The study, conducted by NASA and the University of Hawaii, examined ongoing sea-level rise and the dire situation coastal cities will face during the next lunar shift, or “wobble,” CBS News reported.
The so-called wobble that occurs in the moon’s orbit is a naturally occurring phenomenon that was first documented in 1728 and happens every 18.6 years — resulting in changes in the tides.
“In half of the Moon’s 18.6-year cycle, Earth’s regular daily tides are suppressed: High tides are lower than normal, and low tides are higher than normal,” NASA said.
“In the other half of the cycle, tides are amplified: High tides get higher, and low tides get lower. Global sea-level rise pushes high tides in only one direction – higher. So half of the 18.6-year lunar cycle counteracts the effect of sea-level rise on high tides, and the other half increases the effect.”
While the wobble itself doesn’t cause catastrophic damage, scientists found the next high-tide floods will be much worse when taking rising sea levels due to climate change into account, the outlet reported.
Researchers mapped the National Oceanic and Atmospheric Administration’s sea-level rise scenarios, flooding thresholds and astronomical cycles and found flooding in coastal locales could be much worse come the 2030s when the next “wobble” is set to begin, the outlet said.
The rising waters are expected to cause serious damage to infrastructure and displace coastal communities.
In 2019, NOAA clocked over 600 catastrophic floods and researchers predict there’ll be three to four times that in the mid-2030s after another decade of rising sea levels.
“Low-lying areas near sea level are increasingly at risk and suffering due to the increased flooding, and it will only get worse,” NASA Administrator Bill Nelson said.
“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.”
In the US, Hawaii and Guam are most at risk for these effects but rising waters are already expected to displace over 100 million people worldwide and leave huge swathes of coastline uninhabitable before the year 2100.
While hurricanes bring more floods than high tides, scientists said the frequency of the floods will be the true danger.
“It’s the accumulated effect over time that will have an impact,” said Phil Thompson, the lead author of the study, which was published in the journal “Nature Climate Change” in late June.
“If it floods 10 or 15 times a month, a business can’t keep operating with its parking lot under water. People lose their jobs because they can’t get to work. Seeping cesspools become a public health issue.”