The technological and economic prospects for CO2 utilization and removal

In the paper

“Previous reviews 18,28,[52][53][54] have shown that these pathways offer substantial CO 2 removal potential:”

What the sources say

• Partly supported

  The Global resource implications of NETs deployment section estimates gigatonne-scale CO₂ removal for technologies including BECCS, supporting substantial removal potential. But the review assesses negative-emissions technologies, not the cited sentence’s specific category of “non-conventional utilization pathways”; our copy does not establish that those pathways have the stated potential. (LLM, conf=0.82)

  cites [18] Smith, P. et al. Biophysical and economic limits to negative CO2 emissions. Nat. Clim. Change 6, 42–50 (2016). This paper quantifies potential global impacts of various negative emissions technologies in the context of biophysical resource constraints. sourceExperimental — accuracy not yet measured
• Disputed

  Section 3.8 (page not provided) discusses CO₂ utilization pathways but raises doubts that they can contribute much to large-scale negative emissions. It also reports a concern that chemical conversion is highly unlikely to provide more than 1% of the mitigation needed for the Paris temperature goal, contrary to the claim of substantial removal potential. (LLM, conf=0.87)

  Checked by a reasoning model — may be wrong.

  cites [28] Fuss, S. et al. Negative emissions—Part 2: Costs, potentials and side effects. Environ. Res. Lett. 13, 063002 (2018). This paper estimates—through a large scoping review—that afforestation and reforestation, BECCS, biochar, enhanced weathering, DACCS and soil carbon sequestration all have multi-gigatonne sequestration potentials in 2050, and that costs vary widely. sourceExperimental — accuracy not yet measured
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [52][53][54]

In the paper

“In the short term, the creation of products from concentrated CO 2 , as in step L (albeit, CO 2 conversion is not a necessary requirement for utilization), could leverage the industrial capture of flue gases following the extraction and combustion of fossil fuels (KC) 27 .”

What the sources say

• Partly supported

  The Short-term scenarios section says near-term CO2 product demand could be met by capturing high-purity emissions, including those from natural gas production. The Conclusions and perspectives section also describes recovered industrial CO2 as a feedstock for consumer goods. But the paper associates capture from coal-fired power plants with longer-term, larger-scale scenarios, rather than the short-term pathway the claim suggests. (LLM, conf=0.84)

  cites [27] Naims, H. Economics of carbon dioxide capture and utilization—a supply and demand perspective. Environ. Sci. Pollut. Res. 23, 22226–22241 (2016). This paper analyses CO 2 supply and demand scenarios to conclude that the business case for CO 2 utilization is technology-specific. sourceExperimental — accuracy not yet measured

In the paper

“For instance, perverse indirect effects-such as land-use change resulting from BECCS 14 -could increase net atmospheric CO 2 concentrations.”

What the sources say

• Supported

  The Abstract says carbon removed through BECCS could be offset by losses from land-use change. The Discussion adds that replacing high-carbon ecosystems with bioenergy crops could result in a negative carbon balance, supporting the claim that BECCS-related land-use change could increase net atmospheric CO₂. (LLM, conf=0.89)

  cites [14] Harper, A. B. et al. Land-use emissions play a critical role in land-based mitigation for Paris climate targets. Nat. Commun. 9, 2938 (2018). source

In the paper

“Some are commercialized 29 , such as the production of urea 30 and polycarbonate polyols 31 .”

What the sources say

• Supported

  The Introduction states that a handful of commercial processes use CO2 as a feedstock, directly supporting the statement attributed to this source. The examples of urea and polycarbonate polyols have separate citations in the citing sentence and are not attributed to this paper here. (LLM, conf=0.93)

  cites [29] Otto, A., Grube, T., Schiebahn, S. & Stolten, D. Closing the loop: captured CO2 as a feedstock in the chemical industry. Energy Environ. Sci. 8, 3283–3297 (2015). source
• Supported

  The paper supports the urea example: its Nomenclature section says CO2 is used as a feedstock for urea and lists several commercialized urea-production processes. In the citing sentence, polycarbonate polyols have a separate citation and are not attributed to this source. (LLM, conf=0.91)

  cites [30] Pérez-Fortes, M., Bocin-Dumitriu, A. & Tzimas, E. CO2 utilization pathways: Techno-economic assessment and market opportunities. Energy Procedia 63, 7968–7975 (2014). source
• ?Not checked — no full text of the sourcecites [31] Langanke, J. et al. Carbon dioxide (CO2) as sustainable feedstock for polyurethane production. Green Chem. 16, 1865–1870 (2014). source

In the paper

“Such products have lifespans of decades or even centuries 36 .”

