The latest scare about man-made global warming is that it is slowing the Earth’s rotation.
The reasoning is that ice melting at high latitudes results in the meltwater moving to lower latitudes, which increases the moment of inertia which slows rotation.
Although this is theoretically correct, the amount would be so tiny as to be immeasurable. However, the scientists who announced this claimed to have found a measurable amount via satellite.
There are all kinds of problems with this.
First of all, angular momentum is conserved, so when the ice reforms, the “lost” rotational velocity will return. But again, the amount would be infinitesimally small, so the whole thing is simply lunch conversation at the physics lab.
OK, but what about the measured amount? The earth’s axis wobbles on several periods of rotation and this probably would cause tiny but measurable change in rotational velocity, but again, angular momentum is conserved and the lost velocity will return when the axis straightens.
Examples: When an ice skater wants to increase the spin rate, they pull in their arms, and when they want to slow the rate again, they extend them. A spinning child’s top will visibly slow down when it wobbles but speed up again when it straightens.
The old argument of sea level rise was also mentioned: As the ice melts, sea level increases, causing flooding. The problem with this is that the ice that (periodically) melts is almost all floating ice, which has no effect on sea level either way.
The big ice fields on Greenland and Antarctica that would affect sea level are stable or slightly increasing.
So what does this say about our scientists? Are they woefully ignorant of basic physics, or are they trying to con us? Unfortunately I think it is the latter.
This whole global warming issue is dying, but pride is causing these people to grab at straws.
Dick Riethmiller
Pagosa Springs
