From August 18 to 25, 2025, the Baltic Earth research network held its eleventh summer school. The venue was the Stockholm University Baltic Sea Center's field station on the Swedish skerry island of Askö. A total of 14 international master's and doctoral students from across the Baltic Sea region traveled to the island to participate in lectures, seminars, and exercises on the climate in the Baltic Sea region, statistics, and marine pollution from mercury and plastic waste. This year's summer school program was organized by researchers from the IOW, the Helmholtz Centre Hereon, and the Institute of Oceanology of the Polish Academy of Sciences (IO PAN).

The summer school has been organized since 2015 at the Askö Research Station by Markus Meier, IOW expert on the Baltic Sea climate, and the International Baltic Earth Secretariat (IBES). This year, Sonja Ehlers, co-head of IBES at IOW, and Agnieszka Jędruch, co-head of IBES at IO PAN, participated for the first time. Askö is an ideal place to give students the opportunity to learn in an international and interdisciplinary community and expand their network. The summer school is primarily aimed at master's students in Earth system sciences and related disciplines, who learn how to research the climate of the Baltic Sea region and how it is changing using a comprehensive approach. In addition to the lectures, the students worked with Markus Meier to take their own measurements of electrical conductivity, temperature, and depth of the seawater using a CTD probe from a boat. The students also deepened their knowledge of fundamental climate-related processes in the atmosphere, oceans, sea ice, and on land, as well as methods of climate modeling and statistical analysis of long-term data series. In addition, the students worked in groups to write a research proposal for their own project, which they presented at the end of the summer school. The feedback from the students was consistently positive. They particularly appreciated the diversity of Baltic Sea topics taught, the international orientation, and the collaboration with students from different disciplines.