What the sources say

• Partly supported

  The Results and Discussion section (page unavailable) models product lifetimes ranging from less than a year for packaging to decades for building and construction plastics. It does not establish that products remain in use for centuries; the paper’s discussion of plastics persisting after disposal is distinct from product lifespan. (LLM, conf=0.87)

  cites [36] Geyer, R., Jambeck, J. R. & Law, K. L. Production, use, and fate of all plastics ever made. Sci. Adv. 3, e1700782 (2017). sourceExperimental — accuracy not yet measured

In the paper

“Although the production of more complex hydrocarbons is energetically and therefore economically expensive 11”

What the sources say

• Supported

  In “What should we make using CO2?” (p. 2), the paper says that reducing CO2 to higher-carbon products has a substantial energy cost and that more complex products generally require higher overpotentials. It links energy efficiency and product selectivity to economic viability (pp. 2–3), supporting the claim in the context of CO2 conversion. (LLM, conf=0.91)

  cites [11] Bushuyev, O. S. et al. What should we make with CO2 and how can we make it? Joule 2, 825–832 (2018). source

In the paper

“Increasing urea production may therefore have a negative impact on climate 35 .”

What the sources say

• Partly supported

  The Introduction links nitrous oxide emissions to global warming, and the Abstract reports that applying urea to New Zealand pasture generally increased those emissions. This supports a potential climate impact from increased urea use, but the paper does not assess the impact of increasing urea production itself. (LLM, conf=0.85)

  cites [35] Luo, J., Ledgard, S. & Lindsey, S. Nitrous oxide emissions from application of urea on New Zealand pasture. N. Z. J. Agric. Res. 50, 1–11 (2007). sourceExperimental — accuracy not yet measured

In the paper

“Some are technically possible but are not widely adopted, such as the production of CO 2 -derived methanol in the absence of carbon monoxide 32”

What the sources say

• Partly supported

  The “Roadmap from Fossilized Sunshine to Liquid Sunshine” section describes methanol production from captured CO₂ and says the first commercial deployment of this green-methanol technology could be expected in 2040, supporting that it was not widely deployed. The “5G Liquid Sunshine: Green Alcohol Production” section describes CO₂ hydrogenation approaches, but neither passage establishes production in the absence of carbon monoxide. (LLM, conf=0.83)

  cites [32] Shih, C. F., Zhang, T., Li, J. & Bai, C. Powering the future with liquid sunshine. Joule, 2, 1925–1949 (2018). sourceExperimental — accuracy not yet measured

In the paper

“In recent years, several wind and solar power auctions around the world have been won with prices below 41 $0.03 kWh -1 .”

What the sources say

• Partly supported

  In “Pathways toward industrial implementation” (page not supplied), the paper reports recent onshore wind auctions in several countries with costs as low as $0.03/kWh. It does not report solar auctions at that price, and “as low as” $0.03/kWh does not establish prices below it. (LLM, conf=0.88)

  cites [41] De Luna, P. et al. What would it take for renewably powered electrosynthesis to displace petrochemical processes? Science 364, eaav3506 (2019). This paper reviews the potential for and costs of using renewable energy for electrochemical conversion of concentrated CO 2 into formic acid, carbon monoxide, ethylene and ethanol, and compares biocatalytic and Fischer–Tropsch routes to long-chain chemical production. sourceExperimental — accuracy not yet measured

In the paper

“The flux of carbon from fossil fuels and industry to the atmosphere (34 Gt CO 2 yr -1 ) 15 is dwarfed by the gross flux to land via photosynthesis in plants (440 Gt CO 2 yr -1 ) 16 .”

What the sources say

• ?Could not verify

  The citation is attached to the 440 Gt CO2 yr−1 gross photosynthetic flux. The Figure 2 caption (section 2.8.3, p. 19) says that natural-cycle fluxes appear in the figure, but our copy contains only an image placeholder, not its values. Searches for photosynthesis, gross primary production, 120 GtC yr−1, and 440 Gt CO2 yr−1 found no passage stating the claimed flux. (LLM, conf=0.72)

  cites [15] Le Quéré, C. et al. Global carbon budget 2018. Earth Syst. Sci. Data 10, 2141–2194 (2018). sourceExperimental — accuracy not yet measured
• Not checked yetcites [16] IPCC Climate Change 2014: Mitigation of Climate Change (eds. Edenhofer, O. et al.) (Cambridge Univ. Press, 2014).

In the paper

“In the current market structure, around 60% of plastics have applications in sectors other than packaging-including as durable materials for construction, household goods, electronics, and in vehicles.”

What the sources say

• Partly supported

  The Results and Discussion report that 42% of primary nonfiber plastics produced in 2015 entered use as packaging, implying about 58% entered other sectors; they also identify construction as a major use. The figure is for primary nonfiber plastics, not all plastics, and the passages do not identify household goods, electronics, or vehicles as examples. (LLM, conf=0.85)

  cites [36] Geyer, R., Jambeck, J. R. & Law, K. L. Production, use, and fate of all plastics ever made. Sci. Adv. 3, e1700782 (2017). sourceExperimental — accuracy not yet measured

In the paper

“Such fuels could also find a role in sectors that are harder to decarbonize, such as aviation 39 , since hydrocarbons have energy densities that are orders of magnitude above those of present-day batteries 32 .”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [39] National Academies of Sciences, Engineering, and Medicine. Commercial Aircraft Propulsion and Energy Systems Research: Reducing Global Carbon Emissions (National Academies Press, 2016).
• Partly supported

  The “Supply Chain: Short-and Long-Term Storage” section says liquid energy carriers have energy densities typically 10–50 times those of batteries, supporting the comparison but not the claim of multiple orders of magnitude. The “Roadmap from Fossilized Sunshine to Liquid Sunshine” section discusses CO2-derived alcohol fuels; the passages found do not address their use in aviation. Page numbers were not available in our copy. (LLM, conf=0.85)

  cites [32] Shih, C. F., Zhang, T., Li, J. & Bai, C. Powering the future with liquid sunshine. Joule, 2, 1925–1949 (2018). sourceExperimental — accuracy not yet measured

In the paper

“For pathways that have high capital costs, the benefits of economies of scale and learning could be considerable 42 .”

