A lot of people know about the Northwest Passage from Newfoundland to British Columbia. It opens up every 20 years or so and then closes down. A matter of currents and wind more than temperature.
The Northeast Passage is not as well known -- from the East coast of Russia and Asia, it extends north over the top of Russia and ends in Europe. This passage has been in commercial use for about ninety years -- the Russians use huge icebreakers to keep it open.
Well, they seem to be having a bit of trouble. From Breitbart/AFP:
More than 50 ships stuck in Baltic Sea ice: maritime authorities More than 50 ships, including large ferries reportedly carrying thousands of passengers, were stuck in ice in the Baltic Sea Thursday evening, and many were not likely to be freed for hours, Swedish maritime authorities said.
Explain to me again this theory of yours... Something about Global Warming?
For the final word on melting Ice Caps, here is a dissertation from renowned climatologist Herbert Khaury: