Mitigating Climate Change Through Soil Revitalization Using Regenerative Agriculture

In the world’s efforts to combat anthropogenic climate change by achieving net zero emissions, there are two key actions that must be taken on a global level. First, carbon and other GHG emissions need to be reduced and second, more carbon from the atmosphere needs to be sequestered in natural carbon sinks.

Improved Carbon Sequestration through Healthy Soils

Next to forests and oceans, the soil ecosystem is one of the largest carbon sinks in the world. The "4 per 1000" initiative, launched during the 2015 Paris Climate Conference (COP21), proposes that increasing soil organic carbon stocks by only 0.4% annually could significantly counteract global greenhouse gas emissions and thus address the challenges due to climate change (1). The world’s soils contain an estimated 1,500 to 2,400 gigatons (Gt) of organic carbon in the top meter of soil. A 0.4% annual increase in this soil carbon reservoir would mean storing an additional six to ten gigatons of carbon each year. Current global anthropogenic CO2 emissions are around 40 gigatons of CO2 per year which is roughly equivalent to about eleven gigatons of carbon (2) . (3) Thus, at least theoretically, soils potential to offset annual CO2 emissions to reach the goal of net zero is highly significant.

Given this potential of soil, agricultural soils can have a great positive impact in fulfilling global carbon sequestration potentials. Since agricultural lands accounts for 37% (4) of the worlds land surface and contain 50% (5) of world soils, both cropland and pastures yield significant importance when speaking about carbon sequestration. Given the 4 per 1000 initiative’s target of a 4 per 1000 (i.e. 0.4%) rate of annual increase in global soil organic carbon (SOC) stocks, (6) a paper from 2023 estimates that agricultural soils could bind up to 27% of the emissions needed to limit global warming to below 2°C. (7) The important point however: This sequestration potential can only be realized if soils are in a healthy condition.

While healthy soils can be defined in multiple ways given several soil properties and characteristics, soil organic matter content, as a critical component of soil quality, serves as a key indicator of overall soil health due to its influence on biological activity, soil structure, nutrient cycling, and water retention. (8) Healthy soils are rich in organic matter, which plays a crucial role in carbon sequestration since it is primarily composed of carbon, and its presence in the soil enhances the soil's ability to store carbon for long periods. (9) The improved carbon sequestration by healthy soils with rich soil organic matter content in contrast to degraded soils are driven by many processes. For example, healthy soils have improved structure and aggregation, which helps protect organic carbon from decomposition. Good soil structure increases the physical protection of organic carbon within soil aggregates, reducing its exposure to microbial decomposition. (10) Further, healthy soils support a diverse and active microbial community, which plays a vital role in carbon cycling and storage. These microbes help convert plant residues into stable organic matter, effectively locking carbon into the soil. (11) Moreover, healthy soils retain water more effectively, which is crucial for maintaining soil organic matter and supporting plant growth. Better water retention reduces the likelihood of organic matter decomposition and helps maintain carbon stores. (12) In consequence of these improved processes, healthy soils support higher plant productivity, leading to greater biomass input into the soil. This continuous input of organic material from plant roots and residues provides a steady supply of carbon to be sequestered in the soil. (13)

Reduced Greenhouse Gas Emissions using Regenerative Agriculture

So far, this paper highlighted soil’s significant potential in improved carbon sequestration which would rely on improved soil health with an increased content of soil organic matter. A proven and often suggested way of increasing soil organic matter and overall soil health are the principles of regenerative agriculture (RA): Minimize soil disturbance, keep the soil covered, maintain living roots in the soil, maximize plant diversity, reintroduce livestock. These principles can be implemented through specific practices according to both socioeconomic as well as natural conditions like soil type or climate in a specific region. Common practices include no-till farming, cover cropping, crop rotations, composting and the usage of organic amendments or for example the implementation of agroforestry. (14)

While all these principles and practices above have the potential of regenerating soil, the deteriorating state of soil that we see today, on the other hand, is a result of the conventional agriculture that is prevalent throughout the world. Since the Green Revolution modern conventional agriculture is characterized by high levels of synthetic inputs like mineral fertilizers, pesticides and herbicides, heavy machinery and mechanization as well as the adoption of monocultures and managed grazing. (15) Given that agricultural methods worldwide are almost exclusively consist of conventional agriculture, large scale changes in land management have not only the potential to realize healthy soil’s carbon sequestration potentials but also to reduce emissions from the agricultural sector and thus mitigate climate change. Therefore, in this section, this paper examines the potential of reduced carbon emission in consequence of a large scale shift from conventional to RA.

Greenhouse gas (GHG) emissions from agriculture vary significantly across different areas, influenced by factors such as agricultural practices, land use, and the types of crops or livestock produced. There is some uncertainty about the total amount of global greenhouse gas emissions that the agricultural sector is responsible for today. Estimates range from 14 to 30 % of all anthropogenic GHG emissions. (16) Evidence suggests that, over time, global agriculture has become more efficient in terms of GHG emissions. Although production has been rapidly increasing, emissions have increasingly become decoupled from production. By 2007, the global average carbon footprint per unit of crop and livestock produced was 39% and 44% lower, respectively, than in 1970. (17) Since global yield requirements are not projected to decrease and the world needs to intensify its efforts to mitigate climate change, the possibility of an ongoing decoupling from agricultural production and GHG emissions needs to be examined. Given the significant share of global emissions from conventional practices and the before mentioned distinct principles of RA, the next sections will examine how reduced emissions in RA can occur in two ways: directly or indirectly.

