So the US, Canada, and Finland just joined an icebreaker design consortium. And I'm wondering why Finland knows icebreakers. Do they need them in the baltic?
Finland leads the world
Following World War II, Finnish companies made rapid advancements in icebreaking technology, pushing the state of the art in icebreaking design, construction, power supply, and propulsion systems. Today, Finland is a global leader in icebreaker design and construction, with most of the world’s icebreakers originating from Finnish expertise. Naturally, every single icebreaker in service in Finland has been designed and constructed locally.
Doesn't really fully answer the question, but yeah basically we have a lot of ice and shipping routes on the coastlines both west and south
But there's a chance that, cut off from the sea, the water collected wouldn't be enough to offset losses (evaporation, etc), right? Kind of like how the Mediterranean was dry when it was cut off from the Atlantic?
A telling sign is that the baltic sea gets less salty the further you go away from its connection to the north sea. That means that the water is flowing out of the baltic sea, so putting a dam there would only slowly rise the sea level.