5 Carbon Sink Examples Explained

Carbon sink examples are; plants, geologic formations, soil, oceans, and inland wetlands.

This article discusses carbon sink examples, as follows;



1). Plants (as one of the Carbon Sink Examples)

Plants are examples of natural carbon sinks.

The mechanism by which plants absorb and store carbon is photosynthesis [5].

Because carbon dioxide is a major requirement for photosynthesis, this process can lead to significant reduction of carbon concentration in the atmosphere.

It implies that photosynthesis is a natural mechanism for establishing sustainability in the ecosystem. Also, photosynthesis has positive implications with regards to mitigating environmental degradation in the form of greenhouse emission, climate change, desertification and global warming.

Plants as carbon sinks may occur in the form of forest, grassland, tundra, aquatic or agricultural vegetation.

The role of plants in carbon capture and storage or sequestration, coincides with their role as primary producers of biomass and bioenergy.

Through photosynthesis, plants introduce chemical energy into the ecosystem, which is then circulated to other organisms through feeding and biodegradation processes, in a hierarchical sequence known as the energy pyramid.

Based on the above explanation, it is possible to correlate the carbon sequestration activities of plants with energy conservation and energy efficiency in natural ecosystems. This is because the carbon captured by plants is used for energy-producing and energy-conserving activities.

Carbon stored by plants is usually released back into the atmosphere when these plants become inactive.

This may occur either through death and biodegradation of the plant, or through deforestation practices. As a result, deforestation is simultaneous with climate change and global warming [2].


2). Geologic Formations

Geologic formations are one of the most common examples of carbon sinks.

These include earth materials located in the subsurface.

Geologic formations are especially good for efficient long-term storage of carbon. Because these formations occur deep underground, they usually provide optimal conditions for carbon storage in terms of pressure, temperature and other physicochemical factors.

Underground geologic formations may comprise of soil, sedimentary rocks like limestone and sandstone, fossil fuels like coal, and hydrocarbons like petroleum. Carbon dioxide can be securely trapped beneath layers of such materials.

The introduction of carbon dioxide into underground geologic formations can occur naturally, through processes involving plants, animals and microbes; or may occur artificially.

As part of efforts to achieve sustainable development and circular economy, carbon capture and storage technologies have been developed, which help to introduce large volumes of carbon dioxide into underground geologic formations by injection [4].

Carbon stored in geologic formations can be released back into the atmosphere through drilling, mineral exploration, raw material extraction, and construction activities.


3). Soil (as one of the Carbon Sink Examples)

The role of soil as a carbon sink is similar to that of underground geologic formations.

However, ‘soil’ only covers the top soil, and shallow subsurface layers.

Various mechanisms can lead to carbon sequestration in soils, although the most common of these involve plants, microorganisms, and biochemical reactions.

Carbon storage is significant in soils covered by vegetation or glacier. This includes forest soils, and permafrost soils in temperate regions [6].

Although soils store very large amount of carbon dioxide, they are one of the most unstable and unreliable examples of carbon sinks. This is because soil is highly susceptible to various forms of alteration and disturbance, in the course of erosion, agriculture, mining and construction, among other processes.

To make soil an efficient and reliable carbon sink requires the application of soil conservation and sustainable farming practices like crop rotation, contour farming, mulching, composting and cover cropping.


4). Oceans

Oceans constitute one of the most significant and prominent examples of carbon sinks.

The significance of oceans for storing carbon can be attributed to their scale and complexity.

In terms of scale, oceans cover up to 70% of the Earth’s surface. This indicates that the ocean is an abundant natural resource.

With regards to complexity, oceans are elaborate ecosystems. They contain nearly all other examples of carbon sinks, as components of the marine ecosystem. This includes soil, water, plants, coral reefs, and underground geologic formations.

Due to the presence of multiple carbon absorbers, oceans are highly effective for storing carbon. It is estimated that the world’s oceans contain nearly 33% of the total volume of anthropogenic carbon dioxide on Earth [1].

Oceans are also relatively stable as carbon sinks, compared to soil and vegetation that are susceptible to interference and alteration.

Carbon Sink Examples: Oceans (Credit: Ricardo Pravettoni 2009)
Carbon Sink Examples: Oceans (Credit: Ricardo Pravettoni 2009)


5). Inland Wetlands (as Examples of Carbon Sinks)

Inland wetlands include swamps, floodplains, rivers, ponds, marshes, fens and lakes [3].

These systems are ideal for carbon storage especially due to their low mobility. Because the water flow rate in such systems does not disrupt internal biochemical and biological processes, they are stable and are not susceptible to interferences that can cause release of carbon dioxide into the atmosphere.

Also, the presence of clayey soils and aquatic plants in such systems, facilitates carbon storage.

Inland wetlands are susceptible to pollution due to their exposure, and can be converted to carbon sources as a result of degradation.

Carbon Sink Examples: Inland Wetlands (Credit: USFWSmidwest 2009 .CC BY 2.0.)
Carbon Sink Examples: Inland Wetlands (Credit: USFWSmidwest 2009 .CC BY 2.0.)



Carbon sink examples are;

1. Plants

2. Geologic Formations

3. Soil

4. Oceans

5. Inland Wetlands



1). Adams, E.; Caldeira, K. (2008). “Ocean storage of CO2.” Elements 4(5):319-324. Available at: https://doi.org/10.2113/gselements.4.5.319. (Accessed 12 September 2022).

2). Ali, A.; Riaz, S.; Iqbal, S. (2014). “Deforestation And Its Impacts On Climate Change An Overview Of Pakistan.” Papers on Global Change IGBP 21(1). Available at: https://doi.org/10.1515/igbp-2015-0003. (Accessed 12 September 2022).

3). Balwan, W. K.; Kour, S. (2021). “Wetland-An Ecological Boon for the Environment.” Available at: https://doi.org/10.13140/RG.2.2.15728.79368. (Accessed 12 September 2022).

4). Benson, S. M. (2005). “Carbon Dioxide Capture and Storage in Underground Geologic Formations.” Available at: https://www.researchgate.net/publication/228389554_Carbon_Dioxide_Capture_and_Storage_in_Underground_Geologic_Formations. (Accessed 12 September 2022).

5). Voronin, P. Y. (2006). “Chlorophyll index and photosynthetic carbon sequestration in Northern Eurasia.” Russian Journal of Plant Physiology 53(5):689-697. Available at: https://doi.org/10.1134/S1021443706050141. (Accessed 12 September 2022).

6). Zimov, N. S.; Zimov, S. A.; Zimova, G. M.; Chuprynin, V. I.; Chapin, F. S. (2009). “Carbon storage in permafrost and soils of the mammoth tundra-steppe biome: Role in the global carbon budget.” Geophysical Research Letters 36(2). Available at: https://doi.org/10.1029/2008GL036332. (Accessed 12 September 2022).

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