Abstract

Carbon-capture and storage (CCS) is expensive but as commercialization is proving problematic and economic estimates of climate change costs escalate, non-mainstream alternatives should be discussed. We present a thought experiment based on potential for increased carbon capture on polar continental shelves. West Antarctic, and probably Arctic, continental shelves are sites of significant negative feedbacks on climate change through benthos carbon accumulation. At South Georgia, moraines on the margins of the continental shelf (bulldozed there by past glaciations) show much more biological richness and activity than the typical mud covering ~88% of the shelf. We estimate that most carbon accumulation, and ultimately sequestration, occurs at these moraines (12% of shelf). Seabed CCS by benthos could increase 400% if it was all rubble. We think this could be achieved with minimal environmental impacts but at current CCS values it would take 10,000 years (Antarctic) and 1000 years (Arctic) to recoup transport costs.

Keywords: Carbon immobilization; benthos; South georgia; CO₂; Antarctica