'Wobble' in Moon's orbit will cause devastating floods in the 2030s - NASA

A ‘wobble’ in Moon’s orbit will cause devastating floods in areas along coastlines in the 2030s, says a National Aeronautics and Space Administration (NASA) study, adding that US coastline will be the worst affected.

NASA Administrator Bill Nelson warned that low-lying areas near sea are increasingly at risk and will suffer the most due to more flooding events.

Nelson said that while flooding caused due to lunar cycle is common, the frequency of high tides will increase now mainly due to heating caused as a result of climate change. “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 is providing crucial information so that we can plan, protect, and prevent damage to the environment and people’s livelihoods affected by flooding,” Nelson said.

The US Atlantic and Gulf coasts frequently face high-tide floods – commonly known as nuisance floods or sunny day floods – but they were never considered a threat. For instance, 600+ such floods were experienced along the US coasts in 2019 alone. Phil Thompson, the lead author of the study that was published in ‘Nature Climate Change’, said that starting in the mid-2030s, the alignment of rising sea levels with a lunar cycle will cause coastal cities all around the U.S. to begin a decade of dramatic increases in flood numbers.

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The study suggests that the decade-long flooding event will occur every day or two and in clusters, which may last a month or even 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,” said Jane J. Lee of the Jet Propulsion Laboratory, Pasadena, California.

Why will cities experience these floodings at almost the same time?

A regular wobble in the Moon’s orbit takes 18.6 years to complete. NASA says that such a wobble is common and was not considered dangerous so far. NASA first reported it in 1728. What’s new is how one of the wobble’s effects on the Moon’s gravitational pull – the main cause of Earth’s tides – will combine with rising sea levels resulting from the planet’s warming.

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“It’s the accumulated effect over time that will have an impact,” said Thompson, who is also an assistant professor at the University of Hawaii. He said that since high-tide floods involve a small amount of water compared to hurricane storms, it is possible that people may think of it as “a less significant problem overall”. What scientists are trying to emphasis is that if flooding occurs 10 or 15 times a month, businesses will get affected and people will lose their jobs, which will lead to chaos.