This section provides links to other independent work and references to interesting literature on GHG-removal.

Please note that our linking to these initiatives, organisations and publications does not imply any formal association between us, nor that they support the Earth Challenge. We nonetheless wanted to highlight and link to their efforts.

The Carbon Cycle:

  • The Global Carbon Project’s scientific goal is to develop a complete picture of the global carbon cycle [click here]

Cutting emissions in the first place:

As we keep saying, ways of taking greenhouse gases out of the air must go with deeps cuts greenhouse gas emissions in the first place. Right now:

  • Help get emissions reduction activities to a gigatonne scale with the Carbon War Room, who’ve recently teamed up with the Rocky Mountain Institute  [click here]
  • Learn about the science of climate change, the international action being taken and the economic rationale behind a price on carbon through the Climate Commission [click here]
  • Read the IPCC AR5 reports, especially the synthesis report. [click here]
  • …and use this ‘Trillonth Tonne’ clock by the University of Oxford as a reminder that yes, the clock is ticking  [click here]

…and while you’re at it:

  • Join the B Team in catalysing a better way of doing business, for the well-being of people and the planet. [click here]
  • Check out the work of Ocean Unite. Making waves with definitive science and clear policy options point the way to what must be done to restore and protect marine life; [click here]
  • Become part of The Elders’ Global Village [click here]
  • And end the War on Drugs [click here]

Air Miners:

  • Air Miners is the index of companies and projects mining carbon from the air. They also recently did an early run of planters made with CO2 extracted from the atmosphere [click here]

Biodiversity for a Livable Climate:

  • Biodiversity for a Livable Climate’s goal is to contribute to planetary regeneration through research, education, collaboration and action to restore essential global biodiversity.  [click here]

Carbon 180:

  • Carbon180 is a new breed of climate-focused NGO on a mission to fundamentally rethink carbon. We partner with policymakers, scientists and businesses around the globe to develop policy, promote research, and advance solutions that transform carbon from a liability to an asset (a pollutant to a resource) and foster a prosperous, carbon-conscious economy that removes more from the atmosphere than we emit [click here].

Carbon A List:

  • Carbon A List is on a mission accelerate the flow of money and awareness to novel innovations that can close the carbon cycle [click here]

The Nature Conservancy: Natural Climate Solutions

  • Nature’s Make or Break Potential for Climate Change: New study shows we’ve been underestimating nature’s role in tackling climate change [click here]

Project Drawdown:

  • Project Drawdown is a nonprofit organization. Made up of a coalition of scholars, scientists, entrepreneurs, and advocates from across the globe, Drawdown has produced the most comprehensive plan ever proposed to reverse global warming. [click here]


  • Learn about world-leading examples of restoration & regeneration, beyond and including the carbon cycle, at Revitalization News [click here]


Greenhouse gas removal overviews/synthesis reports:

