Issues and way forward

• Fragmented responsibility. Land, water, forest and agriculture sit with different departments, so restoration is uneven; the New Delhi Declaration (2019) called for integrated land use planning that includes all of them.
• Dryland grazing commons lost. Common grazing land is encroached or fenced, which concentrates livestock on what remains; restoring commons under panchayat control, as many watershed programmes recommend, eases the pressure.
• Development without hazard maps. Mountain towns grow on slopes no one has assessed; the National Mission for Sustaining the Himalayan Ecosystem (NMSHE, 2010) under the National Action Plan on Climate Change (NAPCC) and expert reports after Joshimath urge mandatory geological and carrying capacity studies before new projects.
• Tourism beyond limits. Caps on vehicles, permit systems and requirements to carry waste back down, as Sikkim and some trekking routes use, need wider adoption with homestays that keep income local.

Common confusions

• Desertification and desert expansion. Desertification is loss of productivity in drylands, which can happen in patches far from any desert.
• Land degradation and desertification. All desertification is land degradation, but degradation in humid regions falls outside the UNCCD definition of desertification.
• Deflation and abrasion. Deflation removes loose particles; abrasion wears surfaces with particles the wind carries.

For the exam

• Keyword bank: UNCCD, desertification, deflation, abrasion, saltation, surface creep, dune migration, loess, salinisation, waterlogging, land degradation neutrality, Bonn Challenge, Aravalli Green Wall, carrying capacity, Joshimath subsidence, NMSHE.
• Previous year questions: Practise the previous year questions on this topic →
• Use in an answer:
  • Introduction (data): About 97.85 million hectares, nearly 30 per cent of India's land, was degraded in 2018 to 2019, according to ISRO's Desertification and Land Degradation Atlas.
  • Introduction (judgement, quote or report): The UNCCD defines desertification as degradation from both climate and human activity, which places the remedy largely in human hands.
  • Conclusion: Land degradation is reversible where cover is restored and people share the benefits, so the 26 million hectare target must be met through communities, not plantations alone.
  • Conclusion: Mountains give India its water and its stability; development there must follow the limits of the slope, not the demand of the season.