“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 explains.
“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,” the study claims.
The moon is not in a tide-amplifying cycle in 2021. So there is no danger of record-breaking flooding, right now.
But researchers are warning that the moon will return to its tide-amplifying cycle in the mid-2030s. That’s when worldwide sea levels rise for another 10 years.
What to expect
All coastal cities in the U.S. will see increasing high tide flooding in the 2030s thanks to a “wobble” in the moon’s orbit coupled with rising sea levels caused by climate change, according to the NASA report.
“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,” the space agency study predicts.
