Carbfix

Carbfix was founded by the then Icelandic President, Dr Ólafur Ragnar Grímsson, Einar Gunnlaugsson at Reykjavík Energy, Wallace S. Broecker at Columbia University, Eric H. Oelkers at CNRS Toulouse (France), and Sigurður Reynir Gíslason at the University of Iceland to limit the Greenhouse gas emissions in Iceland.{{cite journal|last1=Gíslason|first1=Sigurður R.|last2=Sigurðardóttir|first2=Holmfriður|last3=Aradóttir|first3=Edda Sif|last4=Oelkers|first4=Eric H.|date=July 2018|title=A brief history of CarbFix: Challenges and victories of the project's pilot phase|journal=Energy Procedia|volume=146|pages=103–114|doi=10.1016/j.egypro.2018.07.014|doi-access=free|bibcode=2018EnPro.146..103G }} Reykjavik Energy supplied the initial funding for Carbfix. Further funding has been supplied by The European Commission and the Department of Energy of the United States. In addition to finding a new method for permanent carbon dioxide storage, another objective of the project was to train scientists.{{Cite news|title=That {{CO2}} warming the world: Lock it in a rock |url=http://www.mercurynews.com/science-headlines/ci_18773956|access-date =11 October 2011}}

File:CarbFix core.png

Captured CO₂ is dissolved in water, either prior to or during injection into mafic or ultramafic formations, such as basalts. The dissolution of CO₂ in water can be expressed as:

CO₂ (g) + H₂O(l) ⇌ H₂CO₃ (aq)

↔ H₃O⁺(aq) + HCO₃^- (aq)

↔ 2H₃O⁺(aq) + CO₃^2-(aq)

By dissolving the CO₂ in water instant solubility trapping is achieved, which is the second most secure trapping mechanism of CO₂ storage:{{Cite web |last1=Benson |first1=S.M. |last2=Cook |first2=P. |last3=Anderson |first3=J. |last4=Bachu |first4=S. |last5=Nimir |first5=H.B. |last6=Basu |first6=B. |last7=Bradshaw |first7=J. |last8=Deguchi |first8=G. |last9=Gale |first9=J. |date=January 2005 |title=Underground Geological Storage, IPCC Special Report on Carbon Dioxide Capture and Storage, Chapter 5 |url=https://www.researchgate.net/publication/264453028 |website=Intergovernmental Panel on Climate Change, Cambridge University Press Cambridge, U.K.}} No CO₂ bubbles are present in the CO₂-charged water, which is furthermore denser than the water that is present in the formation, so that the CO₂-charged water has rather the tendency to sink than to migrate upwards towards the surface.{{Cite journal |last1=Sigfusson |first1=Bergur |last2=Gislason |first2=Sigurdur R. |last3=Matter |first3=Juerg M. |last4=Stute |first4=Martin |last5=Gunnlaugsson |first5=Einar |last6=Gunnarsson |first6=Ingvi |last7=Aradottir |first7=Edda S. |last8=Sigurdardottir |first8=Holmfridur |last9=Mesfin |first9=Kiflom |last10=Alfredsson |first10=Helgi A. |last11=Wolff-Boenisch |first11=Domenik |last12=Arnarsson |first12=Magnus T. |last13=Oelkers |first13=Eric H. |date=June 2015 |title=Solving the carbon-dioxide buoyancy challenge: The design and field testing of a dissolved CO2 injection system |url=https://doi.org/10.1016/j.ijggc.2015.02.022 |journal=International Journal of Greenhouse Gas Control |volume=37 |pages=213–219 |doi=10.1016/j.ijggc.2015.02.022 |issn=1750-5836}}

The CO₂-charged water is acidic, typically having a pH of 3-5 depending on the partial pressure of CO₂, water composition, and the temperature of the system. The CO₂-charged water reacts with the subsurface rocks and dissolves cations such as Calcium, Magnesium, and Iron.{{Cite journal |last1=Gislason |first1=Sigurdur R. |last2=Oelkers |first2=Eric H. |date=2014-04-25 |title=Carbon Storage in Basalt |url=https://www.science.org/doi/10.1126/science.1250828 |journal=Science |language=en |volume=344 |issue=6182 |pages=373–374 |doi=10.1126/science.1250828 |pmid=24763582 |bibcode=2014Sci...344..373G |issn=0036-8075|url-access=subscription }} The dissolution of cation-bearing silicate minerals; for example, the dissolution of pyroxene, a common mineral in basalt and peridotite, can be expressed as:

