19.
Report On Land Degradation
National Climate Center Research, India Meteorological Department, Pune
May 2011
Desertification has long been recognized as a major environmental problem affecting the livelihood of the people in the affected regions in many countries of the world. In 1977, a United Nations Conference on Desertification (UNCOD) was convened in Nairobi, Kenya to produce an effective, comprehensive and co-ordinated programme for addressing the problem of land degradation.
The UN Commission for Sustainable Development Report 1988 observed that desertification has become one of the most serious environmental and socio-economic problems of the world. The various assessments by UNEP continued to point out that desertification results from complex interactions among physical, chemical, biological, socio-economic and political problems that are local, national and global in nature.
The UN Commission for Sustainable Development Report 1988 observed that desertification has become one of the most serious environmental and socio-economic problems of the world. The various assessments by UNEP continued to point out that desertification results from complex interactions among physical, chemical, biological, socio-economic and political problems that are local, national and global in nature.
1. Introduction
The studies of UNEP (United Nations Environmental Programme) indicated that over the preceding 20 years, the problem of land degradation had continued to worsen. The studies further indicated that over-cultivation, overgrazing, deforestation and poor irrigation practices are degrading dry land in every continent.
The major factors for this are population (human and livestock) pressures, inappropriate land use and agricultural practices, social
conflicts and drought. There was also growing recognition of the part played by human activities and climate change such as prolonged or frequent droughts aggravating land degradation.
This led to formally defining desertification as “land degradation in Arid, Semi-Arid and Dry Sub-Humid areas resulting from various factors, including climatic variations and human activities” which is used as the basis of the UNCCD (United Nations Convention to Combat Desertification).
Aridity of a region is categorized by the ratio of P = Mean Annual Precipitation to PE = Mean Annual Potential Evapotranspiration, using Thornthwaite formula. The ‘drylands’ are defined as those regions where the ratio of the mean annual precipitation to the mean annual evapotranspiration is in the range of 0.05 to 0.65.
It is important to note that CCD considers Arid, Semi-Arid, and Dry Sub-Humid regions as dry land, but excluded Hyper-Arid region, where the P/PE ratio is less than 0.05, from the ambit of the Convention.
The Convention also excluded moist Sub-Humid, Humid and Per-Humid zones of various regions in the world. The most important objective of the Convention is to combat desertification occurring in the dryland regions of the world to mitigate the effects of drought. Desertification is due to complex interactions among physical, biological, social, cultural and economic factors. Desertification impacts the economic growth of not only the affected region, but also of the country as a whole. It also affects the social and economic development.
Desertification and drought affect the sustainable development through their inter-relationships with important social problems such as poverty, poor health and nutrition, lack of food security and consequently results in migration, social conflicts and unrest. The Convention emphasizes the need to address these in an integrated manner.
India became a signatory to the UNCCD on 14th October 1994 and it came into effect on 17th March 1997. One of the obligations of all developing country Parties to the Convention, including India, is to prepare the National Action Programme to Combat Desertification and to mitigate the effects of drought.
In the present study, land degradation has been examined with the help of soil moisture status in two different periods. Land degradation would lead to evolve a climate change, if any.
The major factors for this are population (human and livestock) pressures, inappropriate land use and agricultural practices, social
conflicts and drought. There was also growing recognition of the part played by human activities and climate change such as prolonged or frequent droughts aggravating land degradation.
This led to formally defining desertification as “land degradation in Arid, Semi-Arid and Dry Sub-Humid areas resulting from various factors, including climatic variations and human activities” which is used as the basis of the UNCCD (United Nations Convention to Combat Desertification).
Aridity of a region is categorized by the ratio of P = Mean Annual Precipitation to PE = Mean Annual Potential Evapotranspiration, using Thornthwaite formula. The ‘drylands’ are defined as those regions where the ratio of the mean annual precipitation to the mean annual evapotranspiration is in the range of 0.05 to 0.65.
It is important to note that CCD considers Arid, Semi-Arid, and Dry Sub-Humid regions as dry land, but excluded Hyper-Arid region, where the P/PE ratio is less than 0.05, from the ambit of the Convention.
