Just why is everyone so scared of the Arctic melting?

I'm serious. Even if every last bit of Arctic ice melted, it wouldn't affect sea levels to any noticeable degree. I'm including Greenland's ice in this. The floating ice at the arctic would have approximately 0 effect due to the fact that it's ALREADY IN THE WATER. When ice melts in a cup of water it has no effect. This is because the ice is parially sunk in the water, which forces the water level up. When the ice melts, it stops forcing the water up but provides more water from itself, which keeps the water level at the same height. As for Greenland's ice, it would turn into a giant lake due to the topography of the area (specifically, it's in a giant bowl created by its own weight). Now of course there is other ice in the area that could affect sea level, but only to a minimal extent. As for Antarctica, it's getting colder. In other words, the worst we have to fear is new shipping lanes, a rise of a few inches, and easier oil drilling. Shudder.