Unraveling AMOC-CO2 feedbacks during the warmer-than-present Last Interglacial

Información del proyecto

MIS-5e

Identificador del acuerdo de subvención: 101109166

DOI

10.3030/101109166

Fecha de la firma de la CE 10 Mayo 2023

Fecha de inicio 1 Septiembre 2023

Fecha de finalización 31 Agosto 2026

Financiado con arreglo a

• Marie Skłodowska-Curie Actions (MSCA)

Coste total

Sin datos

Aportación de la UE

€ 289 407,84

Coordinado por

HELMHOLTZ-ZENTRUM FUR OZEANFORSCHUNG KIEL (GEOMAR)
Germany

Periodic Reporting for period 1 - MIS-5e (Unraveling AMOC-CO2 feedbacks during the warmer-than-present Last Interglacial)

Período documentado: 2023-09-01 hasta 2025-08-31

Resumen del contexto y de los objetivos generales del proyecto

The MIS-5e project investigates climate instability in the North Atlantic during the last interglacial period (129,000 to 115,000 years ago), which is widely regarded as one of the most relevant analogues for the projected global climate at the end of this century. The project seeks to understand the feedback mechanisms between ocean circulation variability, particularly the Atlantic Meridional Overturning Circulation (AMOC), and carbon cycling during this time.

The project focuses on paleoceanographic and paleoclimate reconstructions based on high-resolution geochemical data. In collaboration with scientists from GEOMAR and WHOI, I am analyzing multiple sediment cores and fossil corals from the North Atlantic using a suite of geochemical proxies to reconstruct past ocean and climate conditions. Isotopic data (δ¹³C, εNd, δ¹¹B) are used to assess changes in water mass chemistry and circulation patterns, while elemental ratios (Cd/Ca, B/Ca) provide insights into past nutrient levels and carbonate ion concentrations. The overarching goal is to fully leverage the last interglacial period as a natural experiment for understanding ocean-climate feedbacks under warmer-than-present conditions, offering valuable context for future climate projections.

Trabajo realizado desde el comienzo del proyecto hasta el final del período abarcado por el informe y los principales resultados hasta la fecha

As part of research on the AMOC during the last interglacial period, I conducted extensive geochemical and isotopic analyses at WHOI. This included trace element analyses, neodymium (Nd) isotope analysis and stable isotope analyses (δ¹³C and δ¹⁸O) on marine sediment cores. Sample preparation involved washing, sieving, and microscopic picking of foraminifera, followed by clay removal, dissolution, column chemistry, reductive and oxidative cleaning protocols, and ICP-MS measurements.

Key achievements:
- Developed end-member constraints for AMOC source waters during the last interglacial period.
- Reconstructed AMOC variability at a high resolution, providing a dataset suitable for validation and improvement of paleo-climate models.
- Prepared a comprehensive dataset to the PANGAEA data repository.
- First-author publication currently in preparation.

Avances que van más allá del estado de la técnica e impacto potencial esperado (incluida la repercusión socioeconómica y las implicaciones sociales más amplias del proyecto hasta la fecha)

The project results will directly address a critical knowledge gap in the ocean–climate nexus by significantly advancing our understanding of the ocean’s role in regulating atmospheric CO2 levels. However, continued work at GEOMAR (Work Packages 3 and 4), as outlined in the Description of Action (DoA), remains essential to fully achieve these objectives