Fig 1.
Carbon Accountability Dashboard.
Explanations for each cell are in the Legend (S1 Text). Note that all designations exclude effects of “carbon offsets” or “carbon credits,” which can counteract carbon removal accomplishments [30–35].
Fig 2.
Annual amount of potential CO2 removal by biological methods with improved practices.
With identified improved practices and ecosystem restoration on only 1.5% of US land, CO2 removal could be more than doubled, representing ~40% of US emissions. 1) Biological net sequestration refers to net uptake by plant growth minus emissions from respiration, harvesting, fire, etc. Biological methods included here are forest management, reforestation, regenerative agriculture, wetlands management and restoration. 2) 0.02 Gt represents gross capture per year at emissions sources according to the Global CCS Institute, but excludes emissions from CO2 capture process itself and from EOR oil production, transport, refining and combustion. Also note that all U.S. commercial capture is point-source capture, meaning no CO2 is being removed from the atmosphere (see S1 Data).
Fig 3.
Amount of U.S. land required to achieve an additional net sequestration of 1 Gt CO2/yr with biological methods.
Sequestering 1 Gt CO2/yr (in addition to the 0.9 Gt being sequestered currently by biological methods) could be done by reforestation on only 1.5% of U.S. land in combination with improved practices on existing land (see S1 Data).
Fig 4.
Amount of U.S. land required to achieve 1 Gt CO2/yr removal with biological methods vs solar-powered DAC.
Solar-powered DAC could use as much land as biological methods to remove and store 1 GT CO2/yr. Biological methods would require 33 Macres to sequester 1 Gt additional CO2/yr (see S1 Data). 34.3 Macres could be required for solar-powered DAC (liquid solvent system) — 14.5 million acres for solar arrays and capture facilities [15], and 19.8 million acres for pipelines to transport ½ Gt CO2 to storage sites (based on a 50 ft. right of way for pipelines and a volume calculation based on current oil capacity of 21 Mbbl/day and the daily equivalent for a 1GtCO2/yr sequestration at 27.4Mbbl/day). This assumes that facilities for capture of ½ GtCO2/yr can be sited directly above geologic storage sites so no pipeline transport would be required.
Table 1.
Comparison of the financial cost of mechanical and biological methods of CDR.
Table 2.
Global CO2 removal and sequestration/yr: Biological CDR and DACCS.