Oh Supreme Purveyor of Knowledge: Is sea level the same all over the world, or is the actual elevation different in some areas? — YUG, Clairemont

Truth be known, the ocean is as lumpy as an unmade bed. You’re lucky I don’t have much time, because I could really make this complicated. I’ll oversimplify it by saying that because of forces generated by our spinning globe, water tends to pile up in certain places. Around the U.S., the ocean slopes to the north; if Florida is the zero point, the slope has risen 20 centimeters around Virginia and 35 at Nova Scotia. The figures are similar from south to north along the Pacific coast. Water in the Gulf of Mexico piles up along its western shore. And, on average, the Pacific is about eight inches higher than the Atlantic. Temporary dips and hills in the ocean’s surface are created by high and low atmospheric pressure systems, ocean currents, and the moon. Two tidal bulges and dips continually circle the globe. The practical concept of sea level, used as the baseline measure for above-water elevations, is actually “mean sea level,” an average of measurements over many years. For most of us, the bumpy ocean is just a curiosity.