  • Caldecott, B., Lomax, G., Workman, M. (2015) Stranded Carbon Assets and Negative Emissions Technologies Working Paper, Stranded Assets Programme, Smith School of Enterprise and the Environment, University of Oxford [click here]
  • Dorr, A. (2016) The impact pulse and restoration curves: Going beyond mitigation and stabilization, Anthropocene, Volume 16, December 2016, Pages 61–66 [click here]
  • Edenhofer, O., R. Pichs-Madruga, Y. Sokona, E. Farahani, S. Kadner, K. Seyboth, A. Adler, I. Baum, S. Brunner, P. Eickemeier, B. Kriemann, J. Savolainen, S. Schlömer, C. von Stechow, T. Zwickel and J.C. Minx (eds.) (2014)  Climate Change 2014, Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. [click here] – see chapter 6
  • Fuss, S., Canadell, J.G., Peters, G.P., Tavoni, M., Andrew, R.M., Ciais, P., Jackson, R.B., Jones, C.D., Kraxner, F., Nakicenovic, N., Le Quéré, C., Raupach, M.R., Sharifi, A., Smith, P. and Yamagata, Y. (2015) Betting on negative emissions,  Nature Climate Change, Volume:4, Pages:850–853, DOI:doi:10.1038/nclimate2392 [click here]
  • Gasser, T., Guivarch, C., Tachiiri, K., Jones, C. D., and Ciais, P. (2015) Negative emissions physically needed to keep global warming below 2°C, Nature Communications, Volume: 6, Article number: 7958 DOI:doi:10.1038/ncomms8958 [click here]
  • Hansen, J., Sato, M., Kharecha, P., von Schuckmann, K., Beerling, D. J., Cao, J., Marcott, S., Masson-Delmotte, V., Prather, M. J., Rohling, E. J., Shakun, J., Smith, P., Lacis, A., Russell, G., and Ruedy, R. (2017) Young people’s burden: requirement of negative CO2 emissions, Earth Syst. Dynam., 8, 577-616,,[click here]
  • Honneger, M & Reiner, D. (2018) The political economy of negative emissions technologies: consequences for international policy design, Climate Policy, [click here]
  • Kriegler, E., Edenhofer, O., Reuster, L., Luderer, G. and Klein, D. (2013) Is atmospheric carbon dioxide removal a game changer for climate change mitigation? Climatic Change, 118: 45-57 [click here]
  • Larkin, A., Kuriakose, L., Sharmina, M., & Anderson, K. (2017) What if negative emission technologies fail at scale? Implications of the Paris Agreement for big emitting nations. Climate Policy. doi: 10.1080/14693062.2017.1346498 [click here]
  • Lomax, G., Lenton, T.M., Adeosun, A. and Workman, M. (2015) Investing in negative emissions, Nature Climate Change, Volume:5, Pages:498–500, DOI:doi:10.1038/nclimate2627 [click here] 
  • McLaren, D. (2012) Negatonnes – an Initial Assessment of the Potential for Negative Emissions Techniques to Contribute Safely and Fairly to Meeting Carbon Budgets in the 21st Century – a report by Duncan McLaren for Friends of the Earth [click here]
  • Meadowcroft, J. (2013) Exploring negative territory Carbon dioxide removal and climate policy initiatives, Climatic Change, 118: 137-149 [click here]
  • Milne, J.L. and Field, C.B. (2013) Assessment Report from the GCEP Workshop on Energy Supply with Negative Carbon Emissions, Stanford University [click here]
  • National Research Council. Climate Intervention: Carbon Dioxide Removal and Reliable Sequestration. Washington, DC: The National Academies Press, 2015 [click here]
  • Obersteiner, M., Bednar, J.B., Wagner, F., Gasser G., Ciais P., Forsell N., Frank, S., Havlik, P., Valin, H., Janssens, I.A., Peñuelas. J.,  and Schmidt-Traub. G. (2018) How to spend a dwindling greenhouse gas budget, Nature Climate Change 8, 7–10, doi:10.1038/s41558-017-0045-1 [click here]
  • Peters, G & Geden, O (2017) Catalysing a political shift from low to negative carbon, Nature Climate Change, 7, 619–621(2017) doi:10.1038/nclimate3369 [click here]
  • Pinder, C. (2014) Below Zero: Carbon Removal and the Climate Challenge, The Climate Institute, March 2014 [click here]
  • Rockström, J., Gaffney, O., Rogelj, J., Meinshausen, M., Nakicenovic, N., Schellnhuber, H. J. (2017) A roadmap for rapid decarbonisation, Science, Vol. 355, Issue 6331, pp. 1269-1271, DOI: 10.1126/science.aah3443 [click here]
  • Royal Society (2018) Greenhouse Gas Removal [click here]
  • Smith, P., Davis, S.J., Creutzig, F., Fuss, S., Minx, J., Gabrielle, B., Kato, E., Jackson, R.B., Cowie, A., Kriegler, E., van Vuuren, D.P., Rogelj, J., Ciais, P., Milne, J., Canadell, McCollum, D., Peters, G., Andrew, R., Krey, V., Shrestha, G., Friedlingstein, P., Gasser, T., Grübler, A., Heidug, W.K., Jonas, M., Jones, C.D., Kraxner, F., Littleton, E., Lowe, J., Moreira, J.R., Nakicenovic, N., Obersteiner, M., Patwardhan, A., Rogner, M., Rubin, ED., Sharifi, A., Torvanger, A.,  Yamagata, Y., Edmonds, J. and Yongsung, C. (2015) Biophysical and economic limits to negative CO2 emissions, Nature Climate Change, DOI:doi:10.1038/nclimate2870 [click here]
  • Tavoni, M and Socolow, R. (2013) Modeling meets science and technology: an introduction to a special issue on negative emissions, Climatic Change, 118: 1-14 [click here]
  • van Vuuren, D.P., Deetman, S., van Vliet, J., van den Berg, M., van Ruijve, B.J. and Koebl, B. (2013) the role of negative CO2 emissions for reaching 2 °C—insights from integrated assessment modelling, Climatic Change, 118: 15-27 [click here]
  • UNEP (2017) The Emissions Gap Report 2017. A UN Environment Synthesis Report, United Nations Environment Programme (UNEP), Nairobi [click here]
  • Williamson, P. (2016) Emissions reduction: Scrutinize CO2 removal methods, Nature, Vol. 530, Issue 7589, pages: 153–155 doi:10.1038/530153a [click here]
  • Xu, Y. and Ramanathan, V. (2017) Well below 2 °C: Mitigation strategies for avoiding dangerous to catastrophic climate changes, PNAS, September 26, 2017, vol. 114, no. 39, 10315-10323, doi:10.1073/pnas.1618481114 [click here]


Cornell University and University of Edinburgh have world-leading biochar research programmes, with links to their publications. Check out the British Biochar Foundation, the International Biochar Initiative, and the US Biochar Initiative too.

