Land degradation can exacerbate climate change and threaten agricultural productivity, water quality, biodiversity, sustainable development, and the living conditions of humans and wildlife, among other effects. Globally, a third of our land is degraded, affecting three billion people, and it is expected to worsen with rising demand for food.
As a signatory to the United Nations Convention to Combat Desertification, India is committed to reducing its land degradation and desertification. In fact, India’s goal is to achieve land degradation neutral status by 2030 whereby increases in land degradation would be offset by gains in land reclamation.
To address this issue, ISRO’s Space Applications Centre in Ahmedabad had released the results of a project in 2016 in the form of an Atlas mapping the extent of land degradation and desertification across the country, including the processes involved, the severity, and the changes in degradation. Not only does this Atlas facilitate India’s reporting to the United Nations Convention to Combat Desertification, it also highlights vulnerable areas for mitigation to policy makers, managers, planners, and researchers.
The report-cum-atlas showed that during 2011-2013, the most recent time period to be quantified, 29.3% of the country was undergoing land degradation. Compared with 2003-2005, the country experienced a 0.57% increase in land degradation and more land has been degraded than reclaimed. A few states were afflicted with more than 50% of their area under desertification. The increase in degradation compared with 2003-2005, was high for Delhi, Himachal Pradesh, and the northeastern states while four states showed a drop in degradation.
Better regulation of lands and stepping up watershed management initiatives will help combat the rising trend of degradation, experts say.
What is land degradation?
According to the United Nations Convention to Combat Desertification, land degradation is the “reduction or loss of biological or economic productivity..resulting from land uses or from a process or combination of processes, including...human activities.” When land degradation occurs in dryland areas, more specifically arid, semi-arid and dry sub-humid areas, it is referred to as desertification. Around 69% of India falls under drylands.
“The universal definition is the processes of land degradation that varies with the time and space,” explained Milap Sharma, a professor at the Centre for the Study of Regional Development at Jawaharlal Nehru University, New Delhi, who was part of the project. “The basic definition of land degradation which we used to prepare the Atlas is deterioration of the original quality of land and deterioration or total loss of the production capacity of the soil.”
Land degradation is driven by both by changes in climate or human activities. S Dharumarajan, a scientist at the Indian Council of Agricultural Research-National Bureau of Soil Survey and Land Use Planning in Bengaluru, who was involved in the project, pointed out. “Overexploitation of natural resources is the main reason for increasing land degradation in India,” he said.
The cost of land degradation can be substantial for India where agriculture is a large contributor to the country’s Gross Domestic Product. As a result, lost productivity can weigh heavily on the economy. A study by Delhi-based The Energy and Resources Institute or TERI estimated that the economic losses from land degradation and change of land use in 2014-’15 stood at 2.54% of India’s GDP or Rs 3,177.39 billion (Rs 317,739 crore or $46.9 billion) for that year. Land degradation alone accounted for 82% of those costs.
ISRO’s Atlas maps degradation and desertification from Indian Remote Sensing Satellite Advanced Wide Field Sensor or AWiFS data at a scale of 1:500,000 during 2003-2005 and 2011-2013 for all Indian states including the processes of degradation (ie water erosion, wind erosion, etc), their severity levels, and the changes between the two time frames – a period of eight years.
Funded by the Ministry of Environment, Forest and Climate Change and led by ISRO’s Space Applications Centre, the project involved a team of almost 100 scientists and staff members from 19 state government departments and academic institutes throughout the country.
The Atlas classifies the type of land cover, which included forest or plantation, agriculture, grassland, scrubland, barren, rocky area, sandy area, glacial, periglacial, and others. In addition, ground truthing or field observations were performed to ascertain that the satellite images were consistent with features on the ground.
In the Atlas, the processes of degradation/desertification are listed as vegetation degradation from deforestation, forest-blanks, shifting cultivation and grazing or grassland; water erosion resulting in the loss of soil cover mainly due to rainfall and surface runoff water; wind erosion causing the spread of sand which can erode soil; salinity of soils in cultivated areas due to excess evapotranspiration, drought, excess irrigation, and overuse of fertilisers; waterlogging or the accumulation of standing water for long periods caused by floods, excess irrigation, and incorrect planning of drainage; frost shattering referring to the breakdown of rocks because of differences in temperature; frost heaving where ice lens form under the soil; mass movement delineating the movement of masses of soil and rock due to gravity; and manmade causes such as mining, quarrying, brick kilns, industrial effluents, city waste, and urban agglomeration. These are further classified into their level of severity, either high or low.
