The older effect is the earth getting less flat and more spherical. The newer effect is water moving from the poles to the equator.
What is the Ice Age Effect?
The Earth is growing more spherical because 20,000 years ago we had a lot more ice at the poles. When ice sheets were at the poles they kind of squished the Earth from both poles and the Earth flattened a little bit. When those ice sheets melted, that flattening started to rebound and we’re becoming spherical, so our spin rate should be increasing, like a ballerina or a figure skater. The ice age correction is a speeding up of the rotation rate.
In both cases, polar ice is melting. Since it's claimed that this melting has two opposite effects, it's unclear how to separate one effect from the other.
- The recent melts have only been of a relatively small mass of ice, and the two effects on rotation aren't linear,
- There hasn't been enough time for the Earth's shape to have changed in response to the recent ice melts.
I'll admit I'm a bit suspicious, though.
This article is fascinating...this man--Jerry Mitrovica--is obviously a genius...the techniques used to arrive at the conclusions he's reached...just wow...
My takeaway is that the gravitational attraction of ocean waters that the Arctic, Anarctic and Greenland ice sheets currently provide will diminish as those ice sheets melt...
This means that water previously attracted to those ares will move south...
The polar regions will experience lowered sea levels...the temperate regions will experience a rise well beyond what was earlier predicted...
Sobering news...