10 Types of Carbon Sequestration

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. This is done by the different types of Carbon Sequestration

Carbon dioxide is a heat-trapping gas produced both in nature and by human activities. Man-made carbon dioxide can come from burning coal, natural gas, and oil to produce energy.

Biologic carbon dioxide can come from decomposing organic matter, forest fires, and other land use changes.

The buildup of carbon dioxide and other ‘greenhouse gases’ in the atmosphere can trap heat and contribute to climate change. The process of carbon sequestration can delay the warming of the atmosphere.

Carbon sequestration secures carbon dioxide to prevent it from entering the Earth’s atmosphere.

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.”

What is Carbon Sequestration?

Carbon sequestration is the practice of capturing or removing carbon from the atmosphere and storing it. It is one of the many approaches put in place to address the issue of climate change.  

It can also mean the removal of greenhouse gases from the atmosphere and putting them into long-term carbon storage to prevent the warming of the planet.

Preventing the earth’s atmosphere from warming any further is taking a huge collective effort by humanity. From ending our dependency on carbon-emitting fuels to establishing a net zero emissions target by 2050, every potential solution is important if we’re to stop unprecedented climate change.

Alongside a transition to clean energy systems and decarbonizing high-emission practices such as construction or transport. Humanity is making a concerted effort to remove carbon from our atmospheres, by adapting the ways we construct, consume, travel, and generate power.

But methods like carbon sequestration show how we can work with the natural environment to tackle the climate crisis.

What is involved in the process of Carbon Sequestration?

Carbon capture and sequestration follow a three-step process that includes:

• Capture or Securing  of Carbon dioxide from industrial processes or power plants
• Transport of the captured and compressed Carbon dioxide
• Storage of Carbon oxide into deep underground rock formations

Types of Carbon Sequestration

With industries around the world emitting 10 Gigatonnes (one billion metric tonnes) of GHGs every year, the need for carbon sequestration is dire.

Here are some types of carbon sequestration that will help you address global warming and climate change on an individual basis.

• Sequestration in Forests
• Sequestration in Soils
• Direct Air Capture (DAC) and Storage
• Sequestration in Grasslands
• Wetland Sequestration
• Ocean Carbon Sequestration
• Carbon Capture and Storage (CCS) Power Plant
• Engineered Molecules
• Geological Carbon Sequestration
• Industrial Carbon Sequestration

1. Sequestration in Forests

Forests and woodlands are recognized as one of the best forms of natural carbon sequestration.

On average, forests store twice as much carbon as they emit, while an estimate of about 25% of carbon emissions are sequestered by forest-rich landscapes such as rangelands and grasslands (fields, prairies, shrublands, etc.).

When the trees, branches, and leaves die and fall to the ground, they release the carbon they had stored into the soil.

Securing and conserving such natural environments is therefore crucial to ensuring carbon sinks capture CO2 effectively. Wildfires and human activities such as deforestation, construction, or intensive agriculture pose the biggest threat to this natural process.

2. Sequestration in Soils

Carbon can be captured in soil by plants through photosynthesis and can be stored as soil organic carbon (SOC).

As such, agroecosystems degrade and deplete the soil’s organic carbon levels. Also, through bogs, peat, and swamps, carbon can be captured and stored as carbonates.

These carbonates build up over thousands of years as CO₂ mixes with other mineral elements, such as calcium or magnesium minerals, forming “caliche” in the desert and arid soil.

Eventually, this carbon stored in the carbonates is released from the earth, but not for a very long time—after more than 70,000 years in some cases while the soil organic matter stores carbon for several years.

Scientists are working on ways to accelerate the carbonate-forming process by adding finely crushed silicates to the soil in order to store carbon for longer periods of time.

3. Direct Air Capture (DAC) and Storage

This approach uses chemicals or solids to capture the gas from thin air, then, as in the case of BECCS, stores it for the long haul underground or in long-lasting materials.

It is a means by which carbon is captured directly from the air using advanced technology plants. It has been discovered that direct air capture theoretically can remove CO₂ from the air a thousand times more efficiently than plants.  

This process is already used in submarines beneath the surface of the ocean and in space vehicles far above it. However, this process is energy intensive and expensive, ranging from $500-$800 per ton of carbon removed.

While techniques such as direct air capture can be effective, they are still too costly to implement on a mass scale.