2H₃O⁺ + (Ca,Mg,Fe)SiO₃ = Ca²⁺, Mg²⁺, Fe²⁺ + H₄SiO₄ + H₂O

The cations can react with the dissolved CO₂ to form stable carbonate minerals, such as Calcite (CaCO₃), Magnesite (MgCO₃), and Siderite (FeCO₃), a reaction that can be expressed as:  

Ca²⁺,Mg²⁺,Fe²⁺(aq) + CO₃^2-(aq) → CaCO₃ (s), MgCO₃ (s), FeCO₃ (s)

Ultramafic and mafic rock formations are most efficient due to their high reactivity and their abundance in divalent metal cations. The degree to which the released cations form minerals depends on the element, the pH and the temperature.

Drilling and injecting carbonated water at high pressure into basaltic rocks at Hellisheiði has been estimated to cost less than $25 per ton of carbon dioxide sequestered.{{cite journal|last1=Gunnarsson|first1=Ingvi|last2=Aradóttir|first2=Edda S.|last3=Oelkers|first3=Eric H.|last4=Clark|first4=Deirdre E.|last5=Arnarson|first5=Magnús Þór|last6=Sigfússon|first6=Bergur|last7=Snæbjörnsdóttir|first7=Sandra Ó.|last8=Matter|first8=Juerg M.|last9=Stute|first9=Martin|last10=Júliusson|first10=Bjarni M.|last11=Gíslason|first11=Sigurður R.|date=December 2018|title=The rapid and cost-effective capture and subsurface mineral storage of carbon and sulfur at the CarbFix2 site|url=https://eprints.soton.ac.uk/425577/1/Gunnarsson_et_al._IJGGC_manuscript_revised.pdf|journal=International Journal of Greenhouse Gas Control|volume=79|pages=117–126|doi=10.1016/j.ijggc.2018.08.014|doi-access=free|bibcode=2018IJGGC..79..117G }}

This project commenced carbon injection in 2012.{{cite journal |last1=Matter |first1=Juerg M. |last2=Stute |first2=Martin |last3=Snæbjörnsdottir |first3=Sandra O. |last4=Oelkers |first4=Eric H. |last5=Gislason |first5=Sigurdur R. |last6=Aradottir |first6=Edda S. |last7=Sigfusson |first7=Bergur |last8=Gunnarsson |first8=Ingvi |last9=Sigurdardottir |first9=Holmfridur |last10=Gunlaugsson |first10=Einar |last11=Axelsson |first11=Gudni |last12=Alfredsson |first12=Helgi A. |last13=Wolff-Boenisch |first13=Domenik |last14=Mesfin |first14=Kiflom |last15=Fernandez de la Reguera Taya |first15=Diana |date=June 10, 2016 |title=Rapid carbon mineralization for permanent disposal of anthropogenic carbon dioxide emissions |journal=Science |volume=352 |issue=6291 |pages=1312–1314 |bibcode=2016Sci...352.1312M |doi=10.1126/science.aad8132 |pmid=27284192 |doi-access=free |last16=Hall |first16=Jennifer |last17=Dideriksen |first17=Knud |last18=Broecker |first18=Wallace S.}}{{Cite web|url=http://grebeproject.eu/2017/02/09/carbfix-project-gas-rock/|title=Carbfix project – from gas to rock - GREBE Project|date=2017-02-19|website=GREBE project, European Union|language=en-US|access-date=2017-12-04}}{{Cite journal|last1=Sigfusson|first1=Bergur|last2=Gíslason|first2=Sigurður R.|last3=Matter|first3=Juerg M.|last4=Stute|first4=Martin|last5=Gunnlaugsson|first5=Einar|last6=Gunnarsson|first6=Ingvi|last7=Aradóttir|first7=Edda S.|last8=Sigurðardóttir|first8=Holmfriður|last9=Mesfin|first9=Kiflom|date=June 2015|title=Solving the carbon-dioxide buoyancy challenge: The design and field testing of a dissolved {{CO2}} injection system|journal=International Journal of Greenhouse Gas Control|volume=37|pages=213–219|last10=Alfredsson|first10=Helgi A.|last11=Wolff-Beonisch|first11=Domenik|last12=Arnarsson|first12=Magnus T.|last13=Oelkers|first13=Eric H.|doi=10.1016/j.ijggc.2015.02.022|doi-access=free}} The funding was supplied by the University of Iceland, Columbia University, France's National Centre of Scientific Research, the United States Department of Energy, the EU, Nordic funds and Reykjavik Energy.{{cite news|title=Iceland's Hellisheidi prepares to start injection at carbon storage project|url=http://www.ifandp.com/article/0013593.html|date=9 September 2011|access-date=2011-09-16|archive-url=https://web.archive.org/web/20120327014804/http://www.ifandp.com/article/0013593.html|archive-date=2012-03-27|url-status=dead}}

