Sea Level

Mount Whitney, the tallest mountain in the lower 48, rises 14,505 feet above sea level. Or does it?

According to science, the mean sea level is changing. The glaciers found at the poles are melting, despite what Republicans tell voters. The sea level is rising. If all the glaciers melt, the sea will rise 230 feet, and Healdsburg will be under water.  

I think the oceans are flat--and I have inspected both the Atlantic and the Pacific. But scientists disagree. They claim that even in the absence of waves, the oceans have, on their surfaces, small hills and valleys. 

Astronauts argue that our planet is a flattened spheroid. For some reason this shape causes a depression of 348 feet in the sea level of part of the India Ocean. (That must be wrong.)

Of course, land also rises and falls over time. Mt Whitney is rising about an inch every 20 years. In 240 years it will be 14,506 feet above mean sea level, depending on what the sea level becomes. 

I have read that winds, currents, river discharges and variations in gravity and temperature make local sea levels differ.  High and low pressure areas in the atmosphere change the surface level of the oceans. 

The sea level off San Francisco is about 8 inches higher than the sea level off Boston. Of course it is.