Polar forest and atmospheric CO2 reconstruction during Earth’s last hothouse interval using multi-proxy strategies

Fossil evidence from past warm periods reveals that tropical-like forests once extended well beyond the polar circles, creating a biome vastly different from today's Arctic. Due to the absence of modern equivalents, our understanding of the adaptations and structure of these ancient polar forests remains limited and often speculative.POLARIS will investigate a polar forest from Earth's last prolonged extreme greenhouse interval—the Early Eocene Climatic Optimum (ca. 53–49 million years ago). The project aims to reconstruct canopy structure, primary productivity and atmospheric CO2 levels in which the plants thrived, using state-of-the-art palaeobotanical and biogeochemical proxies, alongside cutting-edge models. Recent advancements in the field now enable us to address these questions, and our multi-proxy approach ensures verification of results, leading to reliable findings. This research will significantly advance understanding of past polar ecosystems and elucidate the role these forests played in global carbon cycling during extreme hothouse intervals. The findings will provide valuable data that could enhance the predictive power of climate models under various future climate scenarios.The project will be based at Trinity College Dublin, Ireland, with two secondments at the Smithsonian Institution and Wesleyan University, USA. This collaboration unites world-leading experts in palaeobotany and proxy development, providing the fellow with world-class training in a variety of research techniques and transferable skills. Additionally, the fellow will benefit from networking opportunities across two continents and hands-on experiences at different institutional types. This diverse exposure will position the fellow to become a future leader in the field.