Ocean current conveyer belt

[elte]

The great ocean conveyer belt,  also called the thermohaline circulation, is what keeps much of the Old World warm in the winter.   It has occurred to me why it it is where it is.  Alaska and Russia are so close together that they block potential flow on that side of the world.  The temperature gradients between the Arctic Ocean and more southern waters practically have only the space between North America and Europe to try to reduce themselves.