Journal Article

The biological carbon pump in CMIP6 models

Baker, Chelsey A., Kennedy-Asser, Alan T., Wilson, Jamie D., Andrews, Oliver, Goldsworth, Fraser W., Adloff, Markus, Death, Ros M., Vosper, Emily, Blackledge, Benedict, de Melo Viríssimo, Francisco, Liu, Qian, Sieradzan, Katie R., Ying, Rui, Katavouta, Anna

2022

Overview

The biological carbon pump (BCP) stores ∼1,700 Pg C from the atmosphere in the ocean interior, but the magnitude and direction of future changes in carbon sequestration by the BCP are uncertain. We quantify global trends in export production, sinking organic carbon fluxes, and sequestered carbon in the latest Coupled Model Intercomparison Project Phase 6 (CMIP6) future projections, finding a consistent 19 to 48 Pg C increase in carbon sequestration over the 21st century for the SSP3-7.0 scenario, equivalent to 5 to 17% of the total increase of carbon in the ocean by 2100. This is in contrast to a global decrease in export production of –0.15 to –1.44 Pg C y−1. However, there is significant uncertainty in the modeled future fluxes of organic carbon to the deep ocean associated with a range of different processes resolved across models. We demonstrate that organic carbon fluxes at 1,000 mare a good predictor of long-term carbon sequestration and suggest this is an important metric of the BCP that should be prioritized in future model studies.

• Publisher: National Academy of Sciences
• Subject: 21st century / Atmosphere - chemistry / Atmospheric models / BRIEF REPORTS / Carbon / Carbon - analysis / Carbon Sequestration / Ecosystem / Environmental Sciences / Fluxes / Models, Theoretical / Ocean models / Oceans and Seas / Organic carbon / Physical Sciences / Trends / Uncertainty