What is carbon sequestration? A beginner's guide

Carbon sequestration is a process that could be key to reducing greenhouse gases in the atmosphere—and ultimately slowing down global warming. But what does it actually mean? 

In this beginner-friendly guide, we’ll break down what carbon sequestration is, how it works, and why it matters.

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What is carbon sequestration?

Carbon sequestration is the process of capturing and storing carbon dioxide (CO₂), one of the main greenhouse gases responsible for warming the planet. Through sequestration, we aim to reduce CO₂ levels in the atmosphere by “locking it away” for long periods, either in natural reservoirs like forests and soil or in artificial storage solutions.

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How does carbon sequestration work?

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There are two main types of carbon sequestration: natural and artificial. Each has unique processes for trapping and storing carbon.

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1. Natural carbon sequestration

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In nature, carbon sequestration occurs through the carbon cycle. Ecosystems such as forests, oceans, and soil rely on trees, plants, and algae to absorb CO₂ from the atmosphere during photosynthesis. In this process, they use the carbon to create their tissues and release oxygen (O₂) back into the atmosphere as a byproduct. Wetlands, forests, and agricultural systems are dynamic, with carbon constantly flowing through them.

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Young, fast-growing forests typically store more carbon, while older forests reach a balanced state where carbon intake through photosynthesis is offset as part of the carbon cycle.  In relative terms; by sequestering more carbon than is released, they create long term carbon sinks.

2. Artificial (or engineered) carbon sequestration
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Engineered sequestration technologies aim to capture CO₂ directly from industrial emissions or even from the air itself. Techniques like carbon capture and storage (CCS) collect CO₂ from power plants or factories and inject it deep underground into geological formations. Although this approach requires specialized infrastructure, it has the potential to remove large amounts of CO₂ from areas where emissions are high.

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Why is carbon sequestration important?

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The urgency of carbon sequestration lies in its role in tackling climate change. Here’s why it matters:

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• Reducing atmospheric CO₂
  Every ton of CO₂ removed from the atmosphere slows the pace of global warming, helping us get closer to climate targets like those outlined in the Paris Agreement.
• Complementing emissions reduction
  While reducing emissions is critical, some sectors (like cement and steel production) are challenging to decarbonize completely. Carbon sequestration acts as an additional tool to offset these unavoidable emissions.
• Protecting ecosystems
  Natural sequestration methods, like reforestation and soil conservation, support biodiversity and protect ecosystems, helping them thrive while also capturing carbon.

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Types of natural carbon sinks

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Let’s explore a few key natural systems that help store carbon:

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• Forests: Forests are one of the most effective natural carbon sinks, with trees and soil acting together to capture CO₂. Forest conservation and reforestation initiatives have become important for enhancing the rate of natural carbon stores.
• Soil: Healthy soils can store substantial amounts of carbon, especially in agricultural settings that use regenerative practices like crop rotation and cover crops. Sustainable soil management enhances its carbon storage potential.
• Mangroves: Mangroves are coastal ecosystems that excel at sequestering carbon. Their dense root systems store carbon both above ground in their biomass and below ground in the surrounding sediment, making them vital for combating climate change and protecting coastlines. (In fact, studies have found that mangroves sequester carbon 2–4 times more effectively than mature tropical forests and contain the highest carbon density of all terrestrial ecosystems).
• Oceans: Oceans absorb about a quarter of human-produced CO₂, thanks to processes like the carbon cycle. Phytoplankton, small organisms in the ocean, capture CO₂ during photosynthesis, making oceans a vast carbon reservoir.

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How carbon sequestration ties into carbon credits

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For industries looking to offset their carbon footprint, carbon credits offer a way to invest in sequestration projects. Companies can purchase carbon credits, which represent a certain amount of CO₂ removed from the atmosphere through sequestration efforts. These credits can support projects like reforestation, soil enhancement, or CCS installations, helping businesses balance out emissions that are otherwise hard to eliminate.

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The challenges and future of carbon sequestration

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While carbon sequestration holds promise, challenges remain:

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• Cost and technology: CCS and other engineered sequestration methods can be expensive and require specialized infrastructure. Making these methods affordable and widely accessible is a goal for the future.
• Scaling natural methods: Nature-based solutions like reforestation require vast land areas to make a dent in atmospheric CO₂. Balancing land use for food production, conservation, and carbon sequestration is a complex issue.

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While it may not be a complete solution, technologies and projects that aim to ensure sequestration outcompete emissions can be a powerful pathway towards net zero. Whether through the preservation of forests, healthier soils, or cutting-edge capture technology, these methods allow us to reduce the amount of CO₂ lingering in our atmosphere, providing a path toward a more sustainable future.

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