What the sources say

• Partly supported

  Section 5.5 links sensitivity to capital costs with the importance of economies of scale, and the Conclusions report substantially lower production costs for a larger CCU fuel plant. The paper does not establish benefits from learning, and its analysis concerns the evaluated CCU pathways rather than high-capital-cost pathways generally. (LLM, conf=0.86)

  cites [42] Dimitriou, I. et al. Carbon dioxide utilisation for production of transport fuels: process and economic analysis. Energy Environ. Sci. 8, 1775–1789 (2015). sourceExperimental — accuracy not yet measured

In the paper

“a recent substantive scoping review 28 gives values of 0.5 to 3.6 Gt CO 2 yr -1 for afforestation/ reforestation,”

What the sources say

• Supported

  In the “Global sequestration potentials and costs” section (page unavailable), the review reports a lower-end afforestation/reforestation estimate of 0.54 Gt CO₂ yr⁻¹ and, in its authors’ assessment, approximately 3.6 Gt CO₂ yr⁻¹ under a 500 Mha land constraint. These support the cited approximate values, though they refer to different years and assumptions rather than a single uniform range. (LLM, conf=0.86)

  cites [28] Fuss, S. et al. Negative emissions—Part 2: Costs, potentials and side effects. Environ. Res. Lett. 13, 063002 (2018). This paper estimates—through a large scoping review—that afforestation and reforestation, BECCS, biochar, enhanced weathering, DACCS and soil carbon sequestration all have multi-gigatonne sequestration potentials in 2050, and that costs vary widely. source

In the paper

“Life-cycle analyses on some industrial CO 2 utilization pathways suggest that the potential for net emission reductions is much larger than for net removals, which appears very modest 94 .”

What the sources say

• Partly supported

  The Conclusions report life-cycle emissions reductions for several CO₂-utilisation pathways, while the Introduction says chemical demand has little capacity to sequester CO₂ and that fuel production delays emissions rather than removing them. The paper does not directly compare the overall potential for net emissions reductions with the potential for net removals, so the claimed relative magnitude is an inference. (LLM, conf=0.84)

  cites [94] Cuéllar-Franca, R. M. & Azapagic, A. Carbon capture, storage and utilisation technologies: a critical analysis and comparison of their life cycle environmental impacts. J. CO 2 Utilization 9, 82–102 (2015). This paper compares the environmental impacts of CO 2 utilization and CCS technologies by reviewing the literature of life cycle assessment studies. sourceExperimental — accuracy not yet measured

In the paper

“and 0.5 to 5 Gt CO 2 yr -1 for BECCS.”

What the sources say

• Supported

  The Authors’ assessment gives a BECCS potential range of 0.5–5 Gt CO₂ by 2050. It describes this as a technological potential that accounts for sustainability aims; the citing sentence omits the 2050 context but accurately reports the review’s range. (LLM, conf=0.92)

  cites [28] Fuss, S. et al. Negative emissions—Part 2: Costs, potentials and side effects. Environ. Res. Lett. 13, 063002 (2018). This paper estimates—through a large scoping review—that afforestation and reforestation, BECCS, biochar, enhanced weathering, DACCS and soil carbon sequestration all have multi-gigatonne sequestration potentials in 2050, and that costs vary widely. source

In the paper

“Although several cost estimates exist in the literature-for example, around $200 per tonne of CO 2 28 -these typically assign all costs to the CO 2 removal service, and thus implicitly assume that no revenue is received for the bioenergy services that are generated.”

What the sources say

• Partly supported

  The BECCS costs discussion reports estimates reaching about US$200 per tonne of CO₂, supporting the cited cost example. It does not say that estimates typically assign all costs to CO₂ removal or assume no revenue from bioenergy services; those accounting claims are unsupported by our copy. (LLM, conf=0.84)

  cites [28] Fuss, S. et al. Negative emissions—Part 2: Costs, potentials and side effects. Environ. Res. Lett. 13, 063002 (2018). This paper estimates—through a large scoping review—that afforestation and reforestation, BECCS, biochar, enhanced weathering, DACCS and soil carbon sequestration all have multi-gigatonne sequestration potentials in 2050, and that costs vary widely. sourceExperimental — accuracy not yet measured

In the paper

“The use of terrestrial enhanced weathering on croplands could increase crop yields 28 .”

