Baltic Breakfast: Ocean warming – from global change to Baltic Sea impacts
Global warming is already having an impact on the oceans, with mean water temperatures rising and heatwaves becoming more frequent. This has a direct impact on marine organisms, but also amplifies existing pressures such as eutrophication.
Ocean warming is also changing stratification — the way waters of different density are layered in the ocean. Changes in stratification can alter the vertical exchange of heat, nutrients and oxygen, with consequences ranging from the global ocean circulation to oxygen conditions and ecosystems in regional seas such as the Baltic Sea.
Since pre-industrial times, the global average temperature of the ocean surface has risen by approximately 0.9°C. However, the Baltic Sea – like other polar and temperate marginal seas – has warmed at approximately twice the rate of the global ocean average and is experiencing more frequent, longer-lasting and more intense marine heatwaves.
As marine heatwaves are defined in relation to local temperature extremes, the important question is not whether they occur, but how their characteristics – frequency, duration and intensity – have changed over time and across regions and how they affect the ecosystems. Heatwaves can trigger abrupt ecosystem change and mass mortality events – making them a critical, and often underestimated, dimension of climate change impacts.
Welcome to a breakfast seminar on the global situation regarding ocean heating, as well as the situation in the Baltic Sea, and what has to be done!
Speakers
Fabien Roquet, Professor in Physical Oceanography at the Department of Marine Sciences, University of Gothenburg
Norman Göbeler, PostDoc Reseacher at Tvärminne Zoological Station, Helsinki University
Moderator: Gun Rudquist, Head of Policy at Stockholm University Baltic Sea Centre
Practical information
The seminar will take place on Wednesday, 21 October 2026 from 08:30 to 09:15, at the Scandic Klara hotel on Slöjdgatan 7 in Stockholm. A vegetarian breakfast will be served from 08:00.
Physical participation requires registration.
The seminar will also be livestreamed. A recording can be watched afterwards. No registration is needed to watch the livestream.
Questions?
To ask questions of the participating researchers, please email us at ostersjocentrum@su.se or visit sli.do and use the code #22102.
Reading
Read our new policy brief about marine heatwaves, published in October 2026:
Action is needed to mitigate the impacts of Baltic heatwaves (webb text)
Action is needed to mitigate the impacts of Baltic heatwaves (English)
Åtgärder krävs för att möta värmeböljorna i Östersjön pdf, 2.4 MB. (Swedish)
Itämeren lämpöaaltojen vaikutusten hillitseminen edellyttää toimia (Finnish) pdf, 2.4 MB.
ABOUT BALTIC BREAKFAST
Baltic Breakfast is a series of short breakfast seminars/webinars organised by Stockholm University Baltic Sea Centre. Their aim is to present the latest knowledge about issues of central importance to the Baltic Sea environment. The webinars are addressed to people in different sectors working for a sustainable development in the Baltic Sea region and everyone interested in environmental issues of the Baltic Sea.
Most Baltic Breakfasts are held in Swedish, but sometimes they are targeted at an international audience and held in English.
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Last updated: 2026-10-20
Source: Stockholm University Baltic Sea Centre