These funding sources include the European Union's Horizon 2020 research and innovation programme under grant agreements No. 764760 and 764810. The European Commission through the projects CarbFix (EC coordinated action 283148), Min-GRO (MC-RTN-35488), Delta-Min (PITN-GA-2008-215360), and {{CO2}}-REACT (EC Project 317235). Nordic fund 11029-NORDICCS; the Icelandic GEORG Geothermal Research fund (09-02-001) to S.R.G. and Reykjavik Energy; and the U.S. Department of Energy under award number DE-FE0004847.

Cost is around US$25 per tonne of CO₂.{{Cite web|title=This startup has unlocked a novel way to capture carbon—by turning the dirty gas into rocks|url=https://fortune.com/2021/03/06/carbon-capture-storage-rocks-net-zero-carbfix-startup-iceland/|access-date=2021-12-01|website=Fortune|language=en}}

Reinjection of geothermal fluid from the Hellisheiði Geothermal Power Plant started in Húsmúli reinjection field, in September 2011. Commissioning of the reinjection site caused significant induced seismicity that was felt in nearby communities.{{Cite web |date=2011-09-13 |title=Vatnsdæling veldur skjálftum [English: Water pumping causes tremor] |url=https://www.ruv.is/frettir/innlent/vatnsdaeling-veldur-skjalftum/ |access-date=2024-06-05 |website=RÚV}}{{Cite journal |last1=Juncu |first1=D. |last2=Árnadóttir |first2=Th. |last3=Geirsson |first3=H. |last4=Guðmundsson |first4=G.B. |last5=Lund |first5=B. |last6=Gunnarsson |first6=G. |last7=Hooper |first7=A. |last8=Hreinsdóttir |first8=S. |last9=Michalczewska |first9=K. |date=February 2020 |title=Injection-induced surface deformation and seismicity at the Hellisheidi geothermal field, Iceland |url=https://doi.org/10.1016/j.jvolgeores.2018.03.019 |journal=Journal of Volcanology and Geothermal Research |volume=391 |pages=106337 |doi=10.1016/j.jvolgeores.2018.03.019 |bibcode=2020JVGR..39106337J |issn=0377-0273}} This problem was addressed by introducing a new workflow where preventive steps are taken to minimize this risk, including the adjustment of the injection rates.{{Cite web |last1=Thorsteinsson |first1=H. |last2=Gunnarsson |first2=G. |date=January 2014 |title=Induced seismicity-stakeholder engagement in Iceland |url=https://www.researchgate.net/publication/289289177 |website=GRC Trans. 38, 879–882}} The implementation of the workflow resulted in the decrease of the annual number of seismic events greater than magnitude 2 in the area from 96 in 2011 to one in 2018,{{Cite journal |last1=Pind Aradóttir |first1=Edda Sif |last2=Hjálmarsson |first2=Eiríkur |date=July 2018 |title=CarbFix – public engagement and transparency |journal=Energy Procedia |volume=146 |pages=115–120 |doi=10.1016/j.egypro.2018.07.015 |issn=1876-6102|doi-access=free |bibcode=2018EnPro.146..115P }} which is considered satisfactory and demonstrates that current operations are within regulatory boundaries.