Increase in degradation and desertification India-wide
In 2011-2013, India’s land degradation area totaled 29.3% of India’s total land area, representing an area of 96.4 million hectares. This is an increase of 0.57% compared with 2003-2005, which amounts to 1.87 mha – an area larger than the state of Nagaland. Although 1.95 mha of land was reclaimed or restored between 2003-2005 and 2011-2013, 3.63 mha of productive land degraded during this period.
“Land reclamation is bringing back the degraded land into its former state by adopting suitable management practices,” explained Dharumarajan.
The top processes leading to degradation/desertification in the country in both time periods were water erosion (10.98% in 2011-2013) followed by vegetation degradation (8.91%) and wind erosion (5.55%). Overall, the areas affected by vegetation and water erosion increased by 1.02 mha and 0.49 mha respectively in 2011-2013, while there was a slight drop in the total area degraded due to wind erosion and salinity, indicating improvement.
The area under desertification (dryland areas) was 82.64 mha in 2011-2013, which rose by 1.16 mha from 2003-2005. While wind erosion was the main process leading to desertification in the arid regions, vegetation degradation and water erosion dominated in the semi-arid and dry sub-humid regions.
Land degradation increased in most states
In terms of India’s total geographical area, the states of Rajasthan, Gujarat, Maharashtra, Jammu and Kashmir, and Karnataka have the highest area of lands undergoing degradation/desertification, amounting to 18.4% (out of India’s total 29.3%) while all the other states each had less than 2% of degraded lands.
But when considering the area within the states, Jharkhand followed by Rajasthan, Delhi, Gujarat, and Goa, had the highest area of degraded lands, representing more than 50% of their area. In comparison, the land area undergoing degradation/desertification in Kerala, Assam, Mizoram, Haryana, Bihar, Uttar Pradesh, Punjab, and Arunachal Pradesh was less than 10%.
Sharma explained that Rajasthan and Gujarat are large states with desert regions featuring an arid climate while “Delhi and Goa are comparatively smaller states, but overexploitation leads to a higher area under desertification.”
Overall, land degradation/desertification in 87% of 30 states increased from 2003-2005 to 2011-2013. Four states, however, improved slightly in their degradation status over the eight-year period. Among these, Uttar Pradesh had the highest restoration of 1.27%, mainly due to a drop in salinity, while the other three – Rajasthan, Odisha, and Telangana – improved by less than 1%.
Delhi had the third highest level of desertification (60.60% of the state) in the country and it also experienced the highest increase in land degradation (+11.03% ) over the eight-year period from 2003-2005. “In the case of Delhi it is not strictly desertification, but prime land degradation arising from settlement growth, which turns productive areas into non-productive ones,” explained Sharma.
Desertification in the northern states such as Himachal Pradesh (+4.55%) and Jammu & Kashmir (+1.94% ) rose more compared with the eastern states such as Bihar and West Bengal both of which experienced an increase of less than 1% in land degradation. According to Sharma, the “harsh climate and hilly terrains in Himachal Pradesh and Jammu & Kashmir are dominated by physical processes” such as slope erosion, mass-movement, and frost shattering.
The northeast part of the country had notably large increases in land degradation over the eight years from 2003-2005. Land degradation in the states of Nagaland, Tripura, and Mizoram shot up by 8.71%, 10.47%, and 4.34% respectively. In fact, Tripura and Nagaland had the second and third highest increase in degradation country-wide. The driving force for the sharp rise in these states was mainly because of a surge in vegetal degradation of forests.
This may be linked to “low or lack of watershed management interventions in the region from the beginning,” said V Ratna Reddy, Director of Livelihoods and Natural Resource Management Institute who was the author of a 2003 article on land degradation in India.
In contrast to the north and northeast, degradation/desertification in the southern states rose by less than 1% from 2003-2005 to 2011-2013. Dharumarajan explains that “unlike the northern states like Rajasthan or Gujarat” that feature arid climates, “southern states are mostly under semi-arid and dry sub-humid regions where the land degradation process is low.” But he warns that recently “due to overexploitation of land resources and mismanagement, desertification/land degradation processes in the southern states are growing at a faster rate.”
Among the southern states, Telangana showed an improvement in the area undergoing degradation/desertification by 0.52%. This is mainly because of a drop in the area of un-irrigated agricultural lands featuring low severity of water erosion, which is influenced by land management practices, says Dharumarajan. “But the main problem in Telangana is increasing salinity which is due to bringing non-conventional areas into irrigated agriculture,” he adds.
