This has been kept simple intentionally.
The first reason is that I don’t know enough about the math to do it any other way. Even if I did, I would never fit it all into a single blog post.
The second reason is that you will understand it easily.
Consider a metal bar connected to an infinite heat sink at 0C at one end, and the other to an infinite heat source at 100C.
At any point on the bar between the ends, the temperature will be function of distance, and at dead centre the temperature will be 50C.
Now consider the same metal bar, with infinite heat sinks at 0C at both ends, and an external source of heat in the middle at 50C. It could be shown like this –
The same principle applies – at the mid-point of each side, the temperature will be 25C.
Now, let’s see what happens if the right-hand end were disconnected from 0C, and left to float. We could represent it thus:-
Now, the left-hand end temperature is fixed at 0C, as before, but the right-hand end is floating and is not so easy to define. It will, however, lie somewhere between 0C and 50C+. The mid-point will take on a new higher value, as a result of the right-hand end floating. If the mid-point changes to a higher temperature, all temperatures to the left will increase in line.
Ok, you say, sounds reasonable. So what?
Well, the same principles that I have just discussed apply to this:-
and currently the human race is busy destroying the 0C temperature sink at the North Pole. When this happens, and I think it is only a matter of time, I estimate that most of the Northern hemisphere will become uninhabitable, and the available area for habitation in the Southern hemisphere will be reduced.
I would prefer the Northwest Passage to remain covered with ice all year round!