NSFGEO-NERC: Collaborative Research: Exploring AMOC controls on the North Atlantic carbon sink using novel inverse and data-constrained models (EXPLANATIONS)

The ocean plays a vital role in mitigating climate change, currently absorbing roughly 25% of carbon dioxide emissions released into the atmosphere, with the potential to absorb more than 90% at long-term steady state. The North Atlantic Ocean absorbs a disproportionate amount of this carbon. The Atlantic Meridional Overturning Circulation (AMOC), along with its interactions with biogeochemical processes and ocean ecosystems, are key factors in determining the strength and variability of the North Atlantic carbon sink.

Although carbon cycle models are used to understand these processes and predict future carbon uptake, these models are often not data-constrained and can produce differing results. This makes it difficult to have confidence in future climate projections. This project aims to address this by 1) estimating the uptake, transport, and storage of carbon in the North Atlantic using newly-available data and numerical methods and 2) quantifying the role of AMOC in driving ocean carbon sink variability.

The research results will be shared broadly with the scientific community and the general public. The project will support a team of early career investigators, including postdoctoral researchers in the US and UK. Ultimately, this work will deliver key products with uncertainties to those responsible for disseminating climate science to policymakers, and improve numerical models for more accurate projections of climate change.

This is a project jointly funded by the National Science Foundation’s Directorate for Geosciences (NSF/GEO) and the National Environment Research Council (NERC) of the United Kingdom (UK) via the NSF/GEO-NERC Lead Agency Agreement. This Agreement allows a single joint US/UK proposal to be submitted and peer-reviewed by the Agency whose investigator has the largest proportion of the budget.

Upon successful joint determination of an award recommendation, each Agency funds the proportion of the budget that supports scientists at institutions in their respective countries.

The project team will produce estimates of carbon uptake, transport, and storage in the North Atlantic using novel approaches that combine available observational constraints (from RAPID and OSNAP moored time series and repeat ship transects) with cutting-edge models. The main goal is to explore the role of various factors in carbon sink variability and to separate contributions due to steady-state and non-steady-state processes.

They will focus on the period since 1990 and examine the consistency of different observations, the impact of the AMOC and ocean ecosystems, and the role of natural carbon fluxes in driving North Atlantic carbon sink variability. The team will adopt an integrated approach that uses inverse modeling, ocean state estimates, ocean biogeochemical models, and climate model output.

This approach will produce multiple complementary products for estimating carbon uptake, transport, and storage in the North Atlantic and help determine the AMOC's role in ocean carbon sink space-time variability.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.