6th Baltic Earth Colloquium on Marine Heatwaves

Marine Heatwaves in the North Sea / Baltic Sea - Causes and Consequences

Matthias Gröger, Leibniz Institute of Baltic Sea Research

Global warming is likely to increase the risk for marine heatwaves (MHWs). Recent research has documented an increase in the frequency of MHW days over the last three decades in both the North Sea, and the Baltic Sea. Contrary, the expected thermal intensification and prolongation of MHWs is difficult to deduce because of the rare nature of these phenomena and the associated sampling error this results in. Due to the thermal inertia of the ocean, MHWs respond slowly to meteorological conditions but on the other hand, once they are formed, they can persist a long time after favorable conditions vanished. Hence, the temporal delay between cause and effect challenges the identification of the MHW drivers.

In the first part of this presentation a solution for this problem is provided and the dominant drivers and prevalent meteorological conditions will be identified. In the second part, the effects of climate change and MHWs on the marine ecosystem are assessed. More precisely, we will investigate the likelihood of hypoxia in the coastal zone in a future warmer climate. Finally, the effect of MHWs on the early life stages of the western Baltic herring stock is analyzed for the historical climate, as well as for the future following the climate targets of the United Nations Framework Convention on Climate Change (Paris, 2015).

The Colloquium will take place online on Monday 2 December via zoom at 15:00 Stockholm, 16:00 Helsinki time.

A short registration is necessary to receive the participation link.

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