Environmental science aspects

Most natural history marine CDR research to date has been conducted on a theoretical basis or with computer models (e.g., Rickels et al., 2019; Keller et al., 2018ab). For some methods, laboratory and small-scale field experiments have also been conducted to gain an understanding of fundamental processes (e.g., Brewer et al., 2002; de Lannoy et al., 2018). However, large-scale field experiments have never been conducted. Previous research has shown that some methods have more potential than others and that almost all methods appear to have specific side effects that can be positive or negative (Keller et al., 2018; GESAMP, 2019).

As recent assessments have shown (see GESAMP 2019), there are still many gaps in knowledge and only some of the most fundamental questions have been answered. However, it is already clear that the scale at which CDR would need to be implemented (Mt to Gt amounts of annual CDR) would require the manipulation of extensive ocean regions over long time periods. Currently, there is a lack of a systematic comprehensive approach to bridge these different scales through a problem-oriented integration of laboratory, field, and modeling studies, including an analysis of currently available or emerging technologies for medium- to large-scale ocean observations (GESAMP 2019; Gattuso et al., 2018).


Brewer, P. G., Peltzer, E.T., Friederich, G., & Rehder, G. (2002), Experimental determination of the fate of rising CO2 droplets in sea water. Environm. Sci. Techn., 36, 5441-5446. https://doi.org/10.1021/es025909r

de Lannoy, C.-F., Eisaman, M. D., Jose, A., Karnitz, S. D., DeVaul, R. W., Hannun, K., & Rivest, J. L. B. (2018), Indirect ocean capture of atmospheric CO2: Part I. Prototype of a negative emissions technology. International Journal of Greenhouse Gas Control, 70, 243–253. https://doi.org/10.1016/j.ijggc.2017.10.007

GESAMP (2019), High level review of a wide range of proposed marine geoengineering techniques. (Boyd, P.W. and Vivian, C.M.G., eds.). (IMO/FAO/UNESCO-IOC/UNIDO/WMO/IAEA/UN/UN Environment/UNDP/ISA Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection). Rep. Stud. GESAMP No. 98, 144 p.

Gattuso, J.-P., Magnan, A. K., Bopp, L., Cheung, W. W. L., Duarte, C. M., Hinkel, J., et al. (2018), Ocean solutions to address climate change and its effects on marine ecosystems. Frontiers in Marine Science, 5, 337. https://doi.org/10.3389/FMARS.2018.00337

Keller, D.P., (2018), Marine Climate Engineering. In M. Salomon & T. Markus (Eds.), Handbook on Marine Environment Protection. Springer. https://doi.org/10.1007/978-3-319-60156-4_13

Keller, D. P., Lenton, A., Littleton, E. W., Oschlies, A., Scott, V., & Vaughan, N. E. (2018a), The Effects of Carbon Dioxide Removal on the Carbon Cycle. Current Climate Change Reports, 4(3), 250–265. https://doi.org/10.1007/s40641-018-0104-3

Keller, D. P., Lenton, A., Scott, V., Vaughan, N. E., Bauer, N., Ji, D., et al. (2018b), The Carbon Dioxide Removal Model Intercomparison Project (CDRMIP): rationale and experimental protocol for CMIP6. Geoscientific Model Development, 11(3), 1133–1160. https://doi.org/10.5194/gmd-11-1133-2018

Rickels, W., Merk, C., Reith, F., Keller, D., & Oschlies, A. (2019), (Mis)conceptions about modelling of negative emissions technologies. Environmental Research Letters, 14: 104004. https://doi.org/10.1088/1748-9326/ab3ab4