What the sources say

• Supported

  Section 3.4 says enhanced weathering can supply nutrients and potentially increase biomass production, and it discusses application on cropland. That supports the claim's cautious wording, although the paper notes that field studies quantifying the increase are scarce. (LLM, conf=0.84)

  cites [28] Fuss, S. et al. Negative emissions—Part 2: Costs, potentials and side effects. Environ. Res. Lett. 13, 063002 (2018). This paper estimates—through a large scoping review—that afforestation and reforestation, BECCS, biochar, enhanced weathering, DACCS and soil carbon sequestration all have multi-gigatonne sequestration potentials in 2050, and that costs vary widely. source

In the paper

“This yield enhancement is unlikely to originate directly from increases in soil carbon, but from nutrient uptake that is facilitated by pH effects 57 .”

What the sources say

• Partly supported

  In “Crop production and protection” (page unavailable), the paper says that reversing soil acidification improves nutrient uptake and crop yields, supporting the pH-related mechanism. But “Rocks for food and soil security” says increased soil organic carbon benefits yields and that the long-term carbon effects of applying silicate rocks remain unknown. It does not establish that soil-carbon increases are unlikely to contribute directly to the yield enhancement. (LLM, conf=0.87)

  cites [57] Beerling, D. J. et al. Farming with crops and rocks to address global climate, food and soil security. Nat. Plants 4, 138–147 (2018). sourceExperimental — accuracy not yet measured

In the paper

“2.3 to 5.3 Gt CO 2 yr -1 for land management,”

What the sources say

• Partly supported

  The authors’ assessment in the soil carbon sequestration section gives a realistic technical potential of 3.8 (2.3–5.3) Gt CO₂ yr⁻¹ for 2050. The number matches, but it is an estimate for soil carbon sequestration specifically, not for land management as a whole. (LLM, conf=0.86)

  cites [28] Fuss, S. et al. Negative emissions—Part 2: Costs, potentials and side effects. Environ. Res. Lett. 13, 063002 (2018). This paper estimates—through a large scoping review—that afforestation and reforestation, BECCS, biochar, enhanced weathering, DACCS and soil carbon sequestration all have multi-gigatonne sequestration potentials in 2050, and that costs vary widely. sourceExperimental — accuracy not yet measured

In the paper

“0.3 to 2 Gt CO 2 yr -1 for biochar,”

What the sources say

• Supported

  In the biochar discussion under “Permanence and saturation,” the authors assess a range of 0.3–2 GtCO₂ yr⁻¹ as plausible by 2050. That directly supports the attributed removal-potential figure, with the qualification that it is a plausible estimate for 2050. (LLM, conf=0.91)

  cites [28] Fuss, S. et al. Negative emissions—Part 2: Costs, potentials and side effects. Environ. Res. Lett. 13, 063002 (2018). This paper estimates—through a large scoping review—that afforestation and reforestation, BECCS, biochar, enhanced weathering, DACCS and soil carbon sequestration all have multi-gigatonne sequestration potentials in 2050, and that costs vary widely. source

In the paper

“Conversely, in an economy with high supply-chain emissions, the climate benefit from BECCS is low 72 .”

What the sources say

• Partly supported

  Section 3.5 says biomass supply-chain emissions can offset a BECCS plant’s carbon negativity, supporting the claim that such emissions reduce its climate benefit. But the paper assesses BECCS supply chains, not economies with high supply-chain emissions generally, and its Conclusion says BECCS can still deliver net CO₂ removal under suitable conditions. (LLM, conf=0.84)

  cites [72] Fajardy, M. & Mac Dowell, N. Can BECCS deliver sustainable and resource efficient negative emissions? Energy Environ. Sci. 10, 1389–1426 (2017). sourceExperimental — accuracy not yet measured

In the paper

“Wood products have potential as long-term stores of carbonparticularly when used in long-lived buildings, the lifespans of which can be conservatively estimated at 80-100 years 59 .”

What the sources say

• Partly supported

  The ‘Life cycle forest, product & integrated processing energy carbon pools’ section describes wood in housing and similar buildings as long-lived carbon storage and estimates a useful life of 80 years for US housing. It also says newer housing may last more than 80 years, but it does not give a 100-year upper estimate or call the 80–100-year range conservative. (LLM, conf=0.86)

  cites [59] Lippke, B. et al. Life cycle impacts of forest management and wood utilization on carbon mitigation: knowns and unknowns. Carbon Manage. 2, 303–333 (2011). sourceExperimental — accuracy not yet measured

In the paper

“Impacts on yield are likely to be highly variable-for example, according to climatic zone 64 .”

What the sources say

• Supported

  The Introduction says global averages may conceal important geographical variation in biochar’s effect on yield. The Abstract reports no average yield effect in temperate latitudes but a 25% average increase in the tropics. Page numbers are not provided in our copy. (LLM, conf=0.94)

  cites [64] Jeffery, S. et al. Biochar boosts tropical but not temperate crop yields. Environ. Res. Lett. 12, (2017). source

In the paper

“The net climate impact of the CO 2 utilization pathways will, in many cases, depend upon the emissions intensity from the prevailing processes 73 .”

