In simple words, soil carbon sequestration takes place when plants detain and store, or “sequester,” carbon dioxide (CO2) from the atmosphere in the soil, multiplying the soil’s carbon content. Decaying plant notes, along with their constituent carbon, become a component of soil for a phase before microbes break them down, an action that releases the atmospheric carbon.
This article will discuss Soil Carbon Sequestration in the context of the IAS Exam.
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Benefits of Soil Carbon Sequestration
- The period for which the soil can hold onto carbon before releasing it back into the atmosphere varies depending on the earth’s conditions. These include climate composition, among other factors.
- In this regard, converting the soil structure by changing grasslands and forests to farmland may hasten the process. This, in turn, will free most of the soil’s carbon content again into the atmosphere. Conversely, practices such as planting cover crops and no-till farming can reduce the rate at which soil loses carbon and even raise soil carbon levels.
- Last 12,000 years (especially the preceding 200 years) of agriculture has reported approximately 133 billion metric tons of CO2 (GtCO2) adding to the atmosphere from soil. That is approximately three times the amount of carbon that all human activities released in 2019, which was 43.1 GtCO2. Cultivated soils have released almost 70 per cent of their original carbon content in some places. Sometimes individuals advocating “carbon farming” or soil carbon sequestration say that modifying farming techniques can help the soil regain some amount of that carbon.
Storing Carbon in Agricultural Soils
- Cropland is the main target for soil-based carbon sequestration. Farmers can add extra carbon to agricultural soils by sowing certain crops. For example, perennial crops, which do not die off yearly, increase deep roots that help soils stock more carbon. “Cover crops” like beans, clover and peas, planted after the main crop is harvested, help soils take in carbon year-round, and plug under the ground as “green manure”, which adds up more carbon to the soil.
- By splitting up the earth, tilling prepares land for new crops, helps control weeds, and releases a lot of stored carbon.
- Proponents argue that farming practices that store more carbon can also improve soil health and food production.
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Potential Climate Benefits of Soil Carbon Sequestration
- As carbon is the fundamental GHG resulting from human activities, carbon farming could add to goals of climate mitigation.
- Approximates for the amount of carbon that can be stored differ broadly. The Intergovernmental Panel on Climate Change (IPCC) states that worldwide soil carbon sequestrations have the technical ability to mitigate up to approximately 5.3 GtCO2 every year by 2030.
Are There Any Challenges to Soil Carbon Sequestration?
Still, there is common scepticism regarding if carbon sequestration can match its acclaimed ability.
- Scientists are unaware of how to store long carbon in the soil, successfully measure and track sequestered carbon, and how many different practices can sequester carbon.
- Moreover, understanding of soil science has changed over time. New studies contradict the thought that the IPCC’s approximates rely on the theory that the soil can store carbon-rich, stable molecules for up to thousands of years.
- Former assumptions state that other ways of carbon farming, such as afforestation, are much easier to assess than carbon sequestration in soil due to the impermanent and dynamic nature of the earth. Moreover, there is increasing evidence that several practices, including no-till farming do not really store the amount of carbon that theoretical assumptions stated.
- Another challenge to this practice is that there will eventually be a saturation level of soil carbon content. According to some approximates, researchers can arrive at these levels within some decades, at which end there has to be other sources to offer further mitigation.
It is approximated that soils can sequester about 20 Pg C in 25 years, more than 10 % of anthropogenic emissions. At the same time, this process provides other significant benefits for soil, environment quality and crop, avoidance of erosion and desertification, and improved bio-diversity. On the other hand, land degradation does not only low crop yields but often decreases the carbon content of cultivation and may reduce biodiversity. Therefore, it is vital to identify the significant synergies in soil carbon sequestration between the three UN conventions: UNFCC, UNCBD and UNCCD.
Carbon sequestration actions have been supported through the Clean Development Mechanism (CDM) under the Kyoto protocol. This protocol focused on afforestation and reforestation, which are the most essential and readily measurable means to sequester carbon as biomass both below and above ground.
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Frequently Asked Questions about Soil Carbon Sequestration
How long can soil store carbon?
Scientists believe soils could continue to sequester carbon for 20 to 40 years before they become saturated. Most crops are annuals, so farmers often leave fields bare after harvest.
What is the best way to sequester carbon?
Sequestering carbon in its natural sinks, such as soil, grasslands, and forests, makes for the best way to remove it. Therefore, achieving the 1.5°C target calls for speedy increase in the natural carbon sinks’ capacity to absorb atmospheric carbon. This is also necessary to fight desertification.
How do you calculate carbon sequestration in plants?
Individuals can determine the weight of CO2 in plants by the proportion of CO2 to C is 44/12 = 3.67. Hence, to assess the significance of carbon dioxide sequestered in the tree, multiply the weight of carbon in the tree by 3.67.
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