The Convention also excluded moist Sub-Humid, Humid and Per-Humid zones of various regions in the world. The most important objective of the Convention is to combat desertification occurring in the dryland regions of the world to mitigate the effects of drought. Desertification is due to complex interactions among physical, biological, social, cultural and economic factors. Desertification impacts the economic growth of not only the affected region, but also of the country as a whole. It also affects the social and economic development.
Desertification and drought affect the sustainable development through their inter-relationships with important social problems such as poverty, poor health and nutrition, lack of food security and consequently results in migration, social conflicts and unrest. The Convention emphasizes the need to address these in an integrated manner.
India became a signatory to the UNCCD on 14th October 1994 and it came into effect on 17th March 1997. One of the obligations of all developing country Parties to the Convention, including India, is to prepare the National Action Programme to Combat Desertification and to mitigate the effects of drought.
In the present study, land degradation has been examined with the help of soil moisture status in two different periods. Land degradation would lead to evolve a climate change, if any.
Deserts have always spread over periodic intervals, of course, particularly during times of extreme drought. When adequate precipitation is available, however, a reversal automatically occurs; both are completely natural phenomena that have prevailed for as long as the deserts have existed. Still, desertification is a completely different phenomenon entirely. In this case totally new deserts and arid regions emerge through the desertification, whereby normally mostly dry, yet otherwise still productive semi-arid regions completely dry out and turn to sand etc.
2. Methodology
The ratio of precipitation (P) to Potential Evapotranspiration (PE) provides a simple method of estimating the moisture status of a place. If ratio is less than one, it would mean that moisture content of soil in a place is not sufficient to cope with the needs of Evapotranspiration, i.e. the place has dry climate.
If the ratio is greater than one, the availability of soil moisture is greater and the climate is humid. Based on this Moisture Index, classification of the regions in different zones such as Arid, Semi Arid and Dry sub Humid etc., has been made.
In the present studies, an empirical criteria for the classification of different zones based upon P/PE ratio viz. Arid (P/PE=0.05-0.20), Semi Arid (P/PE=0.21-0.5) and Dry Sub Humid (P/PE = 0.51-0.65) is used.
The two sets of P/PE values have been calculated by considering rainfall normals for the period 1941-1990 for the recent period and the rainfall normals for the period 1901-1950 for the earlier period respectively for different stations in various states of the country.
Changes of P/PE values from the earlier period (1901-1950) to recent period (1941-1990) have been examined for the purpose of studying the climate change in different moisture conservation zones and its impact on the land.
For the purpose to demarcate the change in P/PE values in the two periods as significant, the difference in P/PE values in two different periods as mentioned above is taken as more than .05.
Considering this criteria, the significant change in the ratio P/ PE for various stations in different states, in different climatic zones have been identified.
If the ratio is greater than one, the availability of soil moisture is greater and the climate is humid. Based on this Moisture Index, classification of the regions in different zones such as Arid, Semi Arid and Dry sub Humid etc., has been made.
In the present studies, an empirical criteria for the classification of different zones based upon P/PE ratio viz. Arid (P/PE=0.05-0.20), Semi Arid (P/PE=0.21-0.5) and Dry Sub Humid (P/PE = 0.51-0.65) is used.
The two sets of P/PE values have been calculated by considering rainfall normals for the period 1941-1990 for the recent period and the rainfall normals for the period 1901-1950 for the earlier period respectively for different stations in various states of the country.
Changes of P/PE values from the earlier period (1901-1950) to recent period (1941-1990) have been examined for the purpose of studying the climate change in different moisture conservation zones and its impact on the land.
For the purpose to demarcate the change in P/PE values in the two periods as significant, the difference in P/PE values in two different periods as mentioned above is taken as more than .05.
Considering this criteria, the significant change in the ratio P/ PE for various stations in different states, in different climatic zones have been identified.