What the sources say

• Supported

  The Results section defines mitigation as the difference between emissions from conventional production and CCU production, and says reductions come from replacing emission-intensive processes. The paper also reports that CCU’s mitigation potential depends on the carbon footprint of the electricity used. Together, these passages support the claim that the net impact depends on the emissions intensity of the processes involved. (LLM, conf=0.88)

  cites [73] Kätelhön, A., Meys, R., Deutz, S., Suh, S. & Bardow, A. Climate change mitigation potential of carbon capture and utilization in the chemical industry. Proc. Natl Acad. Sci. USA 116, 11187–11194 (2019). source

In the paper

“In terms of the climate impact per kWh of electricity use, available renewable electricity is more efficiently directed towards e-mobility and heat pumps rather than towards hydrogen-based CCU technologies in the chemical industry 73 .”

What the sources say

• Supported

  The Discussion states that e-mobility and heat pumps reduce climate impact more per kilowatt hour of electricity than all hydrogen-based CCU technologies considered in the study. It recommends prioritizing them when limited low-carbon electricity is allocated among competing on-grid uses. (LLM, conf=0.95)

  cites [73] Kätelhön, A., Meys, R., Deutz, S., Suh, S. & Bardow, A. Climate change mitigation potential of carbon capture and utilization in the chemical industry. Proc. Natl Acad. Sci. USA 116, 11187–11194 (2019). source

In the paper

“BECCS has a range of well-articulated risks, including considerable increases in emissions as a result of land-use change 72 .”

What the sources say

• Supported

  In the analysis of direct and indirect land-use change (section 3.3.1.1, p. 1401), the paper reports that adding indirect land-use change can make the biomass supply chain’s overall carbon footprint up to three times higher than in the base case. Section 3.5 also reports reduced BECCS carbon efficiency when land-use changes are included. (LLM, conf=0.93)

  cites [72] Fajardy, M. & Mac Dowell, N. Can BECCS deliver sustainable and resource efficient negative emissions? Energy Environ. Sci. 10, 1389–1426 (2017). source

In the paper

“These estimates are based on currently reported yield increases (of 0.9% to 2% associated with soil carbon sequestration techniques 61,62 and 10% associated with biochar 63 ) from sparse literature, using crop production as a proxy for net primary productivity.”

What the sources say

• ?Not checked — no full text of the sourcecites [61] Lal, R. Enhancing crop yields in the developing countries through restoration of the soil organic carbon pool in agricultural lands. Land Degrad. Dev. 17, 197–209 (2006). source
• Partly supported

  Section 3.3 reports that, across 32 studies in developing countries, a 1.3% annual increase in grain yield was associated with a 0.4% annual increase in soil organic carbon. This supports an association between soil-carbon gains and higher yields, but the paper does not report the cited 0.9%–2% range. Section 3.4 does not support a 10% yield increase from biochar; it notes that yield reductions have sometimes occurred. (LLM, conf=0.85)

  cites [62] Soussana, J.-F. et al. Matching policy and science: Rationale for the ‘4 per 1000-soils for food security and climate’ initiative. Soil Tillage Res. 188, 3–15 (2019). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [63] Jeffery, S., Verheijen, F. G., Van Der Velde, M. & Bastos, A. C. A quantitative review of the effects of biochar application to soils on crop productivity using meta-analysis. Agric. Ecosyst. Environ. 144, 175–187 (2011). source

In the paper

“A major challenge is to improve variations in yield effects, which are likely to hinder the economic decision made by farmers to apply biochar 86 ,”

What the sources say

• Supported

  The 'Defining the agronomic benefit(s) of biochar' section says inconsistent field-trial results are a major contributor to variation in cost-benefit estimates. The 'Biochar application rate' section adds that variable yield responses make economic assessments tentative. Together, these support the claim that uncertain yield effects complicate decisions about investing in biochar; the supplied copy gives no page numbers. (LLM, conf=0.87)

  cites [86] Dickinson, D. et al. Cost-benefit analysis of using biochar to improve cereals agriculture. Glob. Change Biol. Bioenergy 7, 850–864 (2015). source

In the paper

“We also estimate that between 0.2 and 3.2 Gt CO 2 yr -1 could be removed and stored in the lithosphere or in the biosphere for centuries or more.”

In the paper

“Dependent on a multitude of technological, policy and economic factors that remain unresolved, each of the conventional pathways-chemicals, fuels, microalgae, building materials and CO 2 -EOR-might utilize around 0.5 Gt CO 2 yr -1 or more in 2050.”

In the paper

“however, the permanence of CO 2 storage varies greatly from one utilization pathway to another, with storage timeframes ranging from days to millennia.”

In the paper

“Breakeven costs per tonne of CO 2 , calculated from the scoping review, for urea (around -$100) and for polyols (around -$2,600) reflect that these markets are currently profitable.”

In the paper

“The estimated potential for the scale of CO 2 utilization in fuels varies widely, from 1 to 4.2 Gt CO 2 yr -1 , reflecting uncertainties in potential market penetration.”

In the paper

“The interquartile range for breakeven costs for CO 2 fuels from our scoping review was $0 to $670 per tonne of CO 2 .”

In the paper

“Our assessment suggests that each pathway could scale to over 0.5 gigatonnes of carbon dioxide utilization annually.”

In the paper

“Of the ten pathways we discuss, five leverage our ability to perturb these land-based fluxes.”

In the paper

“For the production of polymers, the utilization potential of CO 2 is estimated to be 10 to 50 Mt yr -1 in 2050.”

