Carbon Dioxide Removal: What’s Worth Doing? A Biophysical and Public Need Perspective

The world is experiencing unprecedented environmental and economic challenges posed by climate change. The need to reduce carbon emissions by identifying and executing effective technologies for mitigating carbon emissions is critical. One such technology is carbon dioxide removal.

In a new journal article published in PLOS Climate, June Sekera and coauthors examine two contrasting approaches to carbon dioxide removal (CDR)—mechanical and biological. The study analyzed the effectiveness, resource efficiency and environmental co-impacts of these two approaches.

Findings reveal that biological methods significantly outperform mechanical methods in terms of overall effectiveness. Mechanical methods, such as Carbon Capture and Storage and Direct Air Capture, barely capture CO₂ from the atmosphere and in some cases have even added to the overall emissions. Biological methods, in contrast, are capable of removing substantial amounts of CO₂ from the atmosphere. The study estimates that over 2 gigatons of CO₂ in the US could be reduced in 10-20 years with biological methods. 

Biological methods are also more resource efficient than mechanical methods of carbon removal. Sekera’s analysis estimates that mechanical methods can be 25 to 50 times more expensive than biological methods. Additionally, biological methods exhibit largely positive impacts on the environment, including flood control, drought mitigation and improved air and water quality. In contrast, mechanical methods are associated with several adverse co-impacts due to the risks of pipeline ruptures and CO₂ leakage.

Despite these advantages, current government policies provide substantial subsidies, tax credits and other incentives to mechanical CDR methods. Sekera advocates for fundamental policy reform, urging a reduction in public funding for mechanical methods and a substantial redirection of these resources toward proven and more effective biological methods. The authors also stress the need for investments in monitoring technologies to ensure the credibility and accountability of CDR outcomes.