  • The British Biochar Foundation [click here]
  • Biochar Soil Management – Cornell University [click here]
  • The European Biochar Research Network [click here]
  • The International Biochar Initiative [click here]
  • UK Biochar Research Centre – Edinburgh University [click here]
  • The Unites States Biochar Initiative [click here]
  • FertiPlus: co-funded by the European Commission, reducing mineral fertilisers and agro-chemicals by recycling treated organic waste compost and biochar [click here]
  • Biochar 101: a report by Dovetail Partners for the US Department of Agriculture [click here]
  • Woolf, D., Amonette, J.E., Street-Perrott, F.A., Lehmann, J. and Joseph, S. (2010) Sustainable biochar to mitigate global climate change, Nature Communications, doi: 10.1038/ncomms1053 [click here]

Bio-Energy with Carbon Capture and Storage (“BECCS”):

  • Biomass with CO2 capture and storage (Bio-CCS) – European Technology Platform for Zero Emissions Power Plants [click here]
  • Edmonds, J., Luckow, P., Calvin, K., Wise, M., Dooley, J., Kyle, P., Kim, S.H., Patel, P. and Clarke, L. (2013) Can radiative forcing be limited to 2.6 Wm−2 without negative emissions from bioenergy AND CO2 capture and storage? Climatic Change, 118: 29-43 [click here]
  • Gough, C. and Upham, P. (2011) Biomass energy with carbon capture and storage (BECCS or Bio-CCS), Greenhouse Gases: Science and Technology, Volume 1, Issue 4. DOI: 10.1002/ghg.34 [click here]
  • Powell, T.W.R. and Lenton, T. M. (2012), Future carbon dioxide removal via biomass energy constrained by agricultural efficiency and dietary trends, Energy and Environmental Science, DOI: 10.1039/c2ee21592f [click here]
  • Sanchez, D.L., Nelson, J.H., Johnston, J., Mileva, A. & Kammen, D. (2015), Biomass enables the transition to a carbon-negative power system across western North America, Nature Climate Change, 5, 230–234, doi:10.1038/nclimate2488 [click here]

Direct Air Capture (“DAC”):

The Center for Negative Carbon Emissions (CNCE) at Arizona State University is advancing carbon management technologies that can capture carbon dioxide directly from ambient air in an outdoor operating environment. Their aim is to demonstrate systems that over time increase in scope, complexity, reliability and efficiency while lowering the cost of carbon dioxide capture from air.

  • Arizona State University – Center for Negative Carbon Emissions [click here]
  • Center for Carbon Removal (2015) Carbon sequestration through direct air capture [click here]
  • Chen, C. and Tavoni, M. (2013) Direct air capture of CO2 and climate stabilization: A model based assessment, Climatic Change, 118: 59-72 [click here]
  • Fox, T. (2011) Air Capture: Negative Emissions and Carbon Recycling – Institution of Mechanical Engineers [click here]
  • Keith, D.W., Holmes, G., St. Angelo, D., Heidel, K. (2018) A Process for Capturing COfrom the Atmosphere, Joule, vol 2, 1–22, August 15 2018, [click here]
  • Keith, D.W. and Holmes, G., (2012) An air-liquid contactor for large-scale capture of CO2 from air, Phil. Trans. R. Soc. A (2012) 370, 4380–4403 doi:10.1098/rsta.2012.0137 [click here]
  • Marcucci, A., Kypreos, S. and Panos, E. (2017) The road to achieving the long-term Paris targets: energy transition and the role of direct air capture, Climatic Change, 144: 181. [click here]
  • Mazzotti, M., Baciocchi, R., Desmond, M.J. and Socolow, R.H. (2013) Diret air capture of CO2 with chemicals: optimization of a two-loop hydroxide carbonate system using a countercurrent air-liquid contactor, Climatic Change, 118: 119-135 [click here]
  • Socolow, R. et al. (2011) Direct Air Capture of CO2 with Chemicals: A Technology Assessment for the APS Panel on Public Affairs [click here]
  • Keith, D. W. and Holmes, G., (2011) Comments on the APS report on Direct Air Capture [click here]
  • Wurzbacher, J.A., Gebald, C., Piatkowski, N., and Steinfeld, A. (2012) Concurrent Separation of CO2 and H2O from Air by a Temperature-Vacuum Swing Adsorption/Desorption Cycle, Environ. Sci. Technol. 2012, 46, 9191−9198, [click here]

