re: rising ocean level.
If you are fuzzy on your physics, but still interested in this stuff, I offer you to perform a simple experiment:
Take a glass of water and put an ice-cube inside it. Record the level of water. Wait till the ice-cube melts. Compare the level of water before and after.
The point is that the ice is already applying force, forcing the water out, so when it melts, no new mass appears that would force more water out.
There are some important considerations, for example, whether the ice touches down the bottom or not, but the general principle is the same.
p.s. Antarctica is different because it's a continent. So when an iceberg the size of a mountain melts there, it will make the ocean level rise.
It affects the polar bears the most because it's their habitat and when the ice melts, they are left with no surface to live/sleep on.
The point is that all of the ice is melting. Much of the ice in the North, like Antarctica, is on Greenland. The North Pole is just an early indicator of what's happening, and how bad it's gotten. It's the Canary in the mine shaft.
Greenland's ice cap that is 2-3 miles thick is disappearing. There will be a much larger than zero sum gain when all of that water is spilled into the ocean. When it does disappear, New York, LA, Seattle, Miami, the Caribbean, London... Pretty much any shoreline population will disappear as well. This is already happening right now in the Maldives.
Also, there is that pesky little matter of what happens when a lot of this water evaporates and is eventually dropped in buckets across land that is not used to nearly that much water. Weather patterns will change, causing severe droughts in what were lush areas, and causing severe floods in others.
You make it sound simple, put an ice cube in a glass of water and let it melt. Anyone that knows anything about the climate and meteorology knows that's just a vast oversimplification that's designed to quell your fears of the inevitably extremely complicated and devastating consequences of what is unfolding before our eyes,
The Franklin Expedition was trapped in ice at sea several hundred miles south of the North Pole in 1850. The ice didn't melt in the summer at their location for over 6 years, and many resorted to cannibalism. None of the ~115 men made it out alive. Just because there's daylight for 24 hours up there doesn't mean it's warm enough to melt the ice regularly.