By the middle of the century the Arctic Ocean may be open water during summer, even with moderate CO₂ emissions.

KUNNGJØRING PRØVEFORELESNING Institutt for geovitenskap Det matematisk-naturvitenskapelige fakultet Universitetet i Bergen Ph.d.-kandidat Wanyee Wong holder prøveforelesning over følgende oppgitte emne for ph.d.-graden: Constraining the chronology of ocean sediments – an overview of available approaches and their advantages and limitations Tid og sted: Fredag 19. september 2025, kl. 13.15 Auditorium 4, Realfagbygget Komité: Professor Ulysses Silas Ninnemann, Institutt for geovitenskap (leder for komiteen) Professor Anna Nele Meckler, Institutt for geovitenskap Førsteamanuensis Bjarte Hannisdal, Institutt for geovitenskap Adgang for interesserte tilhørere. VELKOMMEN!

Speaker: Zhetao Tan from the Laboratoire de Météorologie Dynamique, École Normale Supérieure (LMD/ENS). Abstract Global climate change has triggered widespread shifts in the ocean’s physical and biogeochemical state. The essential ocean variables (EOVs), such as temperature, salinity, oxygen, and pH, known as climatic impact-drivers (CIDs), provide critical risk information for climate impacts across ocean sectors. Yet, a global three-dimensional view of long-term compound changes and their underlying physical processes remains limited, largely due to limitations in data availability (e.g., data quality, data coverage, and data processing techniques). This presentation will first introduce recent advances in observational data processing techniques developed by the speaker and his collaborators over the past five years, including improved quality control, systematic bias correction, and spatial mapping. Using these state-of-the-art in-situ and gridded products based on the advanced data processing techniques, the presentation will show the examination of long-term compound CIDs in the global scale (put temperature, salinity, dissolved oxygen, and pH together in the same framework), identify the climate hotspots of the above concurrent change, and assess when and how these compound signals emerge. Results reveal a large-scale and deep-reaching compound ocean state change triggered by global warming, most prominently in the Atlantic Ocean. Finally, as a region study to understand the physical processes of the above compound climate change, the presentation will report recent findings that the South Atlantic upper-ocean water masses are responding to compound climate change over the past 45 years through distinct but connected processes: Air-sea surface-driven exchanges dominate the long-term warming and salinization changes in the Surface Water (SW), vertical displacement shapes the changes in the volume-expanded South Atlantic Central Water (SACW), and advective anthropogenic heat redistribution governs the warming and thinning changes in the core Antarctic Intermediated Water (AAIW). Speaker information Dr. Zhetao Tan is a post-doc fellow at the Laboratoire de Météorologie Dynamique, École Normale Supérieure (LMD/ENS), working on the OCEAN:ICE project funded by Horizon Europe. His research interests include physical oceanography, operational oceanography, and ocean climate change impact, with a particular focus on ocean observations and data quality improvements, water mass and ocean circulation, ocean compound climate change. Particularly, he mainly focused on the study of ‘climate impact-drivers’ (e.g., temperature, salinity, dissolved oxygen etc.) which connect physical ocean changes to broader climate impacts. He hold his Ph.D from the Institute of Atmospheric Physics, Chinese Academy of Sciences (IAP/CAS) in 2024. He is also a member of the International Quality Controlled Ocean Database (IQuOD), and the SOOP-XBT data management team (XBT-DMT).

Bjerknes Annual Meeting (BAM) Monday 29th of September 2025 Venue: Scandic Bergen City, Håkonsgaten 2-7 Main theme: Science for Society 08:00 09:00 Registration and coffee 09:00 09:10 Welcome and introduction to BAM by Director Kikki Kleiven How do we interact with society? Examples from the four research themes 09:10 09:40 How the Global research theme interact with society “From data to decisions: navigating usable climate services” Talk by Jesse Schrage on seasonal forecasts and climate services in Eastern Africa (ARCS and ACACIA project) 09:40 10:10 How the Polar research theme interact with society “Science & Society –The Greenland Sessions” Talk by Lars Henrik Smedsrud from Climate Narratives 10:10 10:30 Coffee break 10:30 11:00 How the Hazards research theme interacts with society “Boosting impact through societal engagement: Examples from Vestland County". Talk by Marie Pontoppidan "Estimating future runoff in ungauged catchments in Norway using machine learning". Talk by Kamilla Wergeland 11:10 11:40 How the Carbon research theme interacts with society “How, why, and to what avail? A travel log from my journey into the [sometimes murky waters of the] science-policy interface” Talk by Vigdis Vandvik 11:45 12:30 Lunch How to make our strategy relevant for Bjerknes members and society? 12:30 12:45 Results of the Bjerknes Centre internal perception mapping presented by Gudrun Sylte 12:45 13:00 President of the European Academies` Science Advisory Council (EASAC) Lise Øvreås on the role of science in policymaking, science diplomacy and how to get politicians to "care" about science, and how to build trust between science/researchers and politicians. 13:00 13:30 Break-out groups Science for society 13:30 14:00 Invited talk by Professor Thomas Jung on The Future of Climate Modelling: Emerging Directions 14:00 14:35 Coffee break 14:35 14:50 Climate Futures at mid-term by Iselin Medhaug 14:50 15:05 Scandinavian Centre for Mountains in Transition by Jostein Bakke 15:05 15:20 Presentation of the new national research school Climate-Informed by Lea Svendsen 15:25 15:45 Speed presentations of posters 15:45 17:45 Poster session 18:00 Dinner