The result is based on ocean tidal data collected from 89 coastal areas covering all states and territories in the United States except Alaska. These data were examined along with flood records and forecasts of future sea level rise up to 2080.
Research results have shown that the combined effects of sea level rise linked to climate change and natural changes in ocean tides will lead to increased coastal flooding.
The prediction was recently reported in a study in Nature Climate Change. The study was conducted by members of the Sea Level Change Team of the US space agency NASA. The study’s principal investigator was Phil Thompson, a member of the Sea Level Change Team and director of the Sea Level Center at the University of Hawaii.
Thompson said in a statement he expects the largest increases to occur along the U.S. Pacific and Gulf of Mexico coasts, which include Hawaii and other Pacific islands. This is important because this is where high tide flooding goes from being primarily “a local or regional problem and becoming a national problem affecting the majority of the coasts of our country,” he said.
The researchers note that many U.S. coastal areas, especially along the Atlantic coast, are already experiencing such flooding. High tide flooding occurs when the tides reach between 0.5 meters and 0.6 meters above the daily average high tide, according to the National Oceanic and Atmospheric Administration (NOAA).
NOAA has reported more than 600 incidents of this type of flooding – also known as “sunny day” flooding – in 2019. Such activity is expected to worsen and lead to longer duration flooding as time goes on. that high tides rise in the future and that the sea level continues to rise. .
Ben Hamlington was a co-author of