Removing Carbon Dioxide Through Artificial Upwelling and Downwelling: Legal Challenges and Opportunities

By Romany M. Webb, Korey Silverman-Roati, and Michael Gerrard

A 2022 report by the Intergovernmental Panel on Climate Change warned that, to keep global average temperatures within 1.5oC above pre-industrial levels, emissions must reach net-zero by mid-century. The report concluded that achieving net-zero emissions will require the removal of carbon dioxide from the atmosphere “to counterbalance hard-to-abate emissions” from sectors like agriculture, aviation, and shipping. The report further noted that, if deployed at large scales, carbon dioxide removal (“CDR”) could also be used to achieve net negative emissions and thus effectively reduce the atmospheric concentration of carbon dioxide.

A variety of CDR techniques, both terrestrial and ocean-based, have been proposed. This paper focuses on artificial upwelling and downwelling, an ocean-based approach which uses large, vertical pipes to cycle water between the surface and deep ocean. The goal is to upwell nutrient rich water from depth to the surface, where it will stimulate the growth of phytoplankton that uptake carbon dioxide from the atmosphere, and downwell carbon dioxide-saturated water from the surface to depth. This should, in theory, result in carbon dioxide being taken out of the atmosphere and sequestered in the deep ocean. However, further research is needed to fully assess the carbon sequestration potential of artificial upwelling and downwelling, as well as its possible co-benefits and risks.

Uncertainty regarding the laws governing artificial upwelling and downwelling has been identified as a potential barrier to research and deployment. This paper helps to fill existing knowledge gaps by analyzing the application of international and domestic (U.S.) law to artificial upwelling and downwelling.

Read the report, Removing Carbon Dioxide Through Artificial Upwelling and Downwelling: Legal Challenges and Opportunities, in Columbia Law School's Scholarship Archive