CONTENTS
- The Earth and Its People
- Pollution and Health Risks
- Feeding a Future World
- Freshwater: Lifeblood of the Planet
- Oceans in Decline
- Forests: The Earth's Lungs
- Endangered Biodiversity
- Toward a Livable Future
HIGHLIGHTS
- Can development be sustained?
- Scientists point to environmental distress syndrome
- Cities grow ever larger
- Global temperatures rising
- Are we setting the stage for our own extinction?
- World population must stabilize
Population Reports is published by the Population Information Program, Center for Communication Programs, The Johns Hopkins School of Public Health, 111 Market Place, Suite 310, Baltimore, Maryland 21202-4012, USA
Fall 2000
Series M, Number 15
Special Topics
Environmental Problems of Food-Deficit Countries
In many low-income food-deficit countries the situation is worsening. Food production capacities are deteriorating (75). These countries face a number of serious constraints to achieving food security:
Limited arable land. Most fertile land already is under cultivation. Most uncultivated land is marginal, with poor soils and either too little rainfall or too much. Without massive technological improvements or substantial investments from external sources, increases in food production in low-income food-deficit countries will soon have to come from existing agricultural land—thus putting ever more pressure on its productive capacity (49, 73).
 Susanne Riveles, Lutheran World Relief |
| In Burkina Faso, as elsewhere in Africa, villagers often have little choice but to farm marginal land. In many developing countries pressures on arable land, freshwater supplies, and other resources have been rising because of population growth. |
Shrinking family farms. In most developing countries, family farms are divided into smaller and smaller parcels for each new, larger generation of heirs. Rapid population growth has shrunk the average family farm by half over the past four decades. In 57 developing countries surveyed by FAO in the early 1990s, over half of all farms were less than one hectare in size, not enough to feed the average rural family with four to six children. In India three-fifths of all farms are less than one hectare in size (73, 192). Worldwide, an estimated 420 million people live in countries that have less than .07 hectares of cultivated land per person (59).
 Gene Thiemann, Lutheran World Relief |
| In Bangladesh family farms are being divided into ever smaller parcels for each new generation of heirs. In developing countries as a whole, the average family farm is half the size of 40 years ago. |
Land degradation. Population pressures on arable land contribute to the land's degradation, as more and more marginal land is brought into cultivation to feed more and more people (23, 49). Land degradation claims 5 million to 7 million hectares of farmland each year (73). When soils are overworked, wind and water erode them faster. Soils also can become poisoned from improper irrigation techniques and from improper use of agricultural chemicals. Moreover, in most developing countries vast amounts of agricultural land are being lost as cities expand (see sidebar, Cities at the Forefront).
Nearly 2 billion hectares of crop and grazing land are suffering from moderate to severe soil degradation—an area about the size of Canada and the US combined (14, 52, 73). In some places fertile topsoil is being depleted 300 times faster than nature can replenish it (126). In Kazakhstan, for instance, nearly half of the cropland will be lost by 2025, according to the country's Institute of Soil Management (23).
Irrigation problems. Badly planned and poorly built irrigation systems have reduced yields on one-half of all irrigated land, according to a 1995 estimate by FAO (73). Irrigation is key to agricultural production. Although only 17% of all cropland is under irrigation, irrigated croplands produce one-third of the world's food supply (178).
Roughly 70% of all water withdrawn for human use goes to irrigate crops. Yet less than half of all water withdrawn for irrigation reaches the crops. Most soaks into unlined canals, leaks out of pipes, or evaporates on its way to the fields (186). Although some of the water "lost" in inefficient irrigation systems returns to streams or aquifers, where it can be tapped again, water quality invariably is degraded by pesticides, fertilizers, and salts that run off the land (104).
 I. Spanventa/FAO |
| In Egypt workers dredge an irrigation canal. About 70% of all water withdrawn for human use goes to irrigate crops. Yet less than half of all water withdrawn for irrigation reaches the crops. |
Salt buildup in soil has severely damaged 30 million hectares of the world's 255 million hectares of irrigated land, FAO estimates. A combination of salinization and waterlogging affects another 80 million hectares (73, 186). The world's irrigated croplands may actually be shrinking at a time when they should be expanding to meet demand (23).
