Big Numbers Don't Lie!
Some people are easily panicked by big numbers taken out of their proper context. Take "climate change" which was once called "global warming."
Recent NASA and subsequent media stories have said this about Greenland and Antarctic ice: "The two regions have lost 6.4 trillion tons of ice in three decades; unabated, this rate of melting could cause flooding that affects hundreds of millions of people by 2100."
Big, scary number there! 6.4 trillion tons lost! Our coastal cities are doomed!
But how much ice is there in Antarctica? Wikipedia reports it as 26,500,000 gigatons. Throw in the ice in Greenland, and the total ice loss each year is a nearly undetectable three ten-thousandths of one percent (0.0003%) of the world's ice mass. Despite statements of certainty, this loss is well within the range of measurement error.
So, how much has the sea level risen? Compared to when? And where would it be measured? The continents themselves raise and lower over time because they're floating on the mantle, with tectonic plates slipping over and under each other.
The fact is that while there are ancient cities divers can explore underwater in the Mediterranean and Caribbean, the water didn't rise by tens or hundreds of feet. Rather the land sank due to volcanoes and other dramatic local changes.