In the paper

“we estimate breakeven costs of between $60 and $160 per tonne of CO 2 utilized.”

In the paper

“breakeven costs of -$30 to $70 per tonne of CO 2.”

In the paper

“Negative breakeven costs appear in studies that model particularly beneficial scenarios, such as low discount rates, free feedstocks, or free or low-cost renewable electricity.”

In the paper

“We estimate that, of the volumes of CO 2 sequestered via afforestation/reforestation in 2050, between 0.07 and 0.5 Gt of the CO 2 utilized per year may flow into industrial roundwood products,”

In the paper

“For instance, obtaining a barrel of oil via CO 2 -EOR utilizes CO 2 , which can remain in the oil formation rather than being re-emitted into the atmosphere.”

In the paper

“We estimate a 2050 utilization rate of around 0.1 to 1.8 Gt CO 2 yr -1 .”

In the paper

“Some CO 2 utilization pathways involve chemical transformations that require the input of substantial amounts of energy (Supplementary Fig. 2).”

In the paper

“The remainder of the carbon in the wood-product pool will return to the atmosphere as a fraction (about 0.5 Gt CO 2 yr -1 ) of the 5 Gt CO 2 yr -1 land-use change flux that is depicted in Fig. 1.”

In the paper

“at approximate breakeven costs of between -$70 and -$60 per tonne of CO 2 utilized.”

In the paper

“at approximate breakeven costs of between -$40 and $10 per tonne of CO 2 utilized.”

In the paper

“Of these, 0.6 Gt CO 2 may arise from the portion of those flows that are industrial roundwood products sustainably harvested for use in the construction industry (Supplementary Materials);”

In the paper

“The specific assumptions of the low scenario, which do not account for potential overlaps in utilization volumes between pathways, imply an upper bound of over 1.5 Gt CO 2 yr -1 at well under $100 per tonne of CO 2 utilized.”

In the paper

“this leads to a top-end estimate of 1.1 Gt CO 2 utilized per year from afforestation/reforestation and sustainable forestry techniques.”

In the paper

“Prices for a fuel product made using CO 2 currently exceed market prices considerably (Table 3).”

In the paper

“We estimate that around 0.9 to 1.9 Gt CO 2 yr -1 may be used by soil carbon sequestration techniques on croplands and grazing lands by 2050;”

In the paper

“We tentatively estimate that approximately 0.2 to 1 Gt CO 2 yr -1 may be utilized via yield increases after the application of biochar on managed lands,”

In the paper

“The four closed pathways, except for CO 2 -EOR, are mainly at low technology readiness levels (TRLs).”

In the paper

“Yearly inflows of carbon used as wood products are estimated to be around 1.8 Gt CO 2 in 2050.”

In the paper

“We estimate that around half of the carbon in the wood-product pool might continue to be stored beyond the usable life of the products”

In the paper

“approximate breakeven costs are estimated at between -$90 and -$20 per tonne of CO 2 utilized, owing to yield increases that are associated with increases in soil organic carbon stock.”

In the paper

“| Methanol | 510 | 400 | +30% | Insufficient consensus | Downward |”

In the paper

“| Dimethyl ether | 2,740 | 660 | +320% | Insufficient consensus | Downward |”

In the paper

“| Aggregates | 21 | 18 | +20% | Insufficient consensus | Downward |”

In the paper

“| Methanol | 510 | 400 | +30% | Insufficient consensus | Downward |”

In the paper

“| Methane | 1,740 | 360 | +380% | Likely to be more expensive | Downward |”

In the paper

“| Aggregates | 21 | 18 | +20% | Insufficient consensus | Downward |”

In the paper

“| Microalgae | 2,680 | 1,000 | +170% | Likely to be more expensive | Insufficient consensus |”

In the paper

“| Methane | 1,740 | 360 | +380% | Likely to be more expensive | Downward |”

In the paper

“| Fischer-Tropsch | 4,160 | 1,200 | +250% | Likely to be more expensive | Downward |”

In the paper

“| Polymers | 1,440 | 2,040 | -30% | Likely to be cheaper | Downward |”

In the paper

“| Methanol | 510 | 400 | +30% | Insufficient consensus | Downward |”

In the paper

“| Cement curing | 56 | 71 | -20% | Likely to be cheaper | Downward |”

In the paper

“| Polymers | 1,440 | 2,040 | -30% | Likely to be cheaper | Downward |”

In the paper

“| Microalgae | 2,680 | 1,000 | +170% | Likely to be more expensive | Insufficient consensus |”

In the paper

“| CO 2 -EOR | n.a. | n.a. | n.a. | Likely to be more expensive | Upward |”

In the paper

“| Methane | 1,740 | 360 | +380% | Likely to be more expensive | Downward |”

In the paper

“| CO 2 -EOR | n.a. | n.a. | n.a. | Likely to be more expensive | Upward |”

In the paper

“| Aggregates | 21 | 18 | +20% | Insufficient consensus | Downward |”

In the paper

“| Fischer-Tropsch | 4,160 | 1,200 | +250% | Likely to be more expensive | Downward |”

In the paper

“For instance, our analysis suggests that closed pathways with scalability-such as BECCS and building materials-would be sensitive to a subsidy for CO 2 removals.”