 Enhanced Weathering:

  • Hartmann, J. West, J., Renforth, P., Köhler, P., De La Rocha, C., Wolf-Gladrow, D.A., Dürr, H., Scheffran, J. (2013): Enhanced Chemical Weathering as a Geoengineering Strategy to Reduce Atmospheric Carbon Dioxide, a Nutrient Source and to Mitigate Ocean Acidification, Reviews of Geophysics, DOI: 10.1002/rog.20004: [click here]
  • Kelemen, P.B., Matter, J., Streit, E.E., Rudge, J.F., Curry, W.B., Blusztajn, J. (2011) Rates and Mechanisms of Mineral Carbonation in Peridotite: Natural Processes and Recipes for Enhanced, in situ CO2 Capture and Storage, Annual Review of Earth and Planetary Sciences, Volume: 39 p.93, [click here]
  • Köhler, P., Abrams, J. F., Völker, C., Hauck, J., & Wolf-Galdrow, D. A. (2013) Geoengineering impact of open ocean dissolution of olivine on atmospheric CO2, surface ocean pH and marine biology. Environmental Research Letters, 8, 014009. [click here]
  • Köhler, P., Hartmann, J., & Wolf-Galdrow, D. A. (2010) Geoengineering potential of artificially enhanced silicate weathering of olivine. Proceeding of the National Academy of Science, 107 20228-20233 [click here]
  • Manning D.A.C., Renforth, P. (in press) Passive sequestration of atmospheric CO2 through coupled plant-mineral reactions. Environmental Science and Technology[click here]
  • Renforth, P. (2012) The potential of enhanced weathering in the UK. International Journal of Greenhouse Gas Control. 10 1-15. [click here]
  • SalekS.S., Kleerebezem R., Jonkers H.M., Witkamp G.J., van LoosdrechtM.C.M. (2013) Mineral CO2 sequestration by environmental biotechnological processes, Trends in Biotechnology, Volume 31, Issue 3, 139-146. [click here]
  • SalekS.S., Kleerebezem R., Jonkers H.M., Voncken J.H.L., van LoosdrechtM.C.M. (2012) Determining the impacts of fermentative bacteria on silicate minerals dissolution kinetics, Applied Microbiology and Biotechnology. DOI: 10.1007/s00253-012-4590-2 [click here]
  • Schuiling, R.D. (2013) Farming nickel from non-ore deposits, combined with CO2  squestration, Natural Science, Volume 5, Number 4, April 2013 DOI: 10.4236/ns.2013.54057 [click here]
  • Schuiling, R.D. (2012) Capturing CO2 from air. Proc Natl Acad Sci USA, 10.1073/pnas. 1200990109. [click here]
  • Schuiling, R.D. and de Boer, P.L. (2011) Rolling stones; fast weathering of olivine in shallow seas for cost-effective CO2 capture and mitigation of global warming and ocean acidification, Earth Syst. Dynam. Discuss., 2, 551-568, doi:10.5194/esdd-2-551-2011 [click here]
  • Schuiling, R.D. and Krijgsman, P. (2006) Enhanced weathering; an effective and cheap tool to sequester CO2 . Climatic Change, 74, nrs 1-3, p.349-354. [click here]
  • Taylor, L.L., Quirk, J., Thorley, R.M.S., Kharecha, P.A., Hansen, J., Ridgwell, A., Lomas, M.R., Banwart, S.A., and Beerling, D.J., (2016): Enhanced weathering strategies for stabilizing climate and averting ocean acidification. Nature Clim. Change, 6, no. 4, 402-406, doi:10.1038/nclimate2882. [click here]
  • Washbourne, C-L., Renforth, P. Manning, D.A.C. (2012) Investigating carbonate formation in urban soils as a method for atmospheric carbon capture  and storage. Science of the total environment. 431, 166-175. [click here]

Land Management / Ecosystem Sequestration / Soil Carbon:

