Carbon Sequestration

Carbon sequestration is the long-term carbon storage in plants, soils, geological formations, and the ocean. The monitoring of carbon storage is important for Climate Action (SDG 13). Read here to understand more about carbon sequestration.

The most often produced greenhouse gas is carbon dioxide. The technique of removing and storing carbon dioxide from the atmosphere is known as carbon sequestration.

It is one way to lessen atmospheric carbon dioxide to slow down the rate of climate change.

The two major types of carbon sequestration are geologic and biologic.

Sustainable Development Goal 13 (SDG 13: Climate Action), which focuses on taking immediate action to address climate change and its effects, is in line with research into carbon sequestration.

Carbon sequestration

The long-term storage of carbon in vegetation, soil, rock formations, and the ocean is known as carbon sequestration.

Carbon is often stored through the process of carbon sequestration, which can happen both naturally and as a result of human activity.

The idea is to stabilize carbon in solid and dissolved forms so that it doesn’t cause the atmosphere to warm. The process shows tremendous promise for reducing the human “carbon footprint.”

Learning how to capture and store carbon dioxide is one way scientists want to defer the effects of warming in the atmosphere.

This practice is now viewed by the scientific community as an essential part of solving climate change.

Also read: Kyoto Protocol, 1997

Types of carbon sequestration

There are majorly three types of Carbon sequestration:

Terrestrial

• Terrestrial carbon sequestration is the process through which CO₂ from the atmosphere is collected by trees and plants during photosynthesis and stored as carbon in soils and biomass (tree trunks, branches, foliage, and roots)

Geologic

• Carbon dioxide can be stored in a variety of locations, including oil and gas deposits, non-mineable coal seams, saline formations, and shale formations with significant organic content.

Ocean

• It entails the seas absorbing, releasing, and storing a significant amount of CO₂ from the atmosphere.
• There are two ways to achieve this: either by fertilizing the ocean with iron to increase its biological productivity or by injecting CO₂ into the deep sea.
• The release of iron enhances phytoplankton production, which in turn boosts photosynthesis and aids in CO₂

Carbon sequestration methods

The methods or process involved in carbon sequestration or carbon capture occurs naturally, but are encouraged artificially as well-

Natural/biological processes on land

• Biosequestration is the capture and storage of the atmospheric greenhouse gas carbon dioxide by continual or enhanced biological processes.
• Peat bogs act as a sink for carbon because they accumulate partially decayed biomass that would otherwise continue to decay completely.
• Afforestation, proforestation, and reforestation to incorporate carbon from atmospheric CO₂ into biomass.

Afforestation is the establishment of a forest in an area where there was no previous tree cover. Proforestation is the practice of growing an existing forest intact toward its full ecological potential. Reforestation is the replanting of trees on marginal crop and pasture lands.

• Urban forestry increases the amount of carbon taken up in cities by adding new tree sites and the sequestration of carbon occurs over the lifetime of the tree.
• Wetland restoration has been proposed as a potential climate change mitigation strategy, with carbon sequestered this way known as blue carbon.
• Modification of agricultural practices is a recognized method of carbon sequestration as the soil can act as an effective carbon sink offsetting as much as carbon dioxide emissions annually.
• Carbon farming is a name for a variety of agricultural methods aimed at sequestering atmospheric carbon into the soil and in crop roots, wood, and leaves. Carbon farming aims to increase the rate at which carbon is sequestered into soil and plant material to create a net loss of carbon from the atmosphere.

Physical processes

• Bio-energy with carbon capture and storage (BECCS) refers to biomass in power stations and boilers that use carbon capture and storage.
• Burying biomass (such as trees) directly mimics the natural processes that created fossil fuels.
• The addition of biochar (charcoal created by pyrolysis of biomass waste) is a novel strategy to increase the soil-carbon stock for the long term and to mitigate global warming by offsetting atmospheric carbon.

Chemical processes

• Carbon, in the form of CO_2, can be removed from the atmosphere by chemical processes called “carbon sequestration by mineral carbonation” or mineral sequestration, and stored in stable carbonate mineral forms.

Technological processes

• The use of carbon dioxide as a raw material to produce graphene, which is a solution for reducing emissions from the atmosphere.
• Direct Air Capture (DAC) enables to capture of carbon directly from the air using advanced technology plants.
• Engineered molecules can change shape by creating new kinds of compounds capable of singling out and capturing carbon dioxide from the air.

Forests as Carbon sinks for sequestration

Depending on their characteristics and local circumstances, forests can play different roles in the carbon cycle, from net emitters to net sinks of carbon.

• Forests sequester carbon by capturing carbon dioxide from the atmosphere and transforming it into biomass through photosynthesis.
• Sequestered carbon is then accumulated in the form of biomass, deadwood, litter, and in forest soils.
• The release of carbon from forest ecosystems results from natural processes (respiration and oxidation) as well as deliberate or unintended results of human activities (i.e., harvesting, fires, deforestation).

When the net balance of carbon emissions by forests is negative, i.e., carbon sequestration prevails, forests contribute to mitigating carbon emissions by acting as both a carbon reservoir and a tool to sequester additional carbon.

In cases when the net balance of carbon emissions is positive, forests contribute to enhancing the greenhouse effect and climate change.

Forests and their role in the carbon cycle are affected by changing climatic conditions.

• Evolutions in rainfall and temperature can have either damaging or beneficial impacts on forest health and productivity, which are very complex to predict.
• Depending on circumstances, climate change will either reduce or increase carbon sequestration in forests, which causes uncertainty about the extent to which the world’s forests will be able to contribute to climate change mitigation in the long term.
• Forest management activities have the potential to influence carbon sequestration by stimulating certain processes and mitigating the impacts of negative factors.

Impact of Carbon Sequestration

Earth’s forests, farms, and grasslands have historically absorbed about 25% of human carbon emissions.

For plants to flourish and sequester carbon, scientists and land managers are working to maintain landscapes vegetated and the soil moist.

The ocean’s upper layer absorbs up to 30% of the carbon dioxide that humans release when we burn fossil fuels.

However, this increases the acidity of the water, and ocean acidification makes it more difficult for marine life to develop their shells.

To track changes brought on by carbon sequestration and modify fishing techniques, scientists and the fishing industry are taking proactive measures.

-Article written by Swathi Satish