Carbon capture and storage (CCS) refers to the process by which CO2 released during industrial processes like steel production or power plants is extracted, treated, and then transported for long-term storage sites in deep geological formations like saline aquifers or depleted oil and gas reservoirs – this technology is key in creating a low carbon future.
Trees
Trees absorb carbon from the atmosphere through photosynthesis, the process by which sunlight and water convert into glucose and oxygen molecules, which they store in their trunks, roots, undergrowth and soils before eventually decaying and returning back into the atmosphere. When they die they rot away releasing back their stored sugar molecules back into the environment.
Forests located in temperate climates are excellent at storing carbon. Their trees grow fast, many species being long-lived. Furthermore, decomposition occurs more slowly in these environments compared to tropical ones and their soils can contain up to 50% of total forest carbon stored.
Forest management to increase carbon storage is an integral component of climate solutions, including planting native species, controlling invasive species, harvesting trees for use in durable wood products that last centuries and more – as demonstrated by NFF’s work at Midewin National Tallgrass Prairie and throughout National Forests.
Tropical Forests
Tropical forests are essential carbon sinks, sequestering more carbon than they lose through annual growth and helping to cool the atmosphere by converting solar energy into water vapor that increases sky albedo through cloud formation.
Scientists have undertaken long-term monitoring in permanent sample plots to understand how much carbon trees are capturing and storing – an invaluable way of understanding whether intact forests act as carbon sinks or sources, modulating climate change through climate regulation.
Forest management can also significantly influence carbon capture rates by modulating tree growth and altering soil storage capacities. For instance, thinning forests to promote healthier young trees, and giving them time to regenerate before harvesting can increase their capacity to take in carbon from the air.
However, excessive harvesting or inappropriate methods of thinning forests may disturb the equilibrium between carbon uptake and loss by turning soil into an additional carbon source. To mitigate this issue, using proper techniques and prolonging the thinning cycle may be advantageous.
Soil
Soil is one of Earth’s greatest natural resources, capable of trapping carbon and holding onto it for extended periods. The top metre of global soil contains three times more carbon than exists in its atmosphere, predominantly as bits of organic material such as wood chips, dead plants or animal remains which become stabilized as “soil organic matter” through living organism activity in the soil.
SOM is not only capable of sequestering carbon, but it is also food for various groups of soil microbes that convert it to crop available nutrients or strengthen its resistance against weathering factors that degrade and remove topsoil. Rebuilding or maintaining SOM on agricultural land is crucial to sequestering carbon emissions.
Replenishing and protecting existing soil carbon stores worldwide could offset an estimated 5.5 billion tonnes of greenhouse gases annually, according to research published in Nature Climate Change. This could offset emissions from approximately 1,400 coal-fired power stations each year.
Water
Utilization (CCUS) carbon capture technologies use CO2 capture technology to produce useful products rather than permanently store it underground, potentially mitigating climate impacts depending on which fuels and materials it replaces as well as whether CO2 will then be permanently stored underground. This may help mitigate climate impacts based on fuels replaced and amount of CO2 stored permanently underground.
Some CCUS systems use CO2 injection into oil fields to enhance recovery of existing oil reserves – an example being Terrell Gas Processing Plant in West Texas which has been doing this since 1972.
Water consumption for CO2 capture and storage projects may require substantial amounts, which must be balanced against their climate benefits and considered when choosing a CCS project location. CCS power plant water requirements have been estimated as 87% of their total plant electricity demand when adjusted for net energy production – this figure includes parasitic water demands associated with carbon capture technologies as well as other energy technologies.