9 methods to remove carbon from the atmosphere
Carbon removal refers to the process of actively removing carbon dioxide (CO₂) from the atmosphere and storing it in a stable form. There are several methods of carbon removal, including:
Reforestation and afforestation: These methods involve planting trees or other vegetation that absorb CO₂ as they grow. This carbon is then stored in the trees and soil. Reforestation involves planting trees in areas that previously had forests, while afforestation involves planting trees in areas that were previously not forested. Pros: These methods are relatively cheap and easy to implement, and they can also provide additional benefits such as habitat restoration and erosion control. Cons: These methods can take decades to sequester significant amounts of carbon, and the carbon storage may be lost if the trees are cut down or die.
Soil carbon sequestration: This method involves improving soil health and increasing the amount of carbon stored in the soil through practices such as cover cropping, conservation tillage, and composting. Pros: Soil carbon sequestration can be integrated into existing agricultural practices, and it can also improve soil health and productivity. Cons: It can be difficult to measure and verify the amount of carbon stored in the soil.
Direct air capture: This method involves using machines to capture CO₂ directly from the air and storing it in a liquid or solid form. Pros: Direct air capture can remove CO₂ from the atmosphere at a large scale and is not limited to a specific location. Cons: This method is currently expensive and energy-intensive, although costs are expected to decrease as the technology improves.
Carbon capture and storage (CCS): This method involves capturing CO₂ emissions from power plants or other industrial sources and storing them underground. Pros: CCS can significantly reduce CO₂ emissions from large industrial sources. Cons: This method requires significant infrastructure and is only applicable to a limited number of emission sources.
Bioenergy with carbon capture and storage (BECCS): This method involves capturing CO₂ emissions from the burning of biomass and storing them underground. Pros: BECCS can be used to generate electricity while also removing CO₂ from the atmosphere. Cons: BECCS requires a significant amount of land and water, and it may compete with food production. In addition, the long-term stability of the carbon storage is uncertain.
Enhanced weathering: This method involves spreading minerals that react with CO₂ on the surface of the earth, where they absorb CO₂ from the air and convert it into a stable form. Pros: Enhanced weathering can be implemented at a large scale and has the potential to remove significant amounts of CO₂ from the atmosphere. Cons: The long-term stability of the carbon storage is uncertain, and it is unclear how the spread of minerals would impact ecosystems.
Bio-oil: This method involves converting biomass into a liquid fuel that can be stored and used for energy generation. The CO₂ emissions from the burning of the bio-oil are then captured and stored underground. Pros: Bio-oil can be used as a substitute for fossil fuels, and it can also be used to power vehicles. Cons: Bio-oil production requires a significant amount of land and water, and it may compete with food production. The long-term stability of the carbon storage is also uncertain.
Biochar: This method involves converting biomass into a stable, carbon-rich solid that can be stored in the soil. Pros: Biochar can improve soil health and productivity, and it can also be used as a substitute for fossil fuels. Cons: The long-term stability of carbon storage is uncertain, and it is unclear how the use of biochar would impact ecosystems.
It is important to note that no single carbon removal method is perfect, and each has its own set of strengths and limitations. To maximize the effectiveness of carbon removal efforts, it may be necessary to use a combination of different methods.
References:
IPCC (2018). "Summary for Policymakers." In: Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty. Geneva, Switzerland: The Intergovernmental Panel on Climate Change (IPCC).
Smith, P., Davis, S.J., Creutzig, F., Fuss, S., Minx, J.C., Gabrielle, B., Kato, E., Jackson, R.B., Cowie, A., Kriegler, E., et al. (2018). "Negative emissions—Part 2: Costs, potentials and side effects." Environmental Research Letters, 13(11), 113001.