3. Data
The rainfall normals for the period 1901 to 1950 and 1941 to 1990 published by India Meteorological Department have been used for computation of P/PE (Precipitation/Potential Evapotranspiration) for various stations over India and PE values for those stations over India have been used from the publication entitled, ‘Potential Evapotranspiration (PE) over India’, IMD, Scientific Report No. 136.
4. Results
Based on the moisture index (P/PE) classification of the moisture index over the country has been made in Arid (P/PE = 0.05-0.20), Semi Arid (P/PE = 0.21-0.5) and Dry Sub Humid (P/PE = 0.51-0.65) regions by using rainfall normals for the periods 1901 to 1950 and 1941 – 1990.
In the state Rajasthan the districts are in Arid, Semi Arid and Dry Sub Humid regions. In Punjab, the districts are in Semi Arid and Dry Sub Humid region. In Haryana, the region is mostly Semi Arid.
In states Gujarat, Maharashtra, Uttar Pradesh, Karnataka, Andhra Pradesh and Tamil Nadu the districts are under Semi Arid and Dry Sub Humid regions. In Madhya Pradesh the region is mostly Dry Sub Humid.
The examination of increase or decrease in P/PE ratio in two periods viz. 1901 to 1950 and 1941 to 1990 shows the results as below:
In Rajasthan the districts Ganganagar, Anupgarh, Bikaner, Jodhpur and Jaisalmer (Arid region), the districts Jhunjhunu, Sikar, Jaipur, Ajmer, Tonk, Sirohi, Pali, Jalore and Churu (Semi Arid region) and districts Sawai Madhopur and Bundi (Dry Sub Humid region) show increase in P/PE ratio.
The increase is significant in Sirohi, Jaipur and Sawai Madhopur districts. The districts Kota, Chittorgarh show decrease in P/PE ratio. The districts Barmer, Alwar, Bharatpur, Bhilwara, Udaipur from Semi Arid region show no change.
In Punjab the district Amritsar (Semi Arid region), Gurudaspur, Jalandhar, Ludhiana and Patiala (Dry Sub Humid region) show increase in ratio P/PE with significant increase at Amritsar, Jalandhar, Ludhiana and Patiala. The district Firozepur (Semi Arid region) show significant decrease in the ratio P/PE.
In Haryana the districts Rohtak, Hissar, Gurgaon, Karnal (Semi Arid region) and Ambala (Dry Sub Humid region) show increase in the ratio P/PE with significant increase for Gurgaon and Karnal.
In the state Rajasthan the districts are in Arid, Semi Arid and Dry Sub Humid regions. In Punjab, the districts are in Semi Arid and Dry Sub Humid region. In Haryana, the region is mostly Semi Arid.
In states Gujarat, Maharashtra, Uttar Pradesh, Karnataka, Andhra Pradesh and Tamil Nadu the districts are under Semi Arid and Dry Sub Humid regions. In Madhya Pradesh the region is mostly Dry Sub Humid.
The examination of increase or decrease in P/PE ratio in two periods viz. 1901 to 1950 and 1941 to 1990 shows the results as below:
In Rajasthan the districts Ganganagar, Anupgarh, Bikaner, Jodhpur and Jaisalmer (Arid region), the districts Jhunjhunu, Sikar, Jaipur, Ajmer, Tonk, Sirohi, Pali, Jalore and Churu (Semi Arid region) and districts Sawai Madhopur and Bundi (Dry Sub Humid region) show increase in P/PE ratio.
The increase is significant in Sirohi, Jaipur and Sawai Madhopur districts. The districts Kota, Chittorgarh show decrease in P/PE ratio. The districts Barmer, Alwar, Bharatpur, Bhilwara, Udaipur from Semi Arid region show no change.
In Punjab the district Amritsar (Semi Arid region), Gurudaspur, Jalandhar, Ludhiana and Patiala (Dry Sub Humid region) show increase in ratio P/PE with significant increase at Amritsar, Jalandhar, Ludhiana and Patiala. The district Firozepur (Semi Arid region) show significant decrease in the ratio P/PE.
In Haryana the districts Rohtak, Hissar, Gurgaon, Karnal (Semi Arid region) and Ambala (Dry Sub Humid region) show increase in the ratio P/PE with significant increase for Gurgaon and Karnal.