Carbfix started injection of CO₂ captured from the Hellisheiði Geothermal Power Plant and dissolved in condensate from the plant’s turbines into one of the existing reinjection wells in the Húsmúli reinjection field in April 2014.{{Cite journal |last1=Snæbjörnsdóttir |first1=Sandra Ó. |last2=Tómasdóttir |first2=Sigrún |last3=Sigfússon |first3=Bergur |last4=Aradóttir |first4=Edda Sif |last5=Gunnarsson |first5=Gunnar |last6=Niemi |first6=Auli |last7=Basirat |first7=Farzad |last8=Dessirier |first8=Benoît |last9=Gislason |first9=Sigurdur R. |last10=Oelkers |first10=Eric H. |last11=Franzson |first11=Hjalti |date=July 2018 |title=The geology and hydrology of the CarbFix2 site, SW-Iceland |url=https://doi.org/10.1016/j.egypro.2018.07.019 |journal=Energy Procedia |volume=146 |pages=146–157 |doi=10.1016/j.egypro.2018.07.019 |bibcode=2018EnPro.146..146S |issn=1876-6102}} No increased seismicity was noted after the injection of CO₂ started implying that seismicity is not induced by the injection of the condensate-dissolved CO₂.{{Cite book |last1=Hjörleifsdóttir |first1=Vala |last2=Ingvarsson |first2=Garðar |last3=Ratouis |first3=Thomas |last4=Gunnarsson |first4=Gunnar |last5=Snæbjörnsdóttir |first5=Sandra Ósk |last6=Sigfússon |first6=Bergur |chapter=Ten years of induced earthquakes in the Húsmúli CO2 injection site, Hellisheiði, Iceland |date=December 2021 |title=Sixth International Conference on Engineering Geophysics, Virtual, 25–28 October 2021 |chapter-url=https://library.seg.org/doi/10.1190/iceg2021-027.1 |journal=Sixth International Conference on Engineering Geophysics |series=SEG Global Meeting Abstracts |language=en |publisher=Society of Exploration Geophysicists |pages=96–100 |doi=10.1190/iceg2021-027.1}}

File:Hellisheidi Geothermal Power Plant.png

Carbfix is currently operating four injection sites in Iceland with emphasis on injection of CO₂ captured from point-sources of CO₂, CO₂ that is captured and transported to an injection site, and CO₂ that is captured directly from the atmosphere using direct air capture (DAC) technology.{{Cite web |title=Carbfix |url=https://carbfix.com/ |access-date=2024-05-29 |website=carbfix.com |language=en}}

Carbfix has since June 2014 captured and injected CO₂ and hydrogen sulfide (H₂S) from Hellisheiði Geothermal Power Plant. The geothermal gases are dissolved in condensate from the power plant’s turbines in a specially designed scrubbing tower and injected to a depth of 750 m underground into basaltic rocks.{{Cite journal |last1=Ratouis |first1=Thomas M.P. |last2=Snæbjörnsdóttir |first2=Sandra Ó. |last3=Voigt |first3=Martin J. |last4=Sigfússon |first4=Bergur |last5=Gunnarsson |first5=Gunnar |last6=Aradóttir |first6=Edda S. |last7=Hjörleifsdóttir |first7=Vala |date=February 2022 |title=Carbfix 2: A transport model of long-term CO2 and H2S injection into basaltic rocks at Hellisheidi, SW-Iceland |url=https://doi.org/10.1016/j.ijggc.2022.103586 |journal=International Journal of Greenhouse Gas Control |volume=114 |pages=103586 |doi=10.1016/j.ijggc.2022.103586 |issn=1750-5836|url-access=subscription }} Currently about 68% of the H₂S and 34% of the CO₂ from the plant’s emissions are captured and injected, which amounts to about 12,000 tons of CO₂ per year, and about 5,000 tons of H₂S per year. Results show that over 60% of the injected CO₂ was mineralized within 4 months of injection, and over 85% of the injected H₂S within 4 months of injection.{{Cite journal |last1=Clark |first1=Deirdre E. |last2=Oelkers |first2=Eric H. |last3=Gunnarsson |first3=Ingvi |last4=Sigfússon |first4=Bergur |last5=Snæbjörnsdóttir |first5=Sandra Ó. |last6=Aradóttir |first6=Edda S. |last7=Gíslason |first7=Sigurður R. |date=June 2020 |title=CarbFix2: CO2 and H2S mineralization during 3.5 years of continuous injection into basaltic rocks at more than 250 °C |url=https://doi.org/10.1016/j.gca.2020.03.039 |journal=Geochimica et Cosmochimica Acta |volume=279 |pages=45–66 |doi=10.1016/j.gca.2020.03.039 |issn=0016-7037|hdl=20.500.11815/1757 |hdl-access=free }}

