From the we-bet-you-didn’t-know-this department: A report from NASA (here; in laymen’s language here) reminds us that there are irregularities in the moon’s orbit (“wobbles” to the common person) on an 18.6 year cycle that affect earth’s tides, with half of the cycle producing lower-than-normal tides, and the other half resulting in higher-than-normal ones. This has been known since the 18th century, so it’s not exactly new news.
What is new, apparently, is that the higher-than-normal phase of this “wobble” that will occur in the 2030’s is going to coincide with the climate-change driven sea level rises . The combination may produce regular devastating coastal flooding:
Led by the members of the NASA Sea Level Change Science Team from the University of Hawaii, the new study shows that high tides will exceed known flooding thresholds around the country more often. What’s more, the floods will sometimes occur in clusters lasting a month or longer, depending on the positions of the Moon, Earth, and the Sun. When the Moon and Earth line up in specific ways with each other and the Sun, the resulting gravitational pull and the ocean’s corresponding response may leave city dwellers coping with floods every day or two.
“Low-lying areas near sea level are increasingly at risk and suffering due to the increased flooding, and it will only get worse,” said NASA Administrator Bill Nelson. “The combination of the Moon’s gravitational pull, rising sea levels, and climate change will continue to exacerbate coastal flooding on our coastlines and across the world. NASA’s Sea Level Change Team is providing crucial information so that we can plan, protect, and prevent damage to the environment and people’s livelihoods affected by flooding.”