The Wasteland
What's the problem?
Globally nearly 2 billion hectares (ha) of land are affected by land degradation to various degrees. This means that a large proportion of the world's land surface has declined in quality and productivity as a result of human activity. The Food and Agriculture Organisation (FAO) calls this "a serious threat to food security...the livelihood systems (and ultimately the survival) of some human communities are at risk and...a massive loss of biological diversity is likely to occur." [1]
The World Resources Institute (WRI) states that nearly 40% of the world's agricultural land is seriously degraded; almost 75% of cropland in Central America, 20% in Africa, and 11% in Asia. Soil degradation has already had significant impacts on the productivity of about 16% of agricultural land. These figures "raise all kinds of red flags about the world's ability to feed itself in the future," says Ismail Serageldin, World Bank Vice President for Special Programs and Chairman of the Consultative Group on International Agricultural Research (CGIAR) [2]
The International Food Policy Research Institute (IFPRI) predicts that if land loss continues at current rates an additional 150 to 360 million hectares could go out of production by 2020. [3]
The UN estimates that more than 250 million people are already directly affected by desertification and around one billion people in more than a hundred countries are at risk from famine and malnutrition as a result of the rapid decrease in the fertile land available for growing crops for human consumption. [4]
In other words, increasing population is not the only factor that we have to consider when looking at future food production. Viable agricultural land is diminishing, so that there is less and less productive soil per person. Continuing to intensify production on already degraded lands is not a sustainable solution.
THE LIVESTOCK CONNECTION
The three main causes of land degradation are over-grazing, arable farming and deforestation (see figure 2). Overall, overgrazing is blamed for 35% of soil degradation, deforestation for 30% and agriculture for 27%. [5] All these causes are directly or indirectly related to the consumption of animal products.
Overgrazing is the most direct effect. When heavy animals trample the earth, they crush plants and compact the soil, making it harder for grasses and plants to grow. This compacted soil cannot absorb water as easily, so heavy rain courses off the surface, washing away topsoil.
This is the single largest source of soil degradation, accounting for 678.7 million ha - over a third of the total degraded drylands. It is estimated to contribute to 49% of the total degraded land area in Africa. [6] The WRI estimates that 700 million ha of rangelands have been degraded over the last 50 years because of overgrazing by livestock.
Figure 2: Main Causes of Dryland Soil Degradation by Region; Source: FAO, The State of Food and Agriculture 1996
A report commissioned by the FAO, the United States Agency for International Development (USAID) and the World Bank states that "excessive livestock grazing also causes soil compaction and erosion, decreased soil fertility and water infiltration, and a loss in organic matter content and water storage capacity." [7]
As we shall see in the next section, livestock production is also one of the main causes of deforestation, which in turn contributes to soil degradation. The FAO states that "clearing of woody vegetation is generally done to extend agricultural and pasture areas." [8] Thin layers of topsoil previously protected by a fine network of roots are extremely vulnerable when the forest cover is removed and are often simply washed away or compacted and broken down by heavy cattle.
Nutrient depletion and soil displacement combine to make arable farming the third greatest factor in land degradation. As we have seen, around 45% of the world's grain harvest is fed to livestock - making livestock production indirectly responsible for a large percentage of fertility lost through arable farming.
It is a vicious cycle in which declining soil fertility pushes people to find new land to expand the agricultural base. This often leads to deforestation, which in turn causes soil degradation. This process is the epitome of unsustainable agricultural practice.