Carbon Removal Solutions
Negative emissions approaches can include use of natural systems (e.g., forest/ecosystem restoration, agricultural soil carbon sequestration) and technological systems (e.g. bioenergy with or without direct air capture coupled with storage in long-lived materials, geologic formations, or accelerated CO2 mineralization processes).
Forests (and wetlands):
Forests contain the equivalent of 2,000Gt CO2 and cover some 4 billion hectares of land globally (roughly 30 percent of total land) (FAO 2015). Negative-emissions forest approaches can include forest and wetland restoration, afforestation (i.e., conversion of ecosystems to new forests), and implementation of management techniques that increase carbon sequestration in existing forests.
Numerous farm management techniques offer the potential to increase soil and biomass carbon sequestration in agricultural operations. (Toensmeier 2016). Major “carbon farming” approaches include:
- Livestock: practices such as adaptive management and compost application are informed by ecology to encourage greater forage density and soil buildup
- Crops: techniques such as cover cropping, polycultures, and advanced breeding (for enhancing root growth, turning annual crops into perennials)
- Agroforestry: integrating trees into farm operations
- Biochar: integrating charcoal into agricultural soils
Energy/Industry (including manufacturing and mining):
“Renewable CCS” systems involve two key components: capture from an atmospheric CO2 source and long-term CO2 storage. Capture from an atmospheric CO2 source, instead of from a fossil CO2 source like a coal- or gas-fired power plant or factory, involves (1) direct air capture (DAC) systems that capture CO2 from ambient air using sorbent laden filters and clean energy or (2) biomass energy (including for fuels, power, and other industrial uses), which harnesses the power of photosynthesis to capture CO2 from the atmosphere. Long-term storage, instead of use for short-lived fuel or chemical production involves long-lived materials (e.g., cements and plastics) or rocks, for example, saline aquifers and other porous rock formations, or accelerated mineralization of CO2-reactive rocks.