Upcoming natural changes in the Moon’s orbit – a so-called Moon “wobble” – coupled with rising sea levels caused by climate change could lead to record flooding on the Earth in the coming years, a recent study by the United States space agency NASA and the University of Hawaii has found.
The record flooding is projected to begin in the 2030s and last 10 years, according to the study, which focused on the phenomena’s effect in the US.
There were 600 floods from high tides in the US in 2019, according to the National Oceanic and Atmospheric Administration. That number is expected to increase by several times into the 2030s, according to the study, which was published in the Nature Climate magazine. The flooding is projected to occur in clusters that could last for a month or longer.
While the high tide flooding in question involves less water and is often considered less damaging than floods caused by hurricane surges, “it’s the accumulated effect over time that will have an impact”, Phil Thompson, an assistant professor at the University of Hawaii and lead author of the study, said in a statement.
“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,” he said. “Seeping cesspools become a public health issue.”
The so-called Moon “wobble” is not a new phenomenon. It was first reported in 1728 and is part of an 18.6-year natural cycle. During the first half of the cycle, the Earth’s regular tides are suppressed. During the second half, the tides are amplified, according to NASA.
The Moon is currently in the amplification half of its cycle, already causing increased flooding along many coasts, a result of high sea levels caused by climate change, according to NASA.
Another decade of rising sea levels will have severe consequences when the Moon is again in the amplification half of its cycle, the researchers found, resulting in a surge in flooding on all US mainland coastlines, Hawaii and Guam and sparing only far north coastlines like Alaska.
Researchers studied 89 tide gauge locations in coastal regions across US states and territories, astronomical cycles and the likelihood of tide-affecting phenomena to make the projections, which stretch to 2080.
NASA Administrator Bill Nelson, in a statement, said the research is crucial to allow coastal areas to prepare for the more flooded future.
“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,” he said.
“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.”