Marine carbon sink after temperature overshoot is dominated by biological pump carbon

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Feb 12, 2024, 7:25:21 PM2/12/24

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[...] Net removal of CO2 from the atmosphere may be required to reach the Paris Agreement

goals to limit warming well below 2°C. Under such ‘net-negative-emissions’, the relative role

of different marine processes in storing additional CO2 remains unknown. Here we use

idealized Earth System model experiments to understand the response of different marine

carbon uptake and storage mechanisms under a range of idealized emission scenarios. We

find that the physical-chemical mechanisms, generally known to dominate under increasing

CO2-emission, contribute little to additional CO2 storage after CO2 or temperature overshoot.

Biological-carbon storage emerges as an increasingly and eventually dominating carbon-

storing mechanisms on multi-centennial timescales. Understanding how the ocean responds

to complex emission trajectories is essential to guide science-based solutions to the climate crises.[...]

MH] Oceanic Farming is likely more of a CDR need than just another mCDR option.

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Feb 13, 2024, 1:30:23 PM2/13/24

to Carbon Dioxide Removal

[...] With potentially delayed CO2-mitigation efforts, net-negative CO2-emissions may be required

to return to acceptable limits of climate warming as defined by the Paris Agreement. The

ocean is an important CO2 sink under increasing atmospheric pCO2, when physico-chemical

CO2-uptake dominates. The processes that govern its role under net-negative CO2-emission

regimes are, however, unclear. Here we assess changes in marine CO2-uptake and storage

mechanisms under a range of idealized temperature-overshoot scenarios in an Earth System

model of intermediate complexity over centennial timescales. We show that while the fate

of CO2 from physical-chemical uptake is very sensitive to future atmospheric boundary

conditions, storage associated with the biological carbon pump continues to increase and

may even dominate marine excess CO2 storage on multi-centennial time scales. Since change

in biological pump carbon is strongly linked to the oxygenation status of the ocean,

improved prediction of marine deoxygenation turns out to be a key to better forecast the

future of the marine carbon sink on multi-centennial time scales.[...]

MH] Improvements in Oceanic Farming technologies should be able to take advantage of this longterm trend.

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Feb 14, 2024, 4:03:04 PM2/14/24

to Carbon Dioxide Removal

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