Back in the day, I used to measure tiny things - white blood cells, viruses, stuff like that. I worked with people who measured molecules.
Now, I’m not confident in a method that measures variations in the level of ALL THE WATER ON EARTH in millimeters, while said water is constantly in motion and subject to gravitational forces from the sun and the moon, as well as constant variance in surface atmosphere pressure.
To boil it down, the whole thing sounds like BS.
That’s exactly what it is. A scam by scientists to get more funding and a scam by politicians to control people.