Influence of deep-sea sediments on the durability of carbon storage through Ocean Alkalinity enhancement
durch
8A-002 - Hörsaal Ostufer / Lecture Hall East
GEOMAR - Standort Ostufer / GEOMAR - East Shore
Abstract:
Ocean Alkalinity Enhancement (OAE) enhances CO₂ uptake of the ocean, but its long-term storage durability depends on the persistence of the added alkalinity. Natural processes such as sedimentary CaCO₃ dynamics and terrestrial weathering can alter alkalinity on millennial timescales, affecting OAE durability. Using the UVic 2.10 OPEM Earth System Model, I ran 10,000-year simulations with varying sediment and weathering formulations under three emission pathways (SSP1-2.6, SSP2-4.5, SSP3-7.0) and one OAE scenario (5 Pg Ca(OH)₂ yr⁻¹ for 50 years). Results show that OAE durability is influenced by deep-sea sediments only on millennial timescales but the sedimentary processes create an increasing uncertainty in CO2 storage capacity of up to 50%, depending on the emission scenario. These findings emphasize the need to account for Earth system feedbacks when assessing OAE potential and carbon credit allocation.
FB2 Office