Carbfix is currently working on scaling up the operations at the Hellisheiði Geothermal Power Plant through the EU Innovation Fund project Silverstone, aiming for near-zero geothermal power production from 2025 by capturing over 95% of CO₂ and 99% of H₂S from the plant’s emissions. This accounts for up to 40,000 tons of CO₂ and up to 12,000 tons of H₂S per year.{{Cite web |title=Silverstone: mimicking nature's way to transform CO2 into stone - European Commission |url=https://cinea.ec.europa.eu/featured-projects/silverstone-mimicking-natures-way-transform-co2-stone_en |access-date=2024-05-29 |website=cinea.ec.europa.eu |language=en}}

Carbfix has since early 2023 started the capture and injection of CO₂ and H₂S from the Nesjavellir Geothermal Power Plant in SW-Iceland as a part of the Europe Horizon 2020 funded GECO project.{{Cite web |title=Geothermal Emission Control {{!}} GECO Project {{!}} Fact Sheet {{!}} H2020 |url=https://cordis.europa.eu/project/id/818169 |access-date=2024-05-29 |website=CORDIS {{!}} European Commission |language=en}} The same approach is used as at the Hellisheiði Geothermal Power Plant, but with optimized capturing efficiency of the scrubbing tower. The gases are dissolved in condensate from the plant‘s turbines and injected into the basaltic subsurface below 900 m.{{Cite journal |last1=Galeczka |first1=Iwona Monika |last2=Stefánsson |first2=Andri |last3=Kleine |first3=Barbara I. |last4=Gunnarsson-Robin |first4=Jóhann |last5=Snæbjörnsdóttir |first5=Sandra Ósk |last6=Sigfússon |first6=Bergur |last7=Gunnarsdóttir |first7=Sveinborg Hlíf |last8=Weisenberger |first8=Tobias B. |last9=Oelkers |first9=Eric H. |date=March 2022 |title=A pre-injection assessment of CO2 and H2S mineralization reactions at the Nesjavellir (Iceland) geothermal storage site |url=https://doi.org/10.1016/j.ijggc.2022.103610 |journal=International Journal of Greenhouse Gas Control |volume=115 |pages=103610 |doi=10.1016/j.ijggc.2022.103610 |issn=1750-5836|url-access=subscription }}

The world’s first injection of CO₂ captured from the atmosphere was carried out in Hellisheiði in SW-Iceland in 2017, as part of the Europe H2020 funded project CarbFix2. The CO₂ was captured using a Direct Air Capture (DAC) unit developed by the Swiss green-tech company Climeworks. The CO₂ was then dissolved in water and injected into the basaltic subsurface.{{Cite web |title=Upscaling and optimizing subsurface, in situ carbon mineralization as an economically viable industrial option {{!}} CarbFix2 Project {{!}} Fact Sheet {{!}} H2020 |url=https://cordis.europa.eu/project/id/764760 |access-date=2024-05-29 |website=CORDIS {{!}} European Commission |language=en}}{{Cite journal |last1=Gutknecht |first1=Valentin |last2=Snæbjörnsdóttir |first2=Sandra Ósk |last3=Sigfússon |first3=Bergur |last4=Aradóttir |first4=Edda Sif |last5=Charles |first5=Louise |date=July 2018 |title=Creating a carbon dioxide removal solution by combining rapid mineralization of CO2 with direct air capture |journal=Energy Procedia |volume=146 |pages=129–134 |doi=10.1016/j.egypro.2018.07.017 |issn=1876-6102|doi-access=free }}

In 2021, the world’s first commercial DAC combined with storage plant, Orca, was commissioned in Hellisheiði in collaboration between Climeworks and Carbfix. The plant has the capacity to capture up to 3,600 tons of CO₂ directly from the atmosphere that are injected into basalts for permanent mineral storage.{{Cite web |title=Orca is Climeworks' new large-scale carbon dioxide removal plant |url=https://climeworks.com/plant-orca |access-date=2024-05-29 |website=Climeworks |language=en}}