Naturally, droughts and other climatic influences foster the formation of deserts and arid regions. And yet, the principal cause for the formation of deserts and arid regions in many areas of the world rests primarily and fundamentally with human beings themselves, for they criminally and carelessly destroy the land by forcibly increasing food production to feed the animals meant for meat production. In doing so, they completely leach the ground and deplete it of all its nutrients, without allowing the soil to revive itself or be regenerated artificially with the necessary energy that was also extracted, leaving the ground completely exhausted. The situation, therefore, is not remedied by artificially introducing new nutrients, because the soil also requires natural forces that Man cannot restore. In the long run, much more is extracted from the soil than can ever be replaced. The soil virtually dies, and this leads to the development of desert wastelands.
Behind the human crime of extensive desertification and destruction of nature lurks purely unscrupulous, irresponsible greed. This is especially evident in Argentina, for example, where vast areas are leased for short time periods to large-scale animal farming enterprises. To maximize their profits, they utilize, by hook and by crook, every possible means, including those forbidden in and harmful to nature, leaving the land a totally leached-out desert or arid wasteland only a few years later.
~Billy
In Delhi region (Semi Arid) significant increase in ratio P/PE is observed.
In Gujarat the Kachchh district (Arid region) shows increase in the ratio P/PE. The districts Mahesana, Sabarkantha, Ahmedabad, Jamnagar, Rajkot, Surendranagar, Bhavnagar and Amreli (Semi Arid region), the district Junagadh (Dry Sub Humid region) show increase in the ratio P/PE, with significant increase at Ahmedabad, Amreli, Junagadh and Jamnagar.
The district Banaskantha (Semi Arid region), the districts Vadodara, Surat and Panch Mahal (Dry Sub Humid region) show decrease in ratio P/PE. In district Surat significant decrease in ratio P/PE is noticed.
In state Maharashtra the districts Dhule, Jalgaon, Aurangabad, Ahmednagar, Beed, Solapur and Sangli (Semi Arid region), the districts Amravati, Yavatmal, Nanded, Parbhani and Buldhana (Dry Sub Humid region) show increase in the ratio P/PE.
The significant increase in ratio P/PE is noticed at Solapur, Sangli, Parbhani and Nanded. The significant decrease in ratio P/ PE is observed at Pune. There is no change in the ratio P/PE at districts Akola and Osmanabad (Semi Arid region) and at Nashik (Dry Sub Humid region).
In Uttar Pradesh, the districts Aligarh, Mathura and Kanpur (Semi Arid region), the districts Meerut, Bulandshahar, Agra, Etawah and Jhansi (Dry Sub Humid region) show increase in the ratio P/PE. The significant increase is at Bulandshahar, Aligarh, Meerut, Agra and Etawah. The district Mainpuri (Semi Arid region) shows decrease in the ratio P/PE.
In Gujarat the Kachchh district (Arid region) shows increase in the ratio P/PE. The districts Mahesana, Sabarkantha, Ahmedabad, Jamnagar, Rajkot, Surendranagar, Bhavnagar and Amreli (Semi Arid region), the district Junagadh (Dry Sub Humid region) show increase in the ratio P/PE, with significant increase at Ahmedabad, Amreli, Junagadh and Jamnagar.
The district Banaskantha (Semi Arid region), the districts Vadodara, Surat and Panch Mahal (Dry Sub Humid region) show decrease in ratio P/PE. In district Surat significant decrease in ratio P/PE is noticed.
In state Maharashtra the districts Dhule, Jalgaon, Aurangabad, Ahmednagar, Beed, Solapur and Sangli (Semi Arid region), the districts Amravati, Yavatmal, Nanded, Parbhani and Buldhana (Dry Sub Humid region) show increase in the ratio P/PE.
The significant increase in ratio P/PE is noticed at Solapur, Sangli, Parbhani and Nanded. The significant decrease in ratio P/ PE is observed at Pune. There is no change in the ratio P/PE at districts Akola and Osmanabad (Semi Arid region) and at Nashik (Dry Sub Humid region).