In the paper

“| Cement curing | 56 | 71 | -20% | Likely to be cheaper | Downward |”

In the paper

“| Cement curing | 56 | 71 | -20% | Likely to be cheaper | Downward |”

In the paper

“| Dimethyl ether | 2,740 | 660 | +320% | Insufficient consensus | Downward |”

In the paper

“| Fischer-Tropsch | 4,160 | 1,200 | +250% | Likely to be more expensive | Downward |”

In the paper

“| Dimethyl ether | 2,740 | 660 | +320% | Insufficient consensus | Downward |”

In the paper

“| Polymers | 1,440 | 2,040 | -30% | Likely to be cheaper | Downward |”

In the paper

“and resource constraints prevent the simultaneous deployment of all pathways.”

In the paper

“For instance, net zero CO 2 -based fuels must shift the current flows of carbon, from a lithosphere-to-atmosphere (KCLG) to an atmosphere-to-atmosphere cycle (ALG) (Fig. 2).”

In the paper

“Furthermore, CCS and CDR can fail to deliver a climate benefit.”

In the paper

“However, barriers to implementation remain substantial”

In the paper

“For CO 2 utilization to contribute usefully to the reduction of atmospheric CO 2 concentrations, the scale of the pathways must be meaningful in comparison with the net flows of CO 2 shown in Fig. 1.”

In the paper

“However, these plants represent special cases that may be difficult to replicate because they are exploiting geographic advantages, such as the availability of cheap geothermal energy.”

In the paper

“Other life-cycle analyses have found neutral or negative impacts of CO 2 utilization on reducing emissions 74,[96][97][98] .”

What the sources say

• ?Not checked — no full text of the sourcecites [74] Jaramillo, P., Griffin, W. M. & McCoy, S. T. Life cycle inventory of CO2 in an enhanced oil recovery system. Environ. Sci. Technol. 43, 8027–8032 (2009). source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [96][97][98]

In the paper

“between 1.1 and 3.3 barrels (bbl) of oil can be produced per tonne of CO 2 injected under conventional operation and within the constraints of natural reservoir heterogeneity 49 .”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [49] Heidug, W. et al. Storing CO 2 through enhanced oil recovery: combining EOR with CO 2 storage (EOR+) for profit. (International Energy Agency, 2015).

In the paper

“If the CO 2 -EOR oil displaces the use of renewable electricity in an electric vehicle, CO 2 -EOR generates a net increase in emissions.”

In the paper

“If EOR was deployed to maximize CO 2 storage-rather than oil output-then genuine CO 2 emission reductions are possible, depending on the emissions intensity of the counterfactual and on the relevant inefficiencies (Box 1).”

In the paper

“However, in principle-and depending on operating conditions and project type-CO 2 -EOR can be operated such that, on a life-cycle basis, more CO 2 is injected than is produced upon consumption of the final oil product 50 .”

What the sources say

• ?Not checked — no full text of the sourcecites [50] Stewart, R. J. & Haszeldine, R. S. Can producing oil store carbon? Greenhouse gas footprint of CO2EOR, offshore North Sea. Environ. Sci. Technol. 49, 5788–5795 (2015). source

In the paper

“Nearly 4 tonnes of CO 2 emissions may be avoided for each tonne of dry wood used that displaces concrete-based materials 95 .”

What the sources say

• ?Not checked — no full text of the sourcecites [95] Sathre, R. & O’Connor, J. Meta-analysis of greenhouse gas displacement factors of wood product substitution. Environ. Sci. Policy 13, 104–114 (2010). source

In the paper

“But various direct and indirect effects over the relevant life cycle must be considered and compared to a plausible baseline or 'counterfactual'-what would have happened without CO 2 utilization 83 .”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [83] Zimmermann, A. et al. Techno-Economic Assessment & Life-Cycle Assessment Guidelines for CO 2 Utilization (Global CO2 Initiative, 2018).

In the paper

“Assiduously calculating direct impacts in one place, and at one time, is of little use if there is a 'waterbed effect' (also referred to as a 'rebound' or 'leakage') in which emissions occur somewhere else, or later.”

In the paper

“In reality, the emissions from the baseline barrel of oil that was displaced by the CO 2 -EOR oil might be higher or lower, depending on its origin and its production process.”

In the paper

“For instance, CO 2 utilization pathways that involve the input of energy from nondecarbonized sources may result in net life-cycle increases in CO 2 96-99 .”

What the sources say

• ?Not checked — no full text of the sourcecites [96] van der Giesen, C., Kleijn, R. & Kramer, G. J. Energy and climate impacts of producing synthetic hydrocarbon fuels from CO2. Environ. Sci. Technol. 48, 7111–7121 (2014). source
• ?Not checked — no full text of the sourcecites [97] Sternberg, A., Jens, C. M. & Bardow, A. Life cycle assessment of CO2-based C1-chemicals. Green Chem. 19, 2244–2259 (2017). source
• ?Not checked — no full text of the sourcecites [98] Abanades, J. C., Rubin, E. S., Mazzotti, M. & Herzog, H. J. On the climate change mitigation potential of CO2 conversion to fuels. Energy Environ. Sci. 10, 2491–2499 (2017). source
• ?Not checked — no full text of the sourcecites [99] Sternberg, A. & Bardow, A. Life cycle assessment of power-to-gas: syngas vs methane. ACS Sustain. Chem. Eng. 4, 4156–4165 (2016). source

In the paper

“More than 90% of the world's oil reservoirs are potentially suitable for CO 2 -EOR 51 ,”

What the sources say

• ?Not checked — no full text of the sourcecites [51] Godec, M. L. Global Technology Roadmap for CCS in Industry: Sectoral Assessment CO 2 Enhanced Oil Recovery. (United Nations Industrial Development Organization, 2011).