Examples are carbon-sequestering containers from Arizona State University’s Lackner, along with other projects such as Climeworks’ just-opened carbon-trapping facility in Switzerland.

4. Sequestration in Grasslands

While forests are commonly credited as important carbon sinks, grasslands can also sequester more carbon underground and when they burn, the carbon stays fixed in the roots and soil instead of in leaves and woody biomass.

Grasslands and rangelands are more reliable areas of storing carbon than forests due to the rapid wildfires and deforestation affecting forests.

However, forests have the ability to store more carbon than grasslands, but in unstable conditions due to climate change, grasslands can be more resilient.

5. Wetland Sequestration

Like all plants, wetland plants take up carbon from the air in the form of carbon dioxide and store that carbon in biomass. They are known as important natural assets, capable of taking up atmospheric carbon and restricting subsequent carbon loss to facilitate long-term storage.

They can be deliberately managed to provide a natural solution to mitigate climate change as well as to help offset direct losses of wetlands from various land use changes and natural drivers. Furthermore,  Wetlands such as peat bogs capture carbon with a higher density of carbon per hectare than forest or agricultural land.

6. Ocean Carbon Sequestration

Aquatic environments and large bodies of water are also great absorbers of CO₂. Oceans absorb from the atmosphere about 25 percent of carbon dioxide emitted from human activities annually.

Carbon goes in both directions in the ocean. When carbon dioxide releases into the atmosphere from the ocean, it creates what is called a positive atmospheric flux. A negative flux refers to the ocean absorbing carbon dioxide. Think of these fluxes as an inhale and an exhale, where the net effect of these opposing directions determines the overall effect.

Colder and nutrient-rich parts of the ocean are able to absorb more carbon dioxide than warmer parts. Therefore, the Polar Regions typically serve as carbon sinks. By 2100, much of the global ocean is expected to be a large sink of carbon dioxide. This carbon is mostly held in the upper layers of the oceans. However, excessive carbon can acidify the water, posing a threat to the biodiversity that exists below.

7. Carbon Capture and Storage (CCS) Power Plant

CCS involves capturing carbon dioxide that’s been produced by power generation or industrial activity, such as cement or steel-making. This CO₂ is then compressed and transported to deep underground facilities, where it’s injected into rock formations for permanent storage.

8. Engineered Molecules

Scientists are engineering molecules that can change shape by creating new kinds of compounds capable of securing and capturing carbon dioxide from the air.

The engineered molecules act as a filter, only attracting the element it was engineered to seek. In practice, this could present an efficient way of creating raw materials while reducing atmospheric carbon.

9. Geological Carbon Sequestration

This process deals with the storage of carbon dioxide in underground geologic formations, such as in rocks.

Carbon dioxide is captured from industrial sources of carbon dioxide such as steel or cement production companies or energy-related sources like power plants or natural gas processing facilities, which is then injected into porous rocks for long-term storage.

Such carbon capture and storage allows the use of fossil fuels until another energy source is introduced on a large scale

10. Industrial Carbon Sequestration

This may not be a widely accepted and efficient type of carbon sequestration, but it can be used in some industries. They capture the carbon in three ways from a power plant, pre-combustion, post-combustion, and oxyfuel.

Pre-combustion deals with the capture of carbon in power plants before the fuel are burned. The aim is to remove the carbon from coal before it is burned.

In post-combustion, carbon is removed from a power station’s output after the fuel has been burned. This means waste gases are captured and scrubbed clean of their carbon dioxide before they travel up smokestacks. This is achieved by passing the gases through ammonia, which is then blasted clean with steam, releasing carbon dioxide for storage.

While oxyfuel or oxy-combustion fuel is burned, it takes in more oxygen and stores all the gases produced as a result. Instead of laboriously separating the carbon dioxide from other waste gases, the process traps the entire output from the smokestacks and stores it all.

Pure oxygen is blown into the furnaces to purify the exhaust, so the fuel burns completely, producing relatively pure steam and carbon dioxide gas.

Once the steam is removed by cooling and condensation, making it into the water, the carbon dioxide can be safely stored.

Conclusion

To conclude this article, carbon sequestration by these different types has favored environmental sustainability inasmuch as there are daily carbon-producing activities in the environment mostly due to human activities.

Therefore it is very important that these methods and types of carbon sequestration be implored so as to save and sustain the environment.

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