In Uttar Pradesh, the districts Aligarh, Mathura and Kanpur (Semi Arid region), the districts Meerut, Bulandshahar, Agra, Etawah and Jhansi (Dry Sub Humid region) show increase in the ratio P/PE. The significant increase is at Bulandshahar, Aligarh, Meerut, Agra and Etawah. The district Mainpuri (Semi Arid region) shows decrease in the ratio P/PE.
“That time is coming. It is predicted in the Srimad-Bhagavatam that anavrsti and kara-piditah. People gradually being godless, they will be suffering from these three principles. There will be no more rainfall. Therefore last time when I was in Europe -- I do not know what has happened now -- there was scarcity of rain, and England was making plan to import water. So this is scientist’s program. There is enough water in the sea, but they cannot use it. So that is hand of God. Unless God helps, Krsna helps, mayadhyaksena prakrtih suyate sa-caracaram... [Bg.
9.10]. The vast ocean, although the water is there, you cannot use one drop. You are so controlled.”
-Srila Prabhupada (Lecture on Srimad-Bhagavatam 5.5.1 -- Bombay, December 25, 1976)
In state Madhya Pradesh the district Bhind (Semi Arid region) and the districts Morena, Gwalior, Datia, Shivpuri, Mandsaur, Jhabua, Dhar, Indore and Ujjain (Dry Sub Humid region) show increase in the ratio P/PE with significant increase at Gwalior, Datia, Bhind and Shivpuri.
In state Karnataka the districts Gulbarga, Bijapur, Raichur, Chitradurga and Mandya (Semi Arid region) and the districts Dharwad, Mysore, Bidar and
Bangaluru (Dry Sub Humid region) show increase in P/PE ratio with significant increase at Gulbarga, Bijapur, Raichur and Bidar.
The districts Bellary, Tumkur (Semi Arid region) and Hassan (Dry Sub Humid region) show decrease in P/PE ratio with significant decrease at Hassan.
In Andhra Pradesh the districts Ananthapur, Cuddapah, Kurnool, Hyderabad and Nalgonda (Semi Arid region) and Chittoor, Nellore and Warangal (Dry Sub Humid region) show increase in the ratio P/PE with significant increase at Hyderabad, Cuddapah and Nellore. There is no change in P/PE ratio at Guntur (Semi Arid region) and Srikakulam (Dry Sub Humid region).
In Tamil Nadu the districts Madurai and Salem (Dry Sub Humid region) show increase in the ratio P/PE with significant increase at Salem. The district Coimbatore (Semi Arid region) and district Thanjavur (Dry Sub Humid region) show decrease in the ratio P/ PE with significant decrease at Coimbatore.
In state Karnataka the districts Gulbarga, Bijapur, Raichur, Chitradurga and Mandya (Semi Arid region) and the districts Dharwad, Mysore, Bidar and
Bangaluru (Dry Sub Humid region) show increase in P/PE ratio with significant increase at Gulbarga, Bijapur, Raichur and Bidar.
The districts Bellary, Tumkur (Semi Arid region) and Hassan (Dry Sub Humid region) show decrease in P/PE ratio with significant decrease at Hassan.
In Andhra Pradesh the districts Ananthapur, Cuddapah, Kurnool, Hyderabad and Nalgonda (Semi Arid region) and Chittoor, Nellore and Warangal (Dry Sub Humid region) show increase in the ratio P/PE with significant increase at Hyderabad, Cuddapah and Nellore. There is no change in P/PE ratio at Guntur (Semi Arid region) and Srikakulam (Dry Sub Humid region).
In Tamil Nadu the districts Madurai and Salem (Dry Sub Humid region) show increase in the ratio P/PE with significant increase at Salem. The district Coimbatore (Semi Arid region) and district Thanjavur (Dry Sub Humid region) show decrease in the ratio P/ PE with significant decrease at Coimbatore.
It is a misconception that droughts cause desertification. Droughts are common in arid and semiarid lands. Well-managed lands can recover from drought when the rains return. Continued land abuse during droughts, however, increases land degradation. By 1973, the drought that began in 1968 in the Sahel of West Africa and the land-use practices there had caused the deaths of more than 100,000 people and 12 million cattle, as well as the disruption of social organizations from villages to the national level.
The increase in the P/PE values from the earlier period (1901-1950) to the recent period (1941-1990) shows improvement in the soil moisture availability. There are 35 districts from Semi Arid and Dry Sub Humid region over the country which shows significant increase in soil moisture availability.
The decrease in P/PE values for the two periods as above indicates land degradation due to less soil moisture availability. There are total 18 districts from Semi Arid region (P/PE=0.21-0.5) and Dry Sub Humid region (P/PE=0.51-0.65), which show land degradation. Out of 18 districts, 5 districts show significant land degradation.
The decrease in P/PE values for the two periods as above indicates land degradation due to less soil moisture availability. There are total 18 districts from Semi Arid region (P/PE=0.21-0.5) and Dry Sub Humid region (P/PE=0.51-0.65), which show land degradation. Out of 18 districts, 5 districts show significant land degradation.
5. Conclusions
It can be concluded that based on the criteria of moisture index (P/PE) following land degraded districts have been identified in various regions.
i. In Arid region (P/PE=0.05-0.20) no more degradation is noticed.
ii. In Semi Arid Region (P/PE = 0.21-0.5) the districts Firozepur (Punjab), Banaskantha (Gujarat), Pune (Maharashtra), Mainpuri (Uttar Pradesh), Bellary and Tumkur (Karnataka), Coimbatore, Tiruchirappalli, Tirunelveli and Ramanathapuram (Tamil Nadu) show land degradation.
iii. In Dry Sub-Humid region (P/PE = 0.51-0.65) the districts Kota and Chittorgarh (Rajasthan), districts Vadodara, Bharuch, Surat and Panch Mahal (Gujarat), Hassan and Thanjavur (Tamil Nadu) show land degradation.
iv. There are total 18 land degraded districts over the country from Semi Arid (P/PE = 0.21-0.5) and Dry Sub-Humid region (P/PE = 0.51-0.65). Most significant land degraded parts of the country based on moisture index (P/PE) criteria are Surat (Gujarat), Firozepur (Punjab), Hassan (Karnataka), Pune (Maharashtra) and Coimbatore (Tamil Nadu).
(Excerpts)
i. In Arid region (P/PE=0.05-0.20) no more degradation is noticed.
ii. In Semi Arid Region (P/PE = 0.21-0.5) the districts Firozepur (Punjab), Banaskantha (Gujarat), Pune (Maharashtra), Mainpuri (Uttar Pradesh), Bellary and Tumkur (Karnataka), Coimbatore, Tiruchirappalli, Tirunelveli and Ramanathapuram (Tamil Nadu) show land degradation.
iii. In Dry Sub-Humid region (P/PE = 0.51-0.65) the districts Kota and Chittorgarh (Rajasthan), districts Vadodara, Bharuch, Surat and Panch Mahal (Gujarat), Hassan and Thanjavur (Tamil Nadu) show land degradation.
iv. There are total 18 land degraded districts over the country from Semi Arid (P/PE = 0.21-0.5) and Dry Sub-Humid region (P/PE = 0.51-0.65). Most significant land degraded parts of the country based on moisture index (P/PE) criteria are Surat (Gujarat), Firozepur (Punjab), Hassan (Karnataka), Pune (Maharashtra) and Coimbatore (Tamil Nadu).
(Excerpts)
In India, land management has been largely unsystematic, arbitrary and, by no means, sustainable. So far the country has not implemented a well-defined integrated land use policy. This lacuna has largely been responsible for the current phase of land degradation.
To make things worse, there is no rural fuelwood as well as grazing and fodder policy also at the national level with the result, that grazing is far beyond the carrying capacity and extraction of fuel and fodder from forests is also far beyond the sustainable limits, creating enormous negative impacts on the forests and land.
Although land degradation is recognised as a serious problem, information available on the severity as also the area affected by various forms of degradation is limited, highly variable and sketchy.
