Carbon sequestration is the process of capturing and storing atmospheric carbon dioxide (CO 2) to reduce its presence in the atmosphere. It serves as a critical climate change mitigation strategy, utilizing both natural ecosystems and advanced technologies to create long-term carbon sinks.
Carbon sequestration refers to a set of methods aimed at capturing atmospheric CO 2 and locking it away for long periods, preventing it from contributing to global warming. As excess CO 2 is the primary driver of climate change, its removal and storage are essential components of global decarbonization efforts. This process is vital for industries aiming to achieve net-zero emissions and for governments striving to meet international climate targets like those outlined in the Paris Agreement.
The methods for sequestering carbon are diverse and can be broadly divided into two main categories:
- Biological Sequestration: This approach leverages natural processes. It is the storage of carbon in vegetation, soils, and oceans.
- Forests: Through photosynthesis, trees absorb CO 2 and store it in their biomass (trunks, leaves, roots) and in forest soils. Afforestation (planting new forests) and reforestation (restoring old ones) are key strategies here.
- Soils: Agricultural practices like no-till farming and cover cropping can increase the amount of organic carbon stored in the soil, turning farms into valuable carbon sinks.
- Oceans: Oceans naturally absorb vast amounts of CO 2. "Blue carbon" refers to the carbon captured by coastal ecosystems like mangroves, seagrasses, and salt marshes, which are highly efficient at sequestration.
- Geological Sequestration: This involves engineered technologies, often referred to as Carbon Capture and Storage (CCS).
- Capture: CO 2 is captured from large point sources, such as power plants or industrial facilities, before it can enter the atmosphere.
- Transport: The captured CO 2 is compressed and transported via pipelines or ships.
- Storage: The CO 2 is injected into deep underground geological formations, such as depleted oil and gas reservoirs, deep saline aquifers, or un-minable coal seams, for permanent storage.
Concrete Examples
- Geological Use Case: The Sleipner Project in Norway is one of the world's first and longest-running commercial CCS projects. Since 1996, it has captured CO 2 from natural gas processing and injected approximately one million tonnes per year into a deep saline aquifer beneath the North Sea, preventing it from reaching the atmosphere.
- Biological Use Case: A large-scale reforestation initiative in a degraded region plants millions of native trees. Over decades, this new forest will absorb and store millions of tonnes of CO 2 in its biomass and soil, while also restoring local biodiversity and water cycles. Projects like these can generate carbon credits for the verified amount of CO 2 they sequester.
Understanding these removal mechanisms is crucial for appreciating the full scope of climate action. While sequestration focuses on removing CO 2, market-based mechanisms put a price on the emissions that still occur.
[Learn how carbon markets like the EU ETS create a financial incentive to reduce emissions] and see the official documentation from a leading authority like [the IPCC's Special Report on Carbon Dioxide Capture and Storage].