In 2024 Climeworks and Carbfix are commissioning the Mammoth DAC plant, with the capacity to capture up to 36,000 tons per year which will be injected into the basalt for permanent mineral storage at the Geothermal Park in Hellisheiði.{{Cite web |title=Mammoth: our newest direct air capture and storage facility |url=https://climeworks.com/plant-mammoth |access-date=2024-05-29 |website=Climeworks |language=en}}{{Cite web |last=Calma |first=Justine |date=2022-06-29 |title=Construction begins on "Mammoth" direct air capture plant |url=https://www.theverge.com/2022/6/29/23188164/mammoth-direct-air-capture-plant-climeworks-groundbreaking-iceland |access-date=2024-05-29 |website=The Verge |language=en}}

Cross-border transport of CO₂ was first demonstrated as part of the DemoUpCarma project in August 2022.{{Cite web |last= |date=2024-05-29 |title=First CO2 transport arrived in Iceland |url=https://demoupcarma.ethz.ch/en/bssed-imagetexttags/Home-First-CO2-transport-arrived-in-Iceland/ |access-date= |website=}} The project was funded by the Swiss Federal Offices and led by ETH.{{Cite web |date=2024-05-29 |title=About DemoUpCARMA |url=https://demoupcarma.ethz.ch/en/project/about/}}{{Cite journal |last1=Becattini |first1=Viola |last2=Wiemer |first2=Stefan |last3=Mazzotti |first3=Marco |date=April 2024 |title=Accelerating the climate transition through scientist-led CO2 management pilot projects |url=https://www.nature.com/articles/s44286-024-00056-y |journal=Nature Chemical Engineering |language=en |volume=1 |issue=4 |pages=267–269 |doi=10.1038/s44286-024-00056-y |issn=2948-1198}} The CO₂ was captured from a biogas upgrading plant in Bern, Switzerland, and transported to Iceland where it was first injected at the Hellisheiði site. The current injection site of DemoUpCarma project is in Helguvík, Iceland, where the CO₂ is co-injected with seawater as part of the R&D project CO2Seastone.{{Cite web |title=CO2-Seastone |url=https://www.carbfix.com/co2-seastone |access-date=2024-05-29 |website=www.carbfix.com |language=en}}

In July 2021, Carbfix was awarded the largest research grant ever granted to an Icelandic company, when it was nominated for the EU Innovation Fund grant of 15 million € for the Coda Terminal project.{{Cite web |title=Coda Terminal |url=https://climate.ec.europa.eu/system/files/2022-12/if_pf_2022_coda_en.pdf |access-date=2024-05-29 |website=}}{{Cite web |title=Carbfix's Coda Terminal awarded large EU grant |url=https://www.carbfix.com/awarded-large-eu-grant |access-date=2024-05-29 |website=www.carbfix.com}}

The Coda Terminal will be developed in Straumsvík, SW-Iceland as the first cross-border carbon transport and storage hub in Iceland. CO₂ will be captured at industrial sites in N-Europe, focusing on the hard-to-abate sector, and shipped to the Terminal where it will be unloaded into onshore tanks for temporary storage. The CO₂ will then be pumped into a network of nearby injection wells where it will be dissolved in water during injection into the basaltic bedrock. The operations will be scaled up in steps reaching up to 3 million tons of CO₂ per year from 2031.{{Cite web |title=Coda Terminal |url=https://www.carbfix.com/codaterminal |access-date=2024-05-29 |website=www.carbfix.com |language=en}} For comparison, the {{CO2}}-emissions of Iceland, a country of some 400,000 people, varied between {{convert|3340000|t}} (2020) and {{convert|3810000|t}} (2008) in the 2007-2023 period.https://ourworldindata.org/co2/country/iceland Iceland's energy sector is among the lowest carbon emitting per unit of electricity produced due to the high penetration of hydropower and geothermal energy. However, per-capita electricity consumption is unusually high due to the large energy demand of Iceland's aluminum smelters.

{{Reflist}}

• [https://www.carbfix.com Carbfix.com – Website of the project]
• {{cite news|last=Brabant|first=Malcolm|title=To combat climate change, these scientists are turning CO2 into rock|date=August 23, 2016|work=PBS NewsHour|publisher=WETA-TV|url=https://www.pbs.org/newshour/show/combat-climate-change-scientists-turning-co2-rock|access-date=July 18, 2022}}
• {{YouTube|0iqBUSvnsAg|To combat climate change, these scientists are turning {{CO2}} into rock}}, Aug 23, 2016 PBS NewsHour

Category:Emissions reduction

Category:Environment of Iceland

Category:Geoengineering