Pathway 101: Ocean CDR
What “Ocean CDR” actually means Ocean carbon dioxide removal is a family of techniques that use the sea — the planet’s largest active carbon reservoir, holding roughly 50 times more carbon than the atmosphere — to draw down atmospheric CO₂ and keep it down. The ocean already absorbs about a quarter of annual anthropogenic emissions through air-sea gas exchange (Friedlingstein et al., 2023). Ocean CDR approaches either accelerate that natural uptake (by shifting seawater chemistry) or use biology to fix carbon and export it below the mixed layer, where it stays out of atmospheric contact for centuries to millennia. The appeal for buyers chasing durable removal is straightforward: the storage reservoir is enormous, and the residence times — particularly for bicarbonate ion in the deep ocean — are on the order of 10,000 years (Siegel et al., 2021). ...
