GeodYnamic PerTubations of clImate Signals

The year 2025 marked a decisive transition for the GYPTIS project from methodological development and high-impact submissions toward publication, international visibility, and consolidation of a broader research programme linking mantle convection to sea level, shifts in Earth’s rotation axis called “true polar wander” (TPW), the evolution of Earth’s gravity field (as represented by the geoid), and the signature of mantle convection in the geochemistry of hotspot volcanism.

A major milestone was the publication, in Nature’s Scientific Reports, of our study on the long-term evolution of the Antarctic Geoid Low (AGL), which demonstrated how time-dependent changes to the density of mantle rocks beneath Antarctica control the strongest non-hydrostatic geoid depression on Earth. This paper significantly advanced the objectives of Work Packages (WP) 1 and 3 in the GYPTIS project, and it generated exceptional international visibility, including widespread press coverage and major online attention.

In parallel, our work on Cenozoic TPW (over the past 70 million years) and mantle-driven changes in Earth’s inertia tensor remained a central focus (as laid out in WP3). This work was presented by the project PI at the 2025 EGU General Assembly in Vienna (May 2025) and was also featured in an invited lecture at the IPGP (October 2025) and at Imperial College London (November 2025). Although the manuscript originally submitted to Nature encountered a split review outcome (one favourable, the other critical) and was not accepted there, the project progressed constructively through extensive revision and was transferred to Nature’s Communications Earth & Environment, preserving strong publication momentum.

A second major 2025 advance concerned the integration of geodynamics and mantle geochemistry. A paper led by Gabriel Johnston, the PI’s PhD student from the University of Florida, and developed during Gabriel’s six-month research visit at the IPGP, supported by GYPTIS, was posted on the open-access Research Square server and is being revised for resubmission to Nature Geoscience. This study traced southern hemisphere hotspot sources back to distinct and far-removed paleo-subduction zones and demonstrated the scientific power of combining mantle-flow reconstructions with geochemical observations, where the latter are generated by collaborators at IPGP: Catherine Chauvel and Cinzia Farnetani.

Further progress was made by GYPTIS-supported doctoral student Shayan Kamali Lima, whose work on crustal contributions to Earth’s moment of inertia and geodynamically consistent isostasy was presented at EGU 2025 and forms a major chapter of his forthcoming dissertation.

2025 confirmed the structuring effect of GYPTIS on the scientific environment at IPGP. The project continued to support the research contributions of two postdoctoral researchers, one doctoral student at IPGP, and major international collaborations with colleagues in the United States, the United Kingdom, and Australia. It also served as the scientific springboard for a new ERC Advanced Grant proposal that the PI submitted in August 2025. Although the proposal was not selected for Step 2, it received the grade A, confirming its excellent quality and validating the scientific ambition made possible by GYPTIS. A revised ERC proposal will therefore be resubmitted in 2026, ensuring continuity beyond GYPTIS.