The slides just say "predictable speedup starts 2020" but don't really explain it, except for a vague reference to the "19 year metonic cycle".
The question I really wanted answered going in is: why is the Earth's rotation speeding up since 2020?
If we look at 19y intervals in the past at the UT1-UTC plot, we can see something unusual around 2000, but nothing really at 1980. And leap seconds started in the 70s! So this is a fascinating set of slides but the question is still frustratingly open for me.
The question I really wanted answered going in is: why is the Earth's rotation speeding up since 2020?
If we look at 19y intervals in the past at the UT1-UTC plot, we can see something unusual around 2000, but nothing really at 1980. And leap seconds started in the 70s! So this is a fascinating set of slides but the question is still frustratingly open for me.