Land is an essential natural resource, both for the survival and prosperity of humanity, and for the maintenance of all terrestrial ecosystems. Over millennia, people have become progressively more expert in exploiting land resources for their own ends. The limits on these resources are finite while human demands on them are not. Increased demand, or pressure on land resources, shows up as declining crop production, degradation of land quality and quantity, and competition for land. Attention should now be focused on the role of humankind as stewards rather than exploiters, charged with the responsibility of safeguarding the rights of unborn generations and of conserving land as the basis of the global ecosystem.
Land is not regarded simply in terms of soils and surface topography, but encompasses such features as underlying superficial deposits, climate and water resources, and also the plant and animal communities which have developed as a result of the interaction of these physical conditions. The results of human activities, reflected by changes in vegetative cover or by structures, are also regarded as features of the land. Changing one of the factors, such as land use, has potential impacts on other factors, such as flora and fauna, soils, surface water distribution and climate. Changes in these factors can be readily explained by ecosystem dynamics and the importance of their relationships in planning and management of land resources has become increasingly evident.
Land and Land Resources refer to a delineable area of the earth's terrestrial surface, encompassing all attributes of the biosphere immediately above or below this surface, including those of the near-surface climate, the soil and terrain forms, the surface hydrology (including shallow lakes, rivers, marshes and swamps), the near-surface sedimentary layers and associated groundwater and geohydrological reserve, the plant and animal populations, the human settlement pattern and physical results of past and present human activity (terracing, water storage or drainage structures, roads, buildings, etc.) (FAO/UNEP, 1997).
Land Use is characterized by the arrangements, activities and inputs by people to produce, change or maintain a certain land cover type. (Di Gregorio and Jansen, 1998). Land use defined in this way establishes a direct link between land cover and the actions of people in their environment.
Land Cover is the observed (bio)physical cover on the earth's surface (Di Gregorio and Jansen, 1998)
The basic functions of land in supporting human and other terrestrial ecosystems can be summarized as follows:
In the terminology of environmental economics, land can be regarded as a stock renewable resource. Land resources do not easily fit into the categories of renewable or non-renewable. In general, they are slowly renewable; however, their rate of degradation far exceeds their natural rate of regeneration. In practical terms, this means that land that is lost to degradation is not naturally replaced within a human time frame, resulting in a loss of opportunities for the next generation.
The potential production of arable land and its susceptibility to degradation are dependent on the management strategies employed and on inherent soil and other characteristics. In agriculture-dependant societies this combination of factors determines potentially the population that can be supported and the standard of living. When population increases in a given area, the increased demand on production can induce stress and consequent degradation of the land resource. If no other source of income can be tapped (e.g. by migration to urban areas) people's standards of living decrease. However, if improved management strategies (including technologies) are available, either the standard of living may rise or more people can be supported at the same standard of living without deterioration of the natural resource base. It follows that an ample supply of land of suitable quality and appropriate production technologies are essential if the increasing demands of a growing population are to be met.
Currently, land resources are clearly under stress; 16 percent of arable land is degraded and the percentage is increasing (FAO, 1997). Traditional systems of land management are either breaking down or are no longer appropriate, and the management and technology needed to replace them is not always available. The primary reason for this situation is the increasing demands placed on land by the unprecedented rate of population growth and the effects it induces. Externalities related to global change are also becoming a constraint to sustainable land management.
Notwithstanding the role of technology in increasing the number of people that can be supported by the terrestrial biosphere, there are finite limits to the supply of land resources. FAO estimates that a gross area of approximately 2.5 thousand million ha of land in the developing world2 has some potential for rainfed agriculture, although two-thirds of the land are rated as having significant constraints due to topography or soil conditions, while not all of this land is available for agricultural production (Alexandratos, 1995). However, land is not evenly distributed either between countries or within countries, and the difference in access to land relative to population need is more significant than global totals. Based on an assessment of the potential production from available land, and projected population growth in 117 countries in the developing world, FAO concluded that by the year 2000, 64 countries (55 percent) would not be able to support their populations from land resources alone using production systems based on low inputs (FAO, 1982).
Land is becoming more and more scarce as a resource, and this is particularly true of land available for primary production of biomass or for conservation related purposes. Competition for land among different uses is becoming acute and conflicts related to this competition more frequent and more complex. This competition is often most apparent on the peri-urban fringe, where the continuing pressures of urban expansion compete with agricultural enterprises, and with recreational demands. Such situations frequently lead to rapid increases in the economic value of land, and land tenure becomes an important political issue.
Many factors associated with global change directly or indirectly influence how land is used. These include biophysical influences, such as changes in climate or natural or human-induced disasters, as well as socio-economic aspects such as trade liberalization, the globalization of markets, decentralization of decision making, privatization, and the widening gap between the "haves" and the "have-nots".
Although the rate at which population is increasing has slowed since 1980, the increase in actual numbers is currently higher than at any time in the world's history. Additions will average 97 million per year until the end of the century and 90 million per year until AD 2025. Ninety-five percent of this increase is expected to take place in developing countries. Present figures indicate that by the year 2050 Africa's population will be three and a half times its present level, and by the year 2150, almost five times.
The previous hundred years has seen great advances in the technology of production, such as the development of more productive crop varieties and the extension of irrigation and fertilizer use. Nevertheless, it is becoming more difficult for technological progress to keep up with the rising demands generated by population growth. This is partly a result of the extension of cropping to more marginal areas where physical factors limit potential productivity and the risks of failure are higher. The success of technology in meeting these demands has been geographically uneven, being most successful in areas of low recent population growth, such as Europe and North America, meeting with varied success in Asia and Latin America, and generally being least successful in sub-Saharan Africa, where food production per caput has actually declined by almost 20 percent since 1960.
