Carbon sequestration - processes and methods

Environmental concerns - greenhouse gases - natural processes.

Author: Charitarth Sindhu, Environmental Sustainability & ESG Consultant

Carbon sequestration refers to the process of capturing atmospheric carbon dioxide (CO₂) and securely storing it within various physical or biological systems. This method, whether facilitated through natural mechanisms, technological innovations, or a blend of both, aims to diminish carbon footprints and stabilize greenhouse gas concentrations in the atmosphere.

The process

Carbon sequestration entails the capture and containment of carbon-based by-products like CO₂ and methane before their release from significant industrial sources, such as fossil fuel-powered facilities.

These captured carbon sources are then deposited into deep underground rock formations or introduced into carbon sinks like oceans, forests, or soils. The overarching goal is to combat climate change and mitigate global warming.

Carbon sinks

Any system that absorbs more carbon than it emits functions as a carbon sink. This carbon sink acts as a reservoir—either artificial or natural—that accumulates and stores atmospheric carbon within physical and biological environments.

Carbon sinks play a critical role in mitigating climate change by reducing greenhouse gas concentrations. They serve as essential buffers against excessive CO₂ build up which is a primary driver of the greenhouse effect and subsequent global warming.

Types of carbon sinks

Terrestrial: This category encompasses forests, grasslands, wetlands, and soils. Among these, tropical rainforests, due to their robust photosynthetic capacity, stand out as particularly effective carbon sinks.

Oceanic: The ocean ecosystem plays a pivotal role in absorbing CO₂ from the atmosphere. Marine organisms, such as phytoplankton, utilize CO₂ for photosynthesis. Upon their death, organic matter sinks to the ocean floor, effectively sequestering carbon.

Geological: Geological carbon sinks include underground formations like depleted oil and gas reservoirs, saline aquifers, and deep ocean sediments. Technologies like Carbon Capture and Storage (CCS) leverage these geological structures to permanently store captured CO₂ from industrial processes.

Methods of carbon sequestration

Natural methods: The soil, oceans, plants, and animals serve as natural carbon sinks or sponges. All organic life on Earth is carbon-based, and when plants and animals perish, a large portion of the carbon returns to the ground, where it affects global warming. During growth, plants and trees use photosynthesis to take in and store carbon dioxide while releasing oxygen. This process assists in removing carbon dioxide from the air.

Artificial methods: involve capturing carbon emissions at the source (such as factory chimneys) and then burying them. Some popular methods include utilizing carbon by-products for graphene production, a vital component in the production of tech devices like smartphones or computer processors.

Carbon Capture and Storage (CCS), captures CO₂ from fossil fuel-based power generation or industrial activities such as cement or steel-making. This captured CO₂ is subsequently compressed and injected into rock formations for permanent storage.

Conclusion

Prioritising the conservation and restoration of carbon sinks presents a critical opportunity to leverage their substantial potential in safeguarding the Earth's climate, biodiversity, and the well-being of future generations. By preventing the planet's temperature from exceeding a 2°C increase, concerted efforts in carbon sequestration can help mitigate the impacts of climate change.

See also

• Carbon capture
• Carbon capture utilisation and storage (CCS)
• Carbon footprint
• Carbon sequestration
• Carbon sink
• Climate change
• Global warming
• Greenhouse gas
• United Nations Environment Programme (UNEP)
• United Nations Framework Convention on Climate Change (UNFCCC)

Other resources

• UNFCCC resources - Carbon capture

• UNEP - Carbon Dioxide Capture and Storage

• The National Grid - What is carbon sequestration?