Soils are more than carbon sinks

Soils are more than carbon sinks

Agriculture and climate change are closely linked, and soils store vast amounts of carbon. But what happens when carbon sequestration in the fields of smallholders becomes a new focus in climate and agricultural policies? The article takes a critical look at various initiatives, including “climate-smart agriculture”, a concept that is being promoted by the Food and Agriculture Organization (FAO) and other bodies as a “win-win-win” solution to increase productivity, adapt to climate change and reduce emissions.

Ein Feld in Ruanda

Agriculture accounts for one third of man-made climate change if land-use changes such as deforestation are included. If transportation, processing and packaging, refrigeration, trade and waste are also taken into consideration, estimates of the industrial food system’s responsibility for climate change can be put as high as 50 percent. In addition to carbon dioxide (CO2), other greenhouse gases have a major impact: about 50 percent of global man-made methane emissions (CH4) and 60 percent of nitrous oxide (N2O) are produced by agriculture, mainly by industrial livestock farming and fertilizers.

There are many ways to reduce these greenhouse gases while protecting ecosystems: from limits on meat production, pesticides and synthetic fertilizers, to the regionalization of economic cycles to eliminate long transportation routes and the application of agroecology. However, the measure that is garnering special attention from governments, private companies and institutions such as the World Bank at the moment is the improved sequestration of carbon in farmland.

Carbon sequestration in soils

Preventing the climate crisis will firstly require drastically reducing the use of fossil fuels and thus greenhouse gas emissions, and secondly protecting and enlarging the spaces in which greenhouse gases are stored. Soils, forests and oceans are vital “sinks” for greenhouse gases such as carbon, methane and nitrous oxide. Soils contain more carbon than all plants and the atmosphere combined.

Climate change accelerates soil respiration. As a result, greenhouse gases escape into the atmosphere more quickly, in turn accelerating global warming. In addition to the climate, it is above all the form of agriculture that determines whether greenhouse gases remain in the soil or not: Must rainforests give way to oil palm plantations? Are synthetic fertilizers or organic compost applied to fields?

Studies show that while carbon sequestration in soils or forests is important, it cannot be an alternative to massive emission reductions. Keeping oil, coal and gas – i.e. highly concentrated carbon – in the deep layers of the earth is much more effective than concentrating on the storage of surface carbon in soils or trees, as there is no guarantee that surface carbon will remain in the soil in the long term. Moreover, the scientific community disagrees on consistent and sound methods of calculating soil storage. Storage capacity varies greatly depending on the climate zone, geological conditions, soil composition, weather conditions and agricultural methods. 

Carbon in the fields – a future business model?

Carbon in fossil fuels and that in plants and soils cannot be equated in terms of their climate impact. Furthermore, the calculation methods are highly controversial. Nevertheless, in recent years there has been a boom in projects and initiatives that calculate carbon storage in soils in order to subsequently sell emission credits – i.e. pollution rights – on voluntary or state emission markets. This approach started previously in the forestry sector through the controversial REDD+ (Reducing Emissions from Deforestation and Forest Degradation) mechanism. It is now to be applied in a similar way to agriculture.

The need for more humus and carbon in the soil is therefore increasingly linked to relieving other industrial sectors of the need to do their homework, i.e. to reduce their emissions. Proponents say that carbon storage in soils is associated with lower costs than, for example, shutting down coal-fired power plants or restricting transportation. The new hype surrounding the business with carbon in fields has a variety of dimensions:

For example, Hofer, the Austrian subsidiary of the Aldi discount grocery chain, has been touting itself as “carbon-neutral” since 2016. How is that possible? The discounter has by no means switched its product range to organic or changed its concept in any fundamental way. In addition to renewable energy for its warehouses and shops, the supermarket chain instead relies mainly on purchasing offset credits – including those from projects for ostensibly “documented” carbon sequestration in soils. These come from the Austrian “Eco Region Kaindorf” initiative, which sells humus certificates and is a pioneering project in German-speaking countries in this regard. Aldi also wants to present itself as a green supermarket in other countries in a similar way.

