This year, an unusual weather phenomenon has caused a dramatic decrease in water levels in the Baltic Sea, with water volumes equivalent to nearly two lakes Vänern being pushed out. This record low water level, attributed to a high-pressure system that has stalled over Sweden and persistent easterly winds, is seen as a potential benefit for oxygen-depleted seabeds. Oceanographer Jörgen Öberg from SMHI comments that while this event is rare, it offers a glimmer of hope for the marine ecosystems affected.

The phenomenon, described as a high-pressure blocking effect, has kept cold weather over Sweden for several weeks. Along with the easterly winds, this has expelled large amounts of water from the Baltic Sea through the Öresund Strait and the Danish belts. Estimates suggest that up to 300 cubic kilometers of water have been displaced, highlighting the significant impact of this weather pattern. Even though water levels rose during the storms Johannes and Anna around New Year's, the level of decrease observed this year is unusual and concerning.

The fluctuations in water levels in the Baltic Sea are generally expected; however, the extent of the decline witnessed this year has not been seen frequently in historical records. The data from over a century of measurement in the region shows the extent of this anomaly. As discussions continue about the implications of this weather phenomenon, questions arise concerning climate patterns and their long-term effects on marine ecosystems in the area.