Approximately 40 percent of soil used for agriculture around the world is either degraded or seriously degraded – meaning, among other things, that 70 percent of the topsoil – the layer allowing plants to grow – is gone (WEF, 2012). Our soil is losing its ability to perform the services that are essential for humans to survive. Overexploitation has diminished soil’s capacity to retain water and nutrients, produce food, and absorb CO2, just to mention a few essential services.
The UN Food and Agriculture Organisation (FAO) estimates that food production must increase by 70 percent between now and 2050 if we are to feed the growing world population (FAO, 2016). However, each year we lose about 100,000 km² of cropland (approximately the size of Iceland) due to soil erosion, which is the type of soil degradation that refers to absolute soil losses in terms of topsoil and nutrients. If we continue on the same trajectory we are on, we will produce 30 percent less food over the next 20-50 years.
Soil degradation is primarily happening due to different human activities such as overgrazing of farm animals (approx. 35 percent), agricultural activities (approx. 28 percent), deforestation (approx. 30 percent), overexploitation of land to produce fuel wood (approx. 7 percent), and industrialization (approx. less than 1 percent) (University of Michigan, 2010).
The utilization of a narrow selection of crops is another serious factor threatening the nutrient quality of soil. Modern agriculture focuses on the cultivation of a few major staple crops, such as rice, maize, wheat and potato. In fact, these four edible plants provide 60 percent of the world’s dietary energy intake (FAO, 2015). Intensive cultivation of these few select crops will make it more difficult for conserving the soil and will decrease natural soil fertility.
A report from 2015 estimates that the global cost of land degradation amounts to as much as USD 10.6 trillion every year – pooling together not only the cost from lost agricultural production and diminished livelihoods, but also from the lost value of ecosystem services such as water filtration, erosion prevention, nutrient cycling and the provision of clean air (ELD Initiative, 2015).
Since humans worldwide obtain more than 99.7 percent of their food (calories) from the land and less than 0.3 percent from the oceans and aquatic ecosystems, implementing new approaches to combat the risk of soil degradation is of the outmost importance (Pimental & Burgess, 2013).
Furthermore, soil degradation creates a vicious cycle, in which less carbon is stored, accelerating the effects of global warming, and in turn further degrading land (WWF). Perhaps surprisingly, soils are the second largest active store of carbon after the oceans and more carbon is stored in soil than in the atmosphere (760 billion tonnes) and in vegetation (560 billion tonnes) combined (DG Environment, 2013). The ability of soil to act as a retainer for carbon has been weakened in recent decades and projections show that the amount of carbon released from poor soil management threatens to undermine reductions made in other sectors (DG Environment, 2013).
Further loss of productive soils would severely damage food production and food security, amplifying food-price volatility, and potentially plunging millions of people into hunger and poverty (FAO, 2016). Although natural soil can be regenerated, the rate at which this happens is very slow. For this reason, soil should be considered a non-renewable asset to be conserved with care for generations to come (Parikh & James, 2012).
Soil is being exploited and irreversibly lost and degraded. The signs and the impacts are showing more clearly and responses are required, so that the problem does not continue to be transferred to future generations.