Floods are already a well-known problem in many cities in the US and around the world.
The National Oceanic and Atmospheric Administration (NOAA) reported a total of more than 600 such floods in 2019. to begin a decade of dramatic increases in the number of floods, according to the first study that takes into account all known oceanic causes and astronomical for floods.
Led by members of NASA’s University of Hawaii Seascape Change Science Team, the new study shows that high tides will exceed known flood thresholds across the country more often. In the mid-2030s, in the US the coast will experience rapidly rising high tide floods, when a lunar cycle will amplify rising sea levels caused by climate change.
Moreover, floods will sometimes occur in groups lasting a month or longer, depending on the positions of the Moon, Earth and Sun. When the Moon and Earth line up specifically with each other and the Sun, the resulting gravity retreat and the corresponding ocean response can leave city dwellers facing floods every day or two.
“Low-lying areas near sea level are increasingly endangered and suffer due to rising flooding, and this will only get worse, ”Said NASA Administrator Bill Nelson. “The combination of the Moon’s gravitational pull, rising sea levels, and climate change will continue to exacerbate coastal flooding along our coastlines and around the world. NASA’s Sea Level Change Team is providing essential information so that we can plan, protect and prevent damage to the environment and the lives of people affected by floods. “.
“It is the accumulated effect over time that will have an impactSaid Phil Thompson, an assistant professor at the University of Hawaii and lead author of the new study, published this month in Nature Climate Change. Thompson pointed out that because high tide floods involve a small amount of water compared to hurricane storm waves, there is a tendency to view them as a less important problem overall. “But if it floods 10 or 15 times a month, a business cannot continue to operate with its underwater parking lot. People lose their jobs because they cannot go to work. Sewage pits become a matter of public health “.
Why will cities on such widely divided coasts begin to experience these higher levels of flooding almost simultaneously? The main reason is a regular oscillation in the Moon’s orbit that takes 18.6 years to complete. There is nothing new or dangerous about rocking; was first reported in 1728. What is new is how one of the effects of oscillation on the Moon’s gravitational pull – the main cause of the Earth’s tides – will be combined with rising sea levels resulting from planetary warming .
In the middle of the 18.6-year lunar cycle, the Earth’s regular daily tides are suppressed: High tides are lower than normal, and low tides are higher than normal. In the other half of the cycle, the tides amplify: The high currents become higher, and the low tides become lower. Global sea level rise pushes high tides in only one direction – above. So half of the 18.6-year lunar cycle counteracts the effect of sea level rise at high tides, and the other half enhances the effect.