Varying degradation estimates and definitions
Surinder S. Kukal, a professor and dean of the College of Agriculture at Punjab Agricultural University, Ludhiana, said that the current estimation of land degradation at 29.3% is much lower compared with an earlier 1994 estimate of 57% by the National Bureau of Soil Survey and Land Use Planning.
This variation, according to Dharumarajan, arises due to differences in methodologies and definitions. The earlier estimate was likely based on extrapolation of sample surveys but the most recent figure is based on high-resolution remote sensing data, he points out.
Kukal has some concerns about the classification of the processes of degradation. He points out that the process of vegetation degradation leads to water and wind erosion. In other words, “the water and wind erosion are the outcomes of vegetation depletion.” And, although manmade degradation is stated separately in the Atlas, he believes that most land degradation is manmade.
“It all started when nomad humans started animal and crop husbandry by destroying natural vegetation to pave the way for present-day agricultural lands,” he stated. The best example, he says, is the practice of shifting cultivation in the northeast. Man-made degradation continues until today, he asserts, with agricultural lands being converted into settlements, industries, and highways.
“The impact of land degradation varies with time and space. It depends on the intensity and amount of rains which cause soil erosion by water,” Kukal says. “The increase/decrease in area under land degradation does not matter anymore because of the severity of various components of land degradation. The mudslides in Jammu & Kashmir (Ladakh) and Uttarakhand during the last few years are sufficient to remind us that things are going from bad to worse every year,” he said.
One of the reasons for the mudslides, explained Kukal, is “deforestation in the catchment areas of many natural and manmade reservoirs,” which “has led to their decreased capacity to hold water in them due to unabated soil erosion by water in the catchment areas.”
Reclaiming degraded lands
So what needs to be done to reclaim degraded lands?
According to Reddy, to combat soil loss by water erosion, which is the largest process leading to land degradation in India, and to restore degraded lands, there is a need to initiate watershed interventions immediately. Watershed management initiatives include afforestation and other programmes aimed at conserving soil and water.
“Watershed management has been dropped from the priority of natural resource management initiatives over the past five years at the national and state levels,” Reddy noted. “This is not a good sign for NRM [natural resource management], given that water erosion is on the rise. Systematic implementation of watershed interventions should be a long-term priority in order to check soil erosion, improve soil moisture, increase recharge, stabilise river basins (catchments) and making agriculture and communities climate resilient.”
Indeed, “watershed management programmes have greatly helped restore degraded lands in Himachal Pradesh,” noted Sharma, citing a case where the state forest department along with the panchayat-level watershed development group planted trees in vulnerable areas, which have resulted in large positive changes over the past two to three decades.
According to Dharumarajan, reducing the severity of degradation/desertification can be achieved by establishing a “proper land use policy, protection of prime agricultural lands and regular monitoring of highly vulnerable areas.”
Kukal also stressed the importance of implementing a strict “land use change policy” at the state level. “Anybody can convert agricultural land into a settlement colony, anybody can install a factory on agricultural land,” he stated, noting that this problem was rampant in Punjab.
In order to reduce soil erosion by water, he proposed harvesting of rain/runoff water – a watershed management practice – stressing that “this needs to be a part of our policy both in urban as well as rural areas.”
“The harvested water could be stored in reservoirs at the individual or community level or used for recharging the groundwater depending on the situation. Every household needs to be sensitised for rooftop rainwater harvesting. The best example of this is Junagarh area of Gujarat, where even the small houses have rainwater harvesting reservoirs, the water of which is used for all household chores including drinking purposes,” he elaborates.
The period of time required to reclaim degraded lands can be lengthy. “If restoration work is scientifically initiated and properly executed, it will take approximately 25-30 years for a visible restoration. But in some areas such as housing colonies may not be possible to restore within such time limits,” said Sharma.
“This Atlas was prepared using visual image interpretation that may vary from eye to eye,” said Sharma. “Therefore, there is some inconsistency in mapping and identification in terms of intensity.”
Also, Dharumarajan points out that the Atlas “only helps for state-level planning.” To prepare a degradation combating plan at the district or village-level, he says, we need to map land degradation at a finer scale.
Around 78 vulnerable districts were selected for detailed mapping at a scale of 1: 50,000, which Dharumarajan says is better for preparing combating plans aimed at afforestation and conserving soil and water. These districts have already been mapped. Semiautomatic techniques were used for mapping the districts, said Sharma. In the next step, such high-resolution mapping and analysis would be carried out for all districts in India, he adds.
This article first appeared on Mongabay.