Marine carbon sink dominated by biological pump after temperature overshoot

[Tom Goreau]

• 
  Published: 30 September 2024

Marine carbon sink dominated by biological pump after temperature overshoot

• Wolfgang Koeve, 
• Angela Landolfi, 
• Andreas Oschlies & 
• Ivy Frenger 

Nature Geoscience volume 17, pages1093–1099 (2024)

Abstract

In the event of insufficient mitigation efforts, net-negative CO₂ emissions may be required to return climate warming to acceptable limits as defined by the Paris Agreement. The ocean acts as an important carbon sink under increasing atmospheric CO₂ levels when the physico-chemical uptake of carbon dominates. However, the processes that govern the marine carbon sink under net-negative CO₂ emission regimes are unclear. Here we assessed changes in marine CO₂ uptake and storage mechanisms under a range of idealized temperature-overshoot scenarios using an Earth system model of intermediate complexity over centennial timescales. We show that while the fate of CO₂ from physico-chemical uptake is very sensitive to future atmospheric boundary conditions and CO₂ is partly lost from the ocean at times of net-negative CO₂ emissions, storage associated with the biological carbon pump continues to increase and may even dominate marine excess CO₂ storage on multi-centennial timescales. Our findings imply that excess carbon that is attributable to the biological carbon pump needs to be considered carefully when quantifying and projecting changes in the marine carbon sink.

 

[Greg Rau]

Obviously? The primary driver of natural mCDR presently is the CO2 overpressure in the atmosphere. Remove that and you’ve only got biology (marine photosynthesis) and geochemistry (RW) to provide natural mCDR(?)

Greg

Sent from my iPhone

On Nov 8, 2024, at 2:38 AM, Tom Goreau <gor...@globalcoral.org> wrote:



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