Oceans Rise or Fall?
Beach time of year, as good a time as any to wonder how fast the ocean is rising. In the long run, we’re locked into several feet of rise in the next century, possibly more if Antarctic glaciers accelerate.
This great figure from Discover Magazine shows how undersea “rivers” are undermining the ice shelves, accelerating their fall in unpredictable ways.
But in the near term, the ocean’s movements look surprisingly complex–giving naysayers excuses to deny the problem. For instance, the sea levels right around Antarctica will actually fall, relative to the Antarctic land mass. This happens because the mass of ice will be gone, and thus there will be less gravitational pull on the water. In addition, the land will “spring up” slightly, like the couch cushion when you get up for a snack. The net result, though, is water rising faster in farther off places like Florida and New York.
Another place ocean levels are falling is west of Mexico. The reason is weather patterns, a cyclical pattern called the Pacific Decadal Oscillation. This pattern, which takes higher math to understand, results in a decade of cooler water in the Pacific, which means denser water and lower sea level. Of course in the following period, the sea will rise double, making up for lost time.
A good reason to think about solar airplanes for your next vacation.