In the paper

“which implies that as much as 140 Gt CO 2 could be used and stored in this way 5 .”

What the sources say

• ?Not checked — no full text of the sourcecites [5] Mac Dowell, N., Fennell, P. S., Shah, N. & Maitland, G. C. The role of CO2 capture and utilization in mitigating climate change. Nat. Clim. Change 7, 243–249 (2017). This paper assesses the potential for CO 2-derived fuels and chemicals to be a fraction of that possible via CO 2-EOR. source

In the paper

“As such, unless calcination is paired with carbon capture and sequestration, it is difficult for building-related pathways to deliver reductions in CO 2 emissions on a life-cycle basis.”

In the paper

“New sorbents could reduce the cost of energy-intensive separation of CO 2 from flue gases and industrial streams 40,78 .”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [40] Secretary of Energy Advisory Board. Letter Report: Task Force on RD&D Strategy for CO 2 Utilization and/or Negative Emissions at the Gigatonne Scale. (US Department of Energy, 2016).
• ?Not checked — no full text of the sourcecites [78] Senftle, T. P. & Carter, E. A. The holy grail: chemistry enabling an economically viable CO2 capture, utilization, and storage strategy. Acc. Chem. Res. 50, 472–475 (2017). source

In the paper

“Life-cycle emissions and costs depend upon the source of the energy used.”

In the paper

“The cycling pathways (other than the production of urea and polyols) must compete with lower-cost incumbents.”

In the paper

“Some require energy to increase CO 2 concentrations from 0.04% towards 100% 66 .”

What the sources say

• ?Not checked — no full text of the sourcecites [66] Darton, R. & Yang, A. Removing carbon dioxide from the atmosphere – assessing the technologies. Chem. Eng. Trans. 69, 91–96 (2018). source

In the paper

“The emissions-reduction potentials of the three cycling pathways would be facilitated by declines in the costs of CO 2 capture.”

In the paper

“For instance, CO 2 -EOR might currently contribute to an overall reduction in atmospheric CO 2 , compared to business-as-usual 49 .”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [49] Heidug, W. et al. Storing CO 2 through enhanced oil recovery: combining EOR with CO 2 storage (EOR+) for profit. (International Energy Agency, 2015).

In the paper

“In general, low TRLs will also challenge the ability of pathways to scale rapidly enough and within the desired timeframe for mitigation 5 .”

What the sources say

• ?Not checked — no full text of the sourcecites [5] Mac Dowell, N., Fennell, P. S., Shah, N. & Maitland, G. C. The role of CO2 capture and utilization in mitigating climate change. Nat. Clim. Change 7, 243–249 (2017). This paper assesses the potential for CO 2-derived fuels and chemicals to be a fraction of that possible via CO 2-EOR. source

In the paper

“Much of this potential CO 2 utilizationnotably in 'closed' and 'open' pathways-may be economically viable without substantial shifts in prices.”

In the paper

“biological pathways are not necessarily more expensive.”

In the paper

“Furthermore, land availability means that choosing one land-based pathway (for example, BECCS) might preclude the application of another at scale (for example, biochar).”

In the paper

“As decarbonization proceeds, however, the climate benefit of CO 2 -EOR is reduced.”

In the paper

“In the longer term, cheaper direct air capture (based on clean energy) would support the scale-up of these pathways 79 .”

What the sources say

• ?Not checked — no full text of the sourcecites [79] Keith, D. W., Holmes, G., St., Angelo, D. & Heidel, K. A process for capturing CO2 from the atmosphere. Joule 2, 1573–1594 (2018). source

In the paper

“the non-decomposed fraction of the portion of total wood products that are presently committed to landfill (around 60%) is approximately 77% 60”

What the sources say

• Not checked yetcites [60] FAOSTAT (Food and Agricultural Organization of the United Nations, accessed 10 May 2018); http://fao.org/faostat/en/#data

In the paper

“Our expert opinion survey, which included sources from both academia and industry, reflected great uncertainty about future costs.”

In the paper

“Each of the potentially large-scale, low-cost pathways also face challenges as mitigation strategies.”

In the paper

“Research into materials and catalysts for CO 2 reduction could enable the efficient transformation of CO 2 into a broader range of products at a lower cost 78 .”

What the sources say

• ?Not checked — no full text of the sourcecites [78] Senftle, T. P. & Carter, E. A. The holy grail: chemistry enabling an economically viable CO2 capture, utilization, and storage strategy. Acc. Chem. Res. 50, 472–475 (2017). source