  • Center for Carbon Removal (2015) Carbon sequestration in the agriculture sector [click here]
  • Griscom, B. W., Adams, J., Ellis, P.W., Houghton, R. A., Lomax, G., Mitevad, D. A., Schlesinger, W. H., Shoch, D.,  Siikamäki, J.V., Smith, P., Woodbury, P., Zganjar, C., Blackman, A., Campari, J., Conant, R.T., Delgado, C., Elias, P., Gopalakrishna, T., Hamsik, M.R., Herrero, M., Kiesecker, J., Landis, E., Laestadius, L., Leavitt, S. M., Minnemeyer, S., Polasky, S., Potapov, P., Putz, F.E., Sanderman, J., Silvius, M., Wollenbergs, E., and Fargione, J. (2017) Natural Climate Solutions, PNAS, vol. 114, no. 44, 11645–11650doi: 10.1073/pnas.1710465114 [click here]
  • Reynaldo, V., Banwart, S., Black, H., Ingram, J., Joosten, H., Milne, E., Noellemeyer, E., and Baskin, Y. (2012) The Benefits of Soil Carbon, managing soils for multiple economic, societal and environmental benefits, UNEP Year Book 2012 [click here]
  • Sanderman, J,. Hengl, T., Fiske, G.J. (2017) Soil carbon debt of 12,000 years of human land use, PNAS 2017, 114 (36) 9575-9580; doi:10.1073/pnas.1706103114 [click here]
  • Schmitz, O.J., et al. (2014) Animating the carbon cycle. Ecosystems 17:344-359 [click here]
  • Schmitz, O. J. (2008) Effects of Predator Hunting Mode on Grassland Ecosystem Function. Science 319, 952 [click here]
  • Smith, L.J. and Torn, M.S. (2013) Ecological limits to terrestrial biological carbon dioxide removal, Climatic Change, 118: 89-103 [click here]
  • Stockmann, U., Adams, M.A., Crawford, J.W., Field, D.J., Henakaarchchi, N., Jenkins, M., Minasny, B., McBratney, A.B., de Remy de Courcelles, V., Singh, K., Wheeler, I., Abbott, L., Angers, D.A., Baldock, J., Bird, M., Brookes, P.C., Chenu, C., Jastrow, J.D., Lal, R., Lehmann, J., O’Donnell, A.G., Parton, W.J., Whitehead, D., Zimmermann, M. (2013) The knowns, known unknowns and unknowns of sequestration of soil organic carbon, Agriculture, Ecosystems & Environment, Volume 164, 1 January 2013, Pages 80-99, ISSN 0167-8809, [click here]
  • Strickland, M. S., Hawlena, D., Reese, A., Bradford, M. A., Schmitz, O. J. (2013) Trophic cascade alters ecosystem carbon exchange. [click here]
  • Teague, W.R., Dowhower, S.L., Baker, S.A., Haile, N., DeLaune, P.B. and Conover, D.M. (2011) Grazing management impacts on vegetation, soil biota and soil chemical, physical and hydrological properties in tall grass prairie, Agriculture, Ecosystems & Environment, Vol. 141, Issues 3-4, May 2011, pages 310-322,  [click here]

Other GHG-removal proposals:

  • Vichi, M., Navarra, A., Fogli, P.G. (2013) Adjustment of the natural ocean carbon cycle to negative emission rates, Climatic Change, 118: 105-118 [click here]

Research initiatives that have included GHG-removal*

  • Bellamy, R., Chilvers, J., Vaughan, N.E. and Lenton, T.M. (2012): A review of climate geoengineering appraisals. WIREs Climate Change, 3, 597 – 615. [click here]
  • European Transdisciplinary Assessment of Climate Geoengineering (EuTRACE) project [click here]
  • Forum for Climate Engineering Assessment (FCEA0 [click here]
  • Heyward, C. (2013): Situating and Abandoning Geoengineering: A Typology of Five Responses to Dangerous Climate Change. In: APSC 46 (01), pp. 23–27. DOI 10.1017/S1049096512001436 [click here]
  • Integrated Assessment of Geoengineering Proposals [click here]
  • Lenton, T.M., & Vaughan, N.E. (2009) The radiative forcing potential of different climate geoengineering options, Atmos. Chem. Phys., 9, 5539-5561, 2009, doi:10.5194/acp-9-5539-2009 [click here]
  • Natural Environment Research Council (2016) Announcement of Opportunity: Greenhouse Gas Removal from the Atmosphere [click here]
  • The Oxford Geoengineering Programme [click here]
  • The Royal Society – Geoengineering the climate: science, governance and uncertainty [click here]
  • The UK Government’s House of Commons Science and Technology Committee’s report on the regulation of Geo-engineering [click here]


*please note that the Virgin Earth Challenge is only interested in ways of sustainably removing greenhouse gases from the atmosphere, other proposals discussed under the umbrella term of Geoengineering, like directly interfering with solar radiation budgets, are well beyond our scope. See our FAQs for more information.