Growth in total population over the past 50 years has been matched by a relative increase in the urban population at the expense of the rural population (Figure 1). The impact of this trend is two-fold. On the one hand, movement of people to the cities may reduce the absolute pressure on land for agriculture while stimulating the market for producers. On the other hand, production of primary products such as food, fibre and fuel must be produced from a diminishing land area by a diminishing relative population, while urban expansion reduces the total land available for agriculture. A further factor is the disproportionate migration of economically active males to the towns, leaving women, children and the aged to shoulder the burdens of agriculture. The situation is frequently exacerbated by government policies of urban bias, such as cheap food prices which favour the urban dwellers and their employers, but often penalize the food producers, who are commonly a less organized and less vociferous political constituency. Urbanization due to population growth and migration effects has also promoted a growth in per caput consumerism which has further increased the demands on land resources.
TRENDS IN RURAL AND URBAN POPULATION
Source: FAO, 1982
The symptoms of the problem of pressure on land resources are manifested both in terms of impacts on people, and in terms of deterioration in the condition of land or impacts on other natural resources (Figure 2).
The deterioration in land condition may be reflected by an impaired ability to carry out any functions of the land listed above, some of which, such as reduced capacity to produce biomass, also, in turn, affect population support or quality of life.
SYMPTOMS OF THE PROBLEM OF PRESSURE ON LAND AND RESOURCES
Many of the above factors are interrelated. Figure 3 presents the relationship between cause, problem and symptoms.
CAUSE-PROBLEMS - SYMPTOM RELATIONSHIP
The problem of land resources under stress has physical, social and political causes. At the national level, short-term political gains have often been made at the expense of long-term environmental damage. Decision-makers often face inordinately difficult decisions when trying to increase production to alleviate poverty and feed people and at the same time conserve resources to stave off environmental degradation. Often the decision-makers forfeit long-term sustainability for immediate needs. This also holds true for the subsistence level land users who have little choice but to seek immediate benefits for survival. Technology alone cannot be viewed as an answer. Frequently the technologies to manage such areas in a sustainable way are simply not available, or the land users do not have access to them due to lack of information or resources. However, a key factor is the role of human institutions and land use policies that must be adapted to face the challenge posed by these rapidly changing conditions.
The essential challenge is to address the pressure on land in a way which does not cause further deterioration in land resources or impair their essential functions. As the foregoing statistics indicate, this will be an extremely difficult task. The immediate priority is to break out of the downward spiral, in which resource-limited farmers are obliged, by shortage of land resources, to degrade these limited resources even further by inadequate land husbandry in order to satisfy immediate subsistence needs. This scenario is shown in Figure 4.
THE SPIRAL: LAND RESOURCES AND PEOPLE'S ACTIVITIES
Given that land resources management has a production and a conservation component, an obvious task is to ensure that the rate of production increases in a sustainable way. Perhaps a less obvious, but equally important, aspect of land resources management is the ability of land users and other decision-makers to take informed decisions regarding the land resources. As long as rural populations remain significant and vulnerable, there is little opportunity to enhance social capital (education, institutional and social networks) which would lead to enhanced decision making.
As shown in the simplified second scenario in Figure 4, a key to breaking the present downward spiral is to improve land users' capacity to take informed decisions. One aspect of this it to improve access to information and technology and to enhance the capacity to use them. In one sense this is the mechanism used in conjunction with the green revolution, which has been extremely successful (especially in Asian countries) in improving yields and even building surpluses. However, the green revolution technologies have not proven to be sustainable, neither in yield production nor conservation of the natural resources.
Information and technology and the capacity to use them are essential to informed and more conscious decision making. However, if individuals or institutions are not empowered to make decisions then sustainable land management cannot be the outcome. Establishing land-use policies that enable informed decisions to be made about land resources is therefore the critical factor because to be enabling policies must be built on stakeholder or land user involvement.
There is no universal technological fix for the challenge of meeting human needs while protecting the terrestrial biosphere. Land varies greatly in its productive potential, constraints and responses to management, even within areas as small as an individual farm. The specific goals of groups of land users also differ, as well as the technology and physical and financial resources at their disposal. The wide variations in land resources and socio-economic conditions necessitate an integrated planning approach applied with great flexibility to address particular questions and propose specific solutions.
Alexandratos, N. (ed). 1995. World Agriculture: Towards 2010. An FAO Study. Rome: FAO, & Chichester, UK: John Wiley.
Di Gregorio, A. and Jansen, L.J.M. 1998.Land Cover Classification System (LCCS): Classification Concepts and User Manual. For software version 1.0. GCP/RAF/287/ITA Africover - East Africa Project in cooperation with AGLS and SDRN. Nairobi, Rome.
FAO. 1982. Potential Population Supporting Capacities of Lands in the Developing World. Technical report of Project INT/75/P13, based on the work of G.M. Higgins, A.H. Kassam, L. Naiken, G. Fischer, and M.M. Shah. FAO/IIASA/UNFPA, Rome.
FAO/UNEP. 1997. Negotiating a Sustainable Future for Land. Structural and Institutional Guidelines for Land Resources Management in the 21st Century. FAO/UNEP, Rome.
Di Gregorio, A. and Jansen, L.J.M. 1998. A New Concept For A Land Cover Classification System. The Land 2(1): 55-65.
FAO. 1996. FAO Yearbook 49: Production. Rome.
FAO. 1999. Terminology for Integrated Resources Planning and Management. FAO, Rome. (in press)
FAO/UNEP. 1996. Our Land Our Future. A New Approach to Land Use Planning and Management. FAO/UNEP, Rome.
UNCED. 1993. Agenda 21: Programme of Action for Sustainable Development. United Nations, New York.
2 Available data excluding China and the countries of the former Soviet Union.