A nice little summary of leap seconds and the current state of affairs. But there’s a comment at the end that I think has dropped a minus sign.
Why not just decouple the two clocks, and let them go their separate ways?
A lot of scientists do in fact feel this way. But it turns out to be really, really complicated to do that. A lot of computer systems (including satellite navigation systems) have software written a while ago, and changing that would be difficult and have unforeseen consequences. Fiddling with that may be dangerous.
Decoupling atomic time from earth rotation time requires no fiddling — you just stop inserting leap seconds into UTC. Clocks generally don’t get their cues from earth rotation, they get them from synchronization to official time, which is atomic time (in the US). It’s the fiddling — the insertion of the leap seconds into the atomic time signals — that contains the potential pitfalls.
Having countries change their official time from GMT (which is mean solar time) to UTC would be technologically trivial. It turns out that in the US this happened just a few years ago; the wording describing our time zones was changed from GMT to UTC in the America Competes Act in 2007. Even though the basis for time had been atomic time anyway, it wasn’t official until then, but nothing really changed (as far as I can tell) when the law took effect.