A “wobble” in the Moon’s orbit is set to attribute in part to an onslaught ‘dramatic’ increase in floods expected to start in the mid-2030’s, according to scientists from the National Aeronautics and Space Administration (NASA).
The report, produced by the NASA Sea Level Change Team at the University of Hawaii and published in the Nature Climate Change journal, predicts a potential rapid increase in the frequency of flooding at high tide along coastal regions.
The study by NASA says that the lunar cycle combined with rising sea levels is set to drive major tidal flooding events.
The report cites the “wobble” of the Moon’s orbit as a contributing factor in potential disastrous flooding.
This wobble, which happens every 18.6 years, causes extremely high and low tides. For half of that time, regular tides on Earth are suppressed, meaning high tides are lower than normal and low tides are higher than normal.
NASA also details an increase in the global sea level as the other attributing factor to the floods which are predicted to sweep the earth in about 15 years’ time.
According to the study, the number of floods could quadruple as the gravitational effects of the lunar cycle combine with climate change to produce “a decade of dramatic increases” in water disasters.
Coastal cities would experience rapidly increasing high-tide floods lasting a month or longer.
“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,” says Bill Nelson, head of the space agency.
“What’s new is how one of the wobble’s effects on the moon’s gravitational pull – the main cause of Earth’s tides – will combine with rising sea levels resulting from the planet’s warming.”
The next ‘lunar assist’ to high tides will be around mid-2030, by which time global sea levels will have been rising for another decade.
“By that time it will have passed a “tipping point” and the result will be a leap in flood numbers on almost all US mainland coastlines.
“Low-lying areas near sea level are increasingly at risk and suffering due to increased flooding,” says Nelson.
“It will only get worse.”
According to the UN and numerous reports such as published in Nature Communications Journal, by 2050 coastal cities will see hundreds of millions of people at risk from floods made worse by rising seas..
Study co-author and NASA Sea Level Change Team Leader Ben Hamlington, said that urban planners should prepare for the increase in high-tide floods and extreme weather events and that flooding is more likely because the factors that are making it happen now will only be worse in the future.
According to NASA’s research, floods will occur in clusters lasting a month or longer, depending on the positions of the Moon, Earth, and the Sun.
NASA says that the study is the first to take into account all known oceanic and astronomical causes for floods.
Professor Mark Howden, Director of the Institute for Climate, Energy & Disaster Solutions at The Australian National University, further explains the lunar phenomenon responsible, known as the Moon’s “nodal cycle”.
“The orbit of the Moon apparently changes from the perspective of Earth,” Professor Howden says.
“Sometimes it’s tilted up one way and sometimes it’s tilted the other way.”
Professor Howden explains that during the amplified part of the cycle, “the Moon lines up with the Sun in terms of gravity” — with the combined effect increasing the height of high tides.
“Those cycles of the Moon have happened for probably billions of years, so they’re just part of the background world we inherit,” he said.
“The problem here is that we’re changing the sea level very quickly, so it’s going up at a record rate at the moment, and what used to be a relatively benign cyclical effect is now a ramping up effect.
“In Florida, they get what they call ‘sunny day flood events’ — it’s a day when there isn’t a storm pushing waves onto the shore, it’s simply that there’s a high tide.”
Scientists explain that although the Moon is currently in a tide-amplifying part of its cycle, the effects are not as environmentally significant as they will be next time around as sea levels continue to rise.