A study conducted by NASA and released this week is warning of a “dramatic” increase in flooding along U.S. coastal regions beginning in the mid-2030s due in part to a “wobble” in the moon’s orbit.
Researchers predict there could be a “rapid” increase in the frequency of flooding at high tide along coastal regions, according to a report published in the Nature Climate Change journal, produced by the NASA Sea Level Change Team at the University of Hawaii.
The report cites the “wobble” of the moon’s orbit, something that happens regularly every 18.6 years and causes extremely high and low tides, as a factor in potential flooding.
The other factor, according to NASA, involves an increase in global sea level. The study pointed out that higher sea levels have begun to cause some flooding at high tides. The combination of the moon’s wobble and the higher sea level will push high tides higher, the study says.
“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,” NASA explains.
NASA Sea Level Change Team leader Ben Hamlington, one of the study’s co-authors, said that flooding is more likely because the factors that are making it happen now will only be worse in the future.
“We’re getting closer and closer to the flooding thresholds or tipping point in these coastal locations,” said Hamlington. “The same variability in the past that didn’t cause flooding is now going to cause flooding.”
The coastal regions of the U.S. mainland will feel the effects of the flooding, the study said, with Alaska’s coast being spared, but only for a period of time.
“The higher seas, amplified by the lunar cycle, will cause a leap in flood numbers on almost all U.S. mainland coastlines, Hawaii, and Guam. Only far northern coastlines, including Alaska’s, will be spared for another decade or longer because these land areas are rising due to long-term geological processes,” NASA said Wednesday.
Water overflowing into coastal communities during high tide is a common occurrence, often considered a nuisance. But a National Oceanic and Atmospheric Administration report published Wednesday noted that the cases of tidal floods are increasing.
The study is the first to take into account all known oceanic and astronomical causes for floods, NASA said.
“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 in the statement.