Soil Degradation: At the Core of the Anthropocene’s Intricate Fragility

As terrestrial beings we are tied to the ground below our feet. Soil is our steady companion as we are riveted to earth by the force of gravity. From times ancient, human beings have recognised the paramountcy of soil for life on earth. In Latin, homo means “human” and humus “soil”, both deriving from the same semantic root. In the Bible, we are reminded in verse 3:19 of the Genesis that soil constitutes our point of origin and final destination: “for dust you are and to dust you will return”. A variety of cultures across space and time have considered earth as the ancestral mother of all life (Gaia in Ancient Greece or Pachamama for the Incas) or as a goddess of harvest serving as nourishing matrix (Demeter, Ceres). Eventually, we came to call the whole planet “Earth” even though most of its surface is water and its core, incandescent magma.

In fact, soil constitutes only a thin layer of the earthly crust – a fine membrane composed of clay particles, humus and sand – hosting billions of microorganisms, animals, plants and fungi that sustain food production and the existence of most species. Somewhat counterintuitively, however, land is a scarce and finite resource. Even though we can simply buy a bag of humus in the garden store, it takes centuries, if not millenniums, for the combined action of sun, rain, frost and soil organisms to decompose rocks into smaller particles, eventually forming successive layers of loose soil.

Soils as a vital component of the Anthropocene

Since the Neolithic humans have exerted an ever growing and lasting impact on their environment through sedentary agriculture and the domestication of livestock. For more than 8,000 years, human beings have been clearing forests, tilling, watering and fertilising cropland, giving rise to a new geological era, the Anthropocene.Soil degradation, biodiversity, food security and climate change are closely interdependent. 

The Enlightenment definitely placed mankind at the centre stage of the planet’s destiny, adopting a radically instrumental and utilitarian approach to the environment based on a teleological reading of historical progress. With the Industrial Revolution, the impact of mankind on the biosphere massively intensified, as the combustion of carbon fossil and the discovery of electricity led to large-scale deforestation and the uprooting of soils through the mechanisation of agriculture and mining.

However, it is only in the twentieth century that the “great leap forward” paved the way for the massive aggravation of land degradation through unprecedented levels of population growth, large-scale industrialisation, high-yield agriculture, urban sprawl and the spread of human infrastructure. The conversion of native vegetation into crop and grazing lands to satisfy a growing global demand for food generated overcutting of vegetation and overgrazing. The generalised use of chemicals, pesticides and fertilisers led to overexposure to pollutants, heavy metals, and nitrates in soils. The use of heavy machinery in agriculture contributed to soil compaction and erosion while mining activities aggravated global soil and water contamination through the dissemination of highly toxic substances such as cyanide, chrome and mercury.

Endangered Earth

Today, the Earth is in serious danger. Soil degradation – including erosion, nutrient depletion, acidification, salinisation, compaction and chemical pollution – entails devastating consequences such as loss of biodiversity, floods, climate change, famines, forced migration and conflict. Current rates of soil degradation are alarming. According to the United Nations Environment Programme (UNEP), 33% of soil is moderately to highly degraded and each year, 24 billion tonnes of fertile soil and 15 billion trees are lost. Topsoil is being degraded 10 to 40 times faster than it is being replenished by natural processes. Wetlands have been particularly hard hit, with 54% lost since 1900. Land degradation also is a crucial issue in drylands, which cover approximately 40% of the world’s terrestrial and are highly vulnerable to climate change, erosion and desertification.

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Currently, 1.5 billion people are affected by land degradation, especially rural communities, smallholder farmers, and the very poor. The loss of species and biodiversity progresses at 100 to 1,000 times the normal background rate of extinction; risks for epidemics increase with the transformation of natural ecosystems such as the melting of permafrost; floods become more frequent as the soil is no longer able to fulfill its filtering and storing function; and, eventually, famine, migration and conflict may result from desertification and the loss of arable lands. The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) estimates that 50–700 million people may migrate by 2050 because of land degradation. History is full, indeed, of warnings about civilisations such as that of Easter Island, the Greenland Norse, the Mayans and the Mycenaean Greece that have collapsed as a result of land degradation and large-scale disruption of ecosystems.

The complex fragility of the biosphere

Issues such as large-scale exploitation of land and natural resources, soil degradation, biodiversity, food security and climate change are closely interdependent and cannot be treated in isolation as the Anthropocene is characterised by complex cybernetic loops. Food production, for instance, contributes to land degradation through intensive (mono)culture and soil pollution and it accelerates climate change through the liberation of carbon into the air (it is estimated that there is three times more carbon stored in the soil than in the atmosphere). Climate change, in turn, affects food production through the degradation of soils induced by flooding, erosion and desertification. Impoverished soils, finally, further accelerate climate change because of their reduced capacity to regulate complex ecosystems and store carbon, and, ultimately, they prove unsustainable to food production.

