Carbon Sequestration is the process of capturing and storing carbon (C) in various forms, thereby preventing its release into the atmosphere as greenhouse gases. It is a crucial component of efforts to reduce emissions and combat climate change.
There are two main types of C-Sequestration-
- abiotic, and
Abiotic Carbon Sequestration
involves physical, chemical, and engineering methods that don’t rely on living organisms. This type of sequestration is particularly important because it can capture more carbon. Techniques for abiotic C-Sequestration include:
- Oceanic Injection: CO2 separated from industrial emissions is injected into the deep layers of the ocean to stabilize and reduce its outgassing. This can be done through various methods, such as injecting CO2 into a deep layer, mixing CO2 with saltwater, or discharging it behind a ship.
- Geological Injection: CO2 can be injected into deep layers of minerals and rocks, including coal deposits, old oil wells (to increase productivity), and saline aquifers, which are porous sediment layers containing brackish water.
- Scrubbing and Mineral Carbonation: This process involves transforming CO2 from gases or liquids into inorganic forms like CaCO3 or MgCO3. It includes scrubbing, where CO2 is passed through an absorbent like amine, and mineral carbonation, where the amine-rich CO2 is heated, and CO2 is re-precipitated as carbonate.
Biotic Carbon Sequestrations
involves the management of living organisms, such as plants, animals, and microbes, to reduce carbon emissions and enhance carbon capture. Biotic C-Sequestration techniques include:
- Ocean Fertilization: This method enhances photosynthesis in the ocean, particularly by phytoplankton, which captures atmospheric CO2. Particulate matter produced during this process sinks to the ocean floor, sequestering carbon. Iron (Fe) fertilization can boost phytoplankton activity.
- Soil: Improving soil organic carbon (SOC) and soil inorganic carbon (SIC) can enhance soil C-Sequestration. Techniques include mulching, cover cropping, using organic matter like manure and biochar, and diversifying crops instead of monoculture.
- Forest Land: Forests capture and sequester carbon through the production of lignin and other polyphenol compounds. Wetlands are particularly effective in this case. They can do sequestering about 200 times more carbon than natural vegetation. And it is approximately 1.7±0.5 petagrams of carbon (Pg C) per year!
Biochar is a byproduct of biomass pyrolysis, consisting of carbon and ash. It is known for its ability to retain nutrients, reduce leaching, and improve soil fertility, making it a valuable tool for biotic C-Sequestration.
Overall, C-Sequestration techniques are crucial for mitigating climate change by capturing and storing carbon, preventing its release into the atmosphere, and reducing greenhouse gas emissions.