Someone took the cap off.
Earth's oceans are slowly emptying, and water is running out under the Earth's crust: this is the outcome of research conducted by two Norwegian scientists from the University of Oslo and mentioned by the site New Scientist.
The oceans are sinking under the Earth's mantle, but the process is so slow that we won't see the seas rise less due to climate change.
According to this research, published in the magazine Geochemistry, Geophysics, Geosystems this 'spill' began to slow down around 150 million years ago, when the super continent Pangea broke up.
It will take quite a while to empty the tub
At the current speed (or it would be better to say slowness), they say researchers authors of the study, the oceans will dry up in 12 billion years.
There is not much to worry about, therefore: also because for that date also the Sun will have its beautiful problems.