The link between soil degradation and climate change, in particular, has started to receive increased scrutiny. Soil carbon stocks are highly vulnerable to human activities such as deforestation, tillage and unsustainable agricultural practices. It is estimated that an increase of just 1% of carbon stocks in the top meter of soils would have a higher impact than the total amount of yearly anthropogenic CO2 emissions from fossil fuel burning. Deforestation alone contributes to about 10% of all human-induced greenhouse gas emissions. The drainage of marshland and meadows for agriculture is particularly problematic as they represent the most efficient carbon store of all terrestrial ecosystems. Put simply therefore, soil protection is also climate protection.

Overcoming the agricultural taboo

As the international community is progressively growing aware of the negative impact of agriculture on the environment, soils have recently received increased attention. Less publicised than climate change or loss of biodiversity, the issue of soil degradation has been at the core of a report by the Intergovernmental Panel on Climate Change (IPCC), stressing the urgency of sustainable soil management to curb global warming and feed humanity. Already in September 2015, the UN General Assembly had adopted land degradation neutrality objective as target 15.3 of the Sustainable Development Goals (SDGs), to be achieved collectively by 2030.For too long, indeed, agriculture has been treated as a holy cow and soils as a quasi-inexhaustible resource. 

There now seems to be general agreement that halting and potentially reversing land degradation is a prerequisite for fulfilling crucial environmental objectives such as maintaining biodiversity, ensuring global food security and mitigating climate change. This has brought a readiness, it seems, to closer scrutinise the impact of agriculture, which is among the greatest contributors to global warming, responsible for 80% of land degradation and also the main driver of biodiversity loss and water stress. For too long, indeed, agriculture has been treated as a holy cow, and soils as a quasi-inexhaustible resource serving the productivist credo of the green economy.

Managing land degradation and human survival

Has Earth thus arrived at a point of rupture? The issue at stake is how to reconcile agricultural production, the imperatives of food security and the growth of high-consumption lifestyles in both developed and emerging economies with the preservation of soils and, concomitantly, the climate. It is estimated that by 2050, food production will have to increase by 40%–70% to feed the world population while today 850 million people are still facing hunger on a daily basis. Gloomy Malthusian outlooks are, however, tempered by the fact that, in the long run, population growth will inexorably slow and agricultural efficiency will continue to increase with technological innovation and transfer.

Sustainable land management is one of the key means to reverse land degradation. Undermanaged areas need to increase yields by introducing modern mechanisation, irrigation, and fertilising techniques. Overmanaged arable lands, on the contrary, need to be made less exacting on the environment through reduced tillage and fertiliser usage, crop rotations and “cover crops”, and the increase of soil organic matter content. High-tech, precision farming systems, such as sensors, GPS and subsurface drip irrigation, will allow to waste less water and better target the application of fertilisers and pesticides. Sophisticated robot farmers replacing more heavy conventional machinery will contribute to alleviate soil compactionThe agriculture of tomorrow needs to combine technological innovation with more sustainable practices rooted in traditional, organic farming. 

Technology, however, will not suffice to address land degradation. It needs to be complemented by broader land restoration measures such as agroforestry, the improvement of biomass and land cover, water conservation and the reflooding wetlands, as well as the mitigation of climate change and desertification. Avoiding further deforestation must become a top priority as the simplest way to protect soils and combat global warming is to preserve forests and let them grow back. In sum – and far from being contradictory – the agriculture of tomorrow needs to combine technological innovation with more sustainable practices rooted in traditional, organic farming.

Tackling land degradation and food security will thus require a holistic approach and concerted action on a transnational level. A host of multilateral agreements already exist, including on desertification, climate change, biodiversity and wetlands, that may serve as platforms from which to address land degradation. At the national level, policies and regulations will have to be implemented such as payments for ecosystem services, measures to curb soil pollution, improved urban planning, more efficient fire management as well as flood prevention. All of these measures must be designed with caution, taking into consideration the complex nexus between local livelihoods, land degradation, and climate change.

Seeking to explore and untangle these interlinkages, this Dossier aims to address some of the broader stakes the Anthropocene is currently facing: How irreversible is the damage that has been caused to Earth’s soils? How many people is the Earth able to feed and for how long? How will climate change depend and interact with changing patterns of soil distribution and depletion?