Reduced Direct Emissions from Soil through Regenerative Agriculture

As explored in chapter two, soil can help mitigating climate change by taking up more carbon from the atmosphere and storing in underground. However, it is also necessary to keep the existing carbon stock in place to ensure soils do not become sources of carbon emissions. For example, a release of just 1% of the carbon now contained in Europe’s soils alone, would be equal to the annual emissions from 1 billion cars. (18) To avoid direct emissions from soil, practices that maintain or improve soil health as part of the RA framework emerged as an alternative approach to conventional methods in which farmers disturb the soil ecosystem and thus risk carbon releases. The difference in emission between regenerative conservation and conventional tillage methods have received attention for more than 20 years, linking the emission reduction potentials with improvements in soil quality. A comprehensive meta-analysis published in 2016, synthesizing data from 46 peer-reviewed studies and 174 paired observations, investigated the impact of tillage on CO2 emissions across diverse climates, crops, and soil types over entire seasons or years. The analysis revealed that tilled soils emitted an average of 21% more CO2 than untilled soils. Notably, this difference surged to 29% in degraded soils with low soil organic carbon content (<1%). (19) In a more recent, 6-year long field experiment (2017-2022), Mühlbachová et al. (2023), examined the effect of conventional tillage (plowing to 20–22 cm), reduced tillage (chiseling to 10 cm), and no-tillage on carbon emissions on a yearly basis to also account for distinct weather conditions. The study found that RA practices like reduced and no-tillage, with mulch on the surface of the soil, decreased CO2 emissions by a 6-year average of 45% and 51%, respectively. (20) The findings demonstrate that adopting no-tillage practices can significantly minimize carbon dioxide losses from dry land soils, providing a valuable tool in mitigating climate change. (21) In addition, improving soil health can also contribute to realizing additional carbon sequestration benefits as examined in chapter two.

Further, regenerative agriculture leading to healthy soils increases the resilience of ecosystems to climate change by improving water retention, reducing the impact of extreme weather events, and supporting diverse plant and animal communities. This resilience helps maintain stable carbon cycles and reduces the likelihood of carbon release due to environmental stress. (22) For example, healthy soils with good structure and more organic matter content make the land less prone to erosion by wind or water. In consequence, more stable soils keep carbon locked in place. (23) Thus, preventing soil erosion through regenerative practices helps maintain carbon storage instead of emitting it.

Reduced Indirect Emissions from Less Inputs in Regenerative Agriculture

In addition to the direct emissions reductions from the soil, the transition from conventional to regenerative agriculture can further decrease emissions by impacting the industries that conventional agriculture heavily relies upon. (24) Conventional agriculture is heavily dependent on synthetic inputs, such as mineral fertilizers, which have significantly increased since the Green Revolution. The production of these inputs is a significant source of global carbon emissions. (25)

According to Menegat et al. (2022), the synthetic nitrogen fertilizer supply chain was responsible for estimated emissions of 1.13 GtCO2e in 2018, representing 10.6% of agricultural emissions and 2.1% of global GHG emissions - an amount comparable to the aviation industry. (26) While regenerative agriculture does not necessarily exclude synthetic inputs, the adoption of regenerative practices results in reduced use during the transition and minimal use after the transition is complete. If applied on a large scale, the reduced use of synthetic inputs, such as nitrogen fertilizers, would lead to less production and transportation, thereby reducing carbon emissions.

A study from the University of Cambridge in 2023 estimates that emissions from fertilizers could be reduced by as much as 80% by 2050, bringing emissions down to one-fifth of current levels without affecting productivity. The researchers argue that the current use of fertilizers is economically inefficient and that more efficient use would significantly reduce emissions without compromising crop productivity. (27) By adopting regenerative agriculture practices, farmers can reduce their production costs and contribute to a lower carbon footprint for the agriculture industry as a whole. This shift can potentially create a more sustainable and environmentally friendly agricultural system. The World Economic Forum also estimates that greenhouse gas emissions from agriculture could be 6% lower annually by 2030 if a fifth of farmers adopted climate-smart agriculture practices, such as regenerative farming. (28) Furthermore, the Rodale Institute has found that regenerative organic agriculture can sequester more carbon than is currently emitted, potentially reversing climate change. (29) And a global switch to regenerative crop and pasture systems could draw down more than 100% of annual CO2 emissions. (30)

Summary

This paper highlights the critical role of soil revitalization through regenerative agriculture (RA) in mitigating climate change. The realization of soil's global carbon sequestration potential, estimated to offset up to 27% of emissions needed to limit global warming to below 2°C, hinges on maintaining healthy soils. Regenerative agriculture, characterized by practices such as minimal soil disturbance, permanent soil cover, and maximized plant diversity, is essential for achieving and preserving soil health. Regenerative agriculture not only enhances soil carbon sequestration but also reduces carbon emissions in two ways: directly, by minimizing soil disturbance and promoting soil health, resulting in reduced CO2 emissions from soil; and indirectly, by decreasing the use of synthetic inputs, such as mineral fertilizers, which account for about 2% of global greenhouse gas emissions.

A large-scale shift from conventional to regenerative agriculture can significantly reduce total carbon emissions while unlocking soil's carbon sequestration potential. By adopting RA practices, the agricultural sector can decrease its substantial share of global emissions (14-30%) and contribute meaningfully to achieving net-zero emissions. This transition necessitates a fundamental change in agricultural practices, prioritizing soil health and biodiversity to ensure a resilient and sustainable food system. Ultimately, this paper underscores the imperative of integrating regenerative agriculture into global climate change mitigation strategies, recognizing the profound impact of soil health on carbon sequestration and emission reduction. By harnessing the potential of RA, we can unlock a critical pathway toward achieving net-zero emissions and ensuring a climate-resilient future.

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