The stalictites are probably 10s of millions of years old. The...

The stalictites are probably 10s of millions of years old. The oceans have been far higher and lower than they are now.

But we can't think in terms of millions of years. or 10s of millions!  

A thousand years is probably how long the oceans will be higher for after the CO2 already released. Or 10s of thousands. We are talking about geophysical scales and we are changing things forever. 

We don't have to use fossil fuels for our energy needs and set in motion changes that will change the world forever ie. a hundred thousand years.

There are alternatives !