A record-breaking warm spring in the North and Baltic Seas, with the North Sea experiencing its warmest spring since 1997, according to the German Federal Maritime and Hydrographic Agency (BSH).
The agency measured exceptionally high water temperatures in the North and Baltic Seas in March, April and May of this year, with the North Sea as a whole experiencing the warmest spring on record since the beginning of data collection in 1997. The German Baltic Sea also recorded record temperatures, with a marine heatwave lasting as long as never before in Kiel.
“The spring temperature of the North Sea rose to an average of 8.7 degrees, the highest since the beginning of our current data in 1997” said Tim Kruschke, head of the Marine Climate Questions department at the BSH. This is 0.9 degrees above the long-term average from 1997 to 2021. “Almost the entire North Sea was at least 0.5 degrees warmer than usual, with significant deviations upwards.”
The greatest deviations were found in the eastern North Sea off the Norwegian and Danish coast, where temperatures reached up to 2 degrees above the long-term average. This is the highest spring temperature recorded by the BSH for large parts of the northern and central North Sea since 1997.
In the German part of the North Sea, surface temperatures were also significantly above the long-term average, ranging from 0.8 to 1.5 degrees. Depending on the location, this was the fourth to sixth warmest spring since 1997.
The Baltic Sea, in turn, had an average spring temperature of 5 degrees, the sixth warmest spring since 1997, with a 1-degree deviation from the long-term average. Regional differences were evident, with the outer north being slightly cooler than the average, while the south was significantly warmer.
In the southwestern part of the Baltic Sea, which includes the German waters and the Danish islands, the temperatures were more than 2 degrees above the long-term average, making it the warmest spring on record since the beginning of the current data in 1997.