|A view of the Arctic Ocean from 1849|
Once people thought we live on a flat earth - which makes sense if all you see of the world is what is out the window. It must have taken a lot of guts along with a dose of extreme self confidence to be among the first who went against this belief. One example is Christopher Columbus, who made the assumption the earth was round when he sailed westward to find China - fortunately for him and his crew, he was right (about the roundness of the planet, but not the distance to China).
From the window of a commercial flight anyone can see earth’s curvature by looking at the horizon. With pictures from space, we can conclusively show the earth is round. Contrary to this evidence, flat earth societies have not disbanded. Why do they hold onto the idea of a flat earth?
Another idea that persisted despite contrary evidence was an ice-free polar ocean, that the only ice was around the edges and once you broke through this ice it was clear sailing. This idea dated back to the 16th century, and perhaps earlier. Joseph Moxon, a royal hydrographer working in the 1660s, continued promotion of this ice-free idea attributing it to the 24hr a day solar heat melting the ice in the summer. He also theorized that ice only formed near landmasses where the water was fresher - an idea that morphed over the next 100 years into seawater being unable to freeze by its nature (which is easy to disprove in a lab experiment).
Since an open polar sea presented a potentially lucrative short-cut, expeditions were commissioned to break through the ice and find the open sea beyond. The all failed, some more spectacularly than others. Franklin tried to break through on one of his early missions, failed and went home, while the R/V Jeannette tried, got frozen into the ice and ultimately crushed. Still more ships were sent until Nansen tried walking to the pole and found ice all the way.
The idea of an open Arctic Ocean hasn’t gone away even after it was proven to be covered in multi-year ice instead the idea has morphed into one based on science. In the 1970s the idea reared its head again when an irrigation proposal was made to divert several major Siberian rivers that normally flow into the Arctic to central Asia instead. Beneath the layer of cold Arctic waters is a layer of warmer Atlantic water. This deep warmer water is insulated from the surface because the cold water above is fresher, meaning it remains less dense even though it is colder than the water below. If less freshwater goes into the Arctic Ocean, the cold top layer could become saltier and sink below the warmer water. The warm water then could influence the surface and melt the ice.
Another way the Arctic Ocean may loose its ice is through global warming. The polar ice cap is likely to melt completely in the summer in my life time - making a shipping shortcut across the pole a seasonal possibility.
Flat earth and open polar seas were both incorrect ideas that were held onto even when contrary evidence was found. This planet has been conclusively shown to be a sphere (or, more precisely an oblate spheroid), however, an open polar sea may become a reality.
Image is from here