A journey through time - 3 June 2018

A month already that we are in this unusual anticyclonic pattern bringing tropical temperatures to Sweden since the beginning of May, currently being above 30°C. Very unusual, but enjoyable, even though it comes of course with flocks of mosquitoes and other disagreements. No complains thought :-), so unusual, so enjoyable. I spent part of the weekend preparing for our Finland adventure in four weeks from now. Lots of small and bigger things to do, just the routine. Yet on Sunday, I decided to have a sail through time and moore in Anundshög where is located the largest stone ships in Sweden. Five of them indeed.

This was the start of a journey through time...

The largest of the stone ships here is 53 metres long by 16 metres wide. At the centre is a stone representing the mast. The picture below is a "little planet" captured from this particular "centre of the world" place. Such a feeling standing there.

Few kilometres away stands one of the oldest church in Sweden, dating 12th century. Closed however when I reached it.

Amazing forested area around here. A bit rock'n roll for the bike, but so refreshing with so many young "björk" trees.

So why these boats are so far from the sea nowadays? Just because the land has been "rising-up" constantly since the ice-age, on a rate of around 1 cm per year, meaning, one metre per century.
The land under the mälaren has been popping-up at that rate for now, resulting in nice coves and harbours getting dry in a matter of a generation. This resulted in most village displacement over the centuries in order to keep access to the open sea.

The history of the Baltic sea is very interesting. A very interesting history of the Baltic can be found in English at this Danish website. To make it short, the Baltic sea was first the Baltic lake, 15,000 years ago, when most of Norway and Sweden were covered by a one kilometre thick glacier draining in the Baltic lake. Then, around 11,000 years ago, as the glacier started to melt, the lake connected with the sea and became the Yoldia sea. The connexion was through a straight located in the middle of Sweden along the big lakes and the Göta canal of today. However, as the glacier was continuing to melt, the land rose and around 10,000 years ago, it became again a lake called the Ancylus lake. You follow me? Finally, around 5 to 7,000 years ago, the Ancylus lake found its way to the sea between Sweden and Denmark of today and became a sea again, the Litorina sea...

For centuries in Sweden, the big question was whether the sea level was dropping or the land level rising. In 1700, the idea was that the Baltic sea level was decreasing because more water was getting out through the Danish straight than running from the rivers in the Baltic. One generation after, Celsius (ye, the Swedish scientist known for his temperature scale) got the idea to go around Sweden and document the position of seal rocks of the coast. In Iggön, the found one interesting seal rock where local fishermen had documented over the generations on which part they could hunt seals resting on the rock. He calculated the rate of decrease to be 1.4 cm per year. Linnaeus (Linnée, another famous Swedish scientist) confirmed the finding by Celsius by studying the ridges along the Gotland coast. Then two scientists having noted changes in the bed rocks in mines suggested that it was probably the land rising rather than the sea dropping. Sweden started recording the sea level in different part of the Baltic, and was able to conclude around 1830 that indeed, it was the land rising, in fact faster in the northern part of the Baltic compared to the southern part where the rising is negligible. There is book written about it called "The Changing Level of the Baltic Sea during 300 Years: A Clue to Understanding the Earth".

Stockholm has the oldest recording of sea level in the word, starting from 1774. On Skeppsholmen, you still can see the first station recording sea level in Sweden. A very small octogonal house along the seaside.
 

The plan on the information plate shows that the measurement works through a connection with the sea. The recording is done by using a floating device inside the house. Yet, as you can see on the picture, nowadays, the connexion with open water is threatened, and I wonder how long this station will remain connected with the sea. Hopefully, there are hundred of functioning stations in Sweden, so the death of this one in Stockholm should not affect our ability to monitor the further land rise in the Baltic. 

Information on the Mälaren uplifting station in Stockholm

Getting around Skepsholmen after visiting the sea level station, I came across this wreck becoming visible as the sea level decreases, in fact as the land level increases. 

Well, not far away is the construction site for new boats in Stockholm built the ancient way. Quite nice looking through the plastic sheeting. Reassuring that the tradition is alive...