Moon ‘oscillation’, climate change considered to be the driving force behind coastal flooding in the 2030s

July 16 (Reuters) – U.S. coasts will face increased flooding in the mid-2030s thanks to a regular lunar cycle that will amplify sea level rise caused by climate change, research by scientists shows from NASA.

A key factor identified by scientists is a regular “oscillation” in the orbit of the moon – first identified in the 18th century – which takes 18.6 years. The Moon’s gravitational pull helps drive the Earth’s tides.

In half of this lunar cycle, Earth’s regular daily tides are diminished, with high tides lower than usual and low tides higher than usual. In the other half of the cycle, the situation is reversed, with higher high tides and lower low tides.

The expected flooding will result from the combination of continued sea level rise associated with climate change and the arrival of an amplifying part of the lunar cycle in the mid-1930s, the researchers said.

“In the background, we have long-term sea level rise associated with global warming. It causes sea level to rise everywhere,” NASA team leader Ben Hamlington told Reuters. one of the study’s authors.

“This moon effect varies the tides, so what we found is that this effect matches the underlying sea level rise, and it will cause flooding specifically during this time of year. 2030 to 2040, ”Hamlington said.

Researchers studied 89 tide gauge locations in all of the United States’ coastal states and territories except Alaska. The effect of the dynamics applies to the whole planet with the exception of the coasts of the extreme north as in Alaska.

The forecast pushes back previous estimates of severe coastal flooding by about 70 years.

The study, published this month in the journal Nature Climate Change, was led by members of a NASA science team that tracks sea level change. The study focused on the coasts Americans, but the results are applicable to coasts around the world, NASA said.

“It’s a revelation to a lot of people,” Hamlington said. “This is really essential information for planners. And I think there is great value in trying to put this information from science and scientists into the hands of planners.”

Hamlington said city planners should plan accordingly.

“A particular building or infrastructure, you might want to be there for a very long time, when there might be something else that you just want to protect or have access to for a few years. “

Reporting by Dan Fastenberg; Editing by Diane Craft and Will Dunham

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