Oliver Weisser

Title of Project

Plio-Pleistocene North Atlantic climate dynamics

Postgraduate research summary

The North Atlantic Ocean plays a crucial role in regulating the climate of Northwestern Europe and Ireland through the Gulf Stream, which brings warm and moist air from lower latitudes. The Gulf Stream is part of a larger system of ocean currents known as the Atlantic Meridional Overturning Circulation (AMOC), which is influenced by a sensitive balance between ocean temperature and salinity. Recent studies suggest that the Gulf Stream might be slowing down due to global warming, leading to potentially drastic climate changes.

My research focuses on understanding how the AMOC behaved during the middle Pliocene Warm Period (mPWP), about 3.3 to 3.0 million years ago, which is the most recent period with climate conditions similar to those predicted for our future. By studying this period, I aim to gain insights into how future changes in the AMOC could impact climate, especially in Northwestern Europe.

During the summer of 2023, the IODP Expedition 395 collected high-quality sedimentary records from the North Atlantic. These records will allow me to study past climate changes in great detail, down to sub-millennial scales, which are relevant for understanding changes over societal timescales.

The main goal of this project is to reconstruct high-resolution temporal variability of the AMOC during the mPWP. This will help improve future climate projections and provide valuable data for climate models. My first step is to refine the age models for the sediment cores collected, ensuring accurate dating. Then, I will select the best intervals for detailed study based on the highest temporal resolution achievable.

Additionally, I will investigate volcanic ash layers found in the sediment records to explore potential correlations with past climate changes. These findings could provide further insights into the complex interactions between climate and geological processes.

Name of supervisor

Dr. Matthias Sinnesael

Postgraduate personal details

During my bachelor’s research in Münster, Germany, I used multiple simulations to identify how meltwater influx into the North Atlantic affects the stable isotope composition (²H and ¹⁸O) of recent precipitation in Europe and North America. This was my first exposure to the North Atlantic and the Atlantic Meridional Overturning Circulation (AMOC). In my master’s, I expanded on these findings by attempting to detect similar changes in the recent sedimentary record. While sampling challenges limited the results, the work provided insight into why tracing recent climate changes in sediments is extremely difficult.

During my PhD, I am excited to explore how my knowledge of the modern North Atlantic and AMOC can be applied to understanding the Atlantic during the Mid-Pliocene.

Project Start Date

September 2025

Funding

Government of Ireland Postgraduate Scholarship

Publications

Weisser, O., De Vleeschouwer, D. & Strauss, H. The influence of climate change on the 18O and 2H signatures of meteoric waters in Europe and North America. Model. Earth Syst. Environ. 10, 6917–6930 (2024). https://doi.org/10.1007/s40808-024-02137-6

Contact Details

Email: weissero@tcd.ie