Terra preta – biochar that is produced when biomass is heated in the absence of air – is also up and coming. It can be produced on a small scale, purchased or manufactured industrially in order to achieve better yields in agriculture and to enrich soils with carbon. However, it is unclear how long the carbon will remain there and how it will affect methane and nitrous oxide storage in the soil; some studies have even shown negative effects on greenhouse gas sequestration. Increasingly, initiatives are trying to generate offset credits through terra preta – and thus legitimize emissions elsewhere. If the boom in biochar leads to its industrial use, this would also be considered geoengineering. The big question is where to source the biomass. This is already partly leading to increasing pressure on other areas and forests and a new form of land grabbing or “green grabbing”.

Another trend is conservation agriculture, in which the lowest possible tillage is supposed to ensure that carbon is left in the soil and less diesel fuel is used for plowing. Whether the method actually contributes to climate protection, however, is controversial. Companies such as Monsanto/Bayer, Olam and Danone are touting this no-till model in order to win new markets for suitable seeds, fertilizers and pesticides. Yet more pesticides and synthetic fertilizers are by no means climate-friendly.  

The fertilizer dilemma

An enormous amount of energy is needed in the production of synthetic fertilizers. For industrial agriculture, it is responsible for up to 50 percent of the energy consumption per hectare. In contrast to cycle-oriented agriculture, it is not the farm’s own compost or manure that is incorporated into the soil. Instead, nitrogen is purchased in the form of fertilizer. This can increase yields in the short run, but over time humus degrades more quickly and nutrients and carbon become harder to store. The additional nitrogen can hardly be absorbed. Excess nitrogen is leached into the groundwater and emitted as nitrous oxide – a much more potent greenhouse gas than CO2. The problem is exacerbated by water shortages due to climate change and droughts, further reducing plant availability. More fertilizers and pesticides are therefore not the solution to the climate crisis.

Several international initiatives have emerged in recent years that link agriculture with climate protection and carbon sequestration, including Adaptation of African Agriculture (AAA), the French initiative 4 PER 1000, and perhaps the most important one: GACSA.

Global Alliance for Climate-Smart Agriculture: GACSA

The “climate-smart agriculture” (CSA) concept has been around for almost ten years now. It was developed by the UN Food and Agriculture Organization (FAO) and is anchored in numerous national policies and development strategies. It is closely linked to concepts such as the green economy, sustainable intensification, precision agriculture and conservation agriculture. It also belongs in the context of expanding private-sector participation in development cooperation, with efforts to combine development, sustainability and economic growth through public-private partnerships and the involvement of transnational agribusiness.

According to the FAO, CSA provides a threefold benefit: It “sustainably increases productivity, resilience (adaptation), reduces/removes GHGs (mitigation), and enhances achievement of national food security and development goals”. This definition could also apply to agroecology, a concept promoted by La Vía Campesina, a global smallholder organization. However, the organization rejects CSA for monopolizing the concept of agroecology while greenwashing conventional agroindustry.

Founded in 2014, the Global Climate Smart Agriculture Alliance (GACSA) defines CSA as follows: “CSA is an approach to developing the technical, policy and investment conditions to achieve sustainable agricultural development for food security under climate change.” GACSA has been accused in many quarters of being too vague and of lacking criteria to define what actually constitutes CSA. Thus, both agroecological methods such as the use of crops with deeper root systems, crop rotation or agroforestry can be part of CSA, as can new technologies for precision farming, genetically modified seeds and animal species, as well as synthetic pesticides and fertilizers. The latter are explicitly included in CSA and promoted under a green mantle.

This is justified by claims that increased productivity would ensure food security, and that intensification would curb the expansion of agricultural land and thus deforestation. In reality, however, studies (such as reports by Global Agriculture,  IPES-Food and the ETC Group) show that malnutrition is not due to a lack of productivity but to the unequal distribution of food and inputs.

In addition to intended productivity gains, the carbon sequestration in soils described above is at the heart of “climate-smart” strategies (see Box 3). This includes its monetary valuation by means of – controversial – calculation methods and the subsequent valorization of the storage capacity of soils. Through these carbon sinks, commodities are created: Carbon credits can be used to compensate for emissions elsewhere. Anyhow, this can block fundamental socio-ecological change.

There are many powerful players worldwide who have a vested interest in precisely this development. This is apparent from the list of GACSA members: GACSA has more than 230 members, including governments and NGOs as well as banks and agribusiness corporations. The list includes Danone, Syngenta, Kellogg’s and the International Fertilizer Association (IFA), while other member organizations and foundations have close links to Monsanto/Bayer, McDonalds and Cargill. Only around 4 percent are organizations that represent farmers.

The FAO, CGIAR and GACSA like to present CSA “success stories”. Unfortunately, few independent studies to date have examined whether the “win-win-win effects” proclaimed by those responsible for the projects actually reflect complex rural realities.

Kenya Agricultural Carbon Project

The Kenya Agricultural Carbon Project is an often-cited lighthouse project. The World Bank promotes it as a trendsetter for linking CSA with new carbon markets for agriculture. It is being implemented by the Swedish organization SCC-ViA and co-financed by the BioCarbon Fund of the World Bank and the Swedish International Development Cooperation Agency (SIDA). Originally, 60,000 smallholders were slated to convert their agricultural practices on around 45,000 hectares between 2009 and 2030. Shortly after the launch, the target was lowered to 30,000 farmers.

Measures cover surface tillage (conservation agriculture, see above), mulching, agroforestry and water management, as well as Syngenta hybrid seeds and fertilizers. Farmers were said to benefit in two ways: firstly through higher yields, and secondly through the proceeds from the offset credits sold for the carbon stored in the soil. However, due to the low prices per ton of carbon, this only amounts to three dollars per hectare per year at the most – and most families own only one hectare of land. The cheap offset credits can in turn be used by buyers to legitimize their greenhouse gas emissions.

A scientific study carried out in 2017 came to the conclusion that the poorest farming households implemented the measures least – for good reason: They are increasingly confronted with the challenge of reconciling the new climate-friendly agricultural techniques imposed from the outside with their own survival. Reduced tillage or trees on the already limited subsistence area make little sense when there is a food shortage. Programs that focus on carbon sequestration are aimed at something other than the local needs of secure and sustainable food production. Critics also point out that the use of hybrid seed creates new dependencies. Above all, however, the question of the target group arises: Why should smallholders, of all people, be encouraged to store carbon in their subsistence fields, when the majority of emissions come from industrial export-oriented agriculture and livestock production? 

What the CO2 lens overlooks

Measures to prevent the climate crisis are urgently needed. But what happens if carbon storage in agriculture becomes an “ecosystem service” and soils a new “natural capital” in climate protection? Carbon-centric approaches tend to reduce complex measures to combat the climate crisis to mathematical calculations – calculations that sound objective and smart, but are based on inaccurate and selective methods. The impacts of these approaches on complex reality often remain underexposed and power structures are kept hidden.

If land gains in importance, this almost inevitably leads to speculation on valorization and land grabbing. Competition for the type of use arises: Should the land be used for offsetting emissions or for smallholder agriculture? Insurance companies, for example, have increasingly been buying farms or farmland to offset their ecological footprint while also speculating with the land.

In the petition “Our land is worth more than carbon”, dozens of organizations draw attention to the dangers of a purely CO2-focused agricultural approach that distracts from urgently needed major changes in our agricultural and food model toward agroecology and food sovereignty.

While some methods for storing carbon in soils have undeniably important effects on humus formation, biodiversity and food security, others are highly questionable – such as the use of genetically modified seeds and synthetic fertilizers. The CLARA network writes in a briefing that carbon stored in soils through agroecological practices should be seen as a helpful, but not calculable, addition to other necessary emission reductions. Greenhouse gas storage cannot be guaranteed in the long term, so there is no way around leaving fossil fuels in the ground.

“Turning our farmers’ fields into carbon sinks – the rights to which can be sold on the carbon market – will only lead us further away from what we see as the real solution: food sovereignty. The carbon in our farms is not for sale!” says La Via Campesina, the worldwide smallholder movement.


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