Worldwide differences in sea level
Sea and mountains photo by Argenberg
I just journeyed through the Panama canal, and learned that there’s a difference in sea level from one side of Central America to the other, how does that relate to the height of mountains above sea level?
Sea level is different across continents and around the world. That’s because the mass that makes up Earth’s crust isn’t evenly distributed, and where there’s more mass, there’s a greater gravitational pull.
Sea level is also elevated over a seamount, or underwater mountain, because the excess mass causes water to pile up there. The biggest relative drops in sea level are usually located near ocean trenches. But largest known dip in sea level, a depression of over 100 meters in the Indian Ocean, has a source that’s yet to be identified.
So, when you describe the heights of mountains or differences in sea level from one place to another, you have to say with respect to what reference surface. In the last few years, new equipment and satellite radar altimeters have let scientists pinpoint the center of Earth’s mass. It has become possible to measure sea level in a globally uniform reference system – and it’s likely that sea level will require a new definition.
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