The terms desertification refers to degradation of land in arid, semi-arid and sub-humid areas resulting from various factors, including climatic variations and human activities. It does not imply loss of land to desert or through sand-dune movement.
Land degradation occurs everywhere, but is known as desertification when it occurs in the dryland ecosystems, i.e. land areas where the mean annual precipitation is less than two thirds of potential evapotranspiration (PET = potential evaporation from soil plus transpiration by plants), excluding polar regions and some high mountain areas which meet this criterion but have completely different ecological characteristics.
They cover over one-third of the world‘s land area and are extremely vulnerable to overexploitation and inappropriate land use. Poverty, political instability, deforestation, overgrazing and improper irrigation practices can all play a complex role in undermining the productivity of the land. The drivers can be climatic as well, such as low soil moisture, changing rainfall patterns and high evaporation.
However, majority of them are human-related, and include poverty, technology, global and local market trends and socio-political dynamics. It is vital to mention that poverty is both a cause and consequence of land degradation.
Other major side-effects of include: diminished food production, soil infertility and a decreased natural resilience of the land; increase in downstream flooding, reduction in water quality, sedimentation in rivers and lakes, and silting of reservoirs and navigation channels; aggravated health problems due to wind-blown dust, including eye infections, respiratory illnesses, allergies, and mental stress; loss of livelihoods forcing affected people to migrate.
GLOBAL DESERTIFICATION VULNERABILITY MAP, 1998
Drylands take up 41.3 per cent of the land surface, out of which 6.6 per cent consists of deserts and 34.6 per cent is drylands (un.org). They are major contributors to the world’s breadbasket, considering that one in every three crops under cultivation today has its origins in the drylands.
They are valuable indigenous food vaults as the wild ancestors and relatives of these plants still grow there. They support 50 per cent of the world’s livestock, are wildlife habitats and account for nearly half of all cultivated systems. The affected people include many of the world’s poorest, most marginalized and politically weak citizens.The fine line between drylands and deserts once crossed cannot be reversed. Some little-known facts about drylands:-
Value of Drylands for Livelihoods
- 5 billion people live in the world’s deserts and drylands.
- 90 per cent of this population is in developing countries.
- 50 per cent of world’s livestock is supported by rangelands.
- 46 per cent of global carbon is stored in drylands.
- 44 per cent of all cultivated land is in drylands.
- 30 per cent of all cultivated plants came from drylands.
- They harbour some of the world’s most valuable and rarest biodiversity.
- 24 per cent of the land, globally, is degrading.
- 20-25 per cent of degrading land is rangeland.
- 20 per cent of degrading land is cropland.
- 5 billion people in the world depend on degrading land.
Desertification and Land Degradation in India
The latest Atlas of the Space Applications Centre (SAC, ISRO, published in 2016) reveals that 96.40 million hectare area (mha) of the country is undergoing land degradation i.e., 29.32 per cent of the Total Geographic Area (TGA) of the country during 2011-13, while during 2003-05 it was 94.53 mha (28.76 per cent of the TGA).
Around 24% of desertification/land degradation (out of total TGA) is contributed by the states of – Rajasthan, Maharashtra, Gujarat, Jammu & Kashmir, Karnataka, Jharkhand, Odisha, Madhya Pradesh and Telangana in descending order.
All other remaining states contribute less than 1 per cent (each).
But if seen from a different angle, states such as Jharkhand, Rajasthan, Delhi, Gujarat and Goa show more than 50 per cent area under desertification/land degradation, whereas in Kerala, Assam, Mizoram, Haryana, Bihar, Uttar Pradesh, Punjab and Arunachal Pradesh, it is less than 10 per cent.
DESERTIFICATION / LAND DEGRADATION STATUS MAP OF INDIA – 2011-2013
In spite of the problems at present, drylands have a great potential for development, only if handled with wise management at the global, national and local levels. A land left impoverished, will sooner or later, impoverish its inhabitants and vice versa. Sustainable land management practices can equip land users to respond to changing market demand with adapted and traditional technologies not only to generate income, but also to improve livelihoods and protect ecosystems.
These are the main thoughts that went into declaring 2010-2020 as the United Nations Decade for Deserts and the Fight Against Desertification. Infact, these trends can be reversed. To preserve soil productivity, sustainable long-term practices that combine both traditional as well as modern technology need to be applied. Another measure is to decrease the dependence on these lands by creating jobs in other sectors, improve land management, reforestation, controlling erosion, using non-wood sources of energy, zero-tillage farming etc.
The World Day to Combat Desertification and Droughtis observed every year on the 17th of June to create public awareness on the issue. This year, the day is being celebrated at Ouagadougou, the capital of Burkina Faso.
The theme for 2017 is “Land degradation and migration”. It examines the important link between land degradation and migration. Environmental degradation, food insecurity and poverty are causes of national and international migration. There is a need to look at ways by which local communities attempt to solve the present multi-fold development challenges through sustainable land management practices. The aim of this day is to celebrate land’s important role in producing food and generating local employment, as well as to show how sensible human involvement can help in adding sustainability, stability and security of drylands that are required for a strong future, that is why the slogan for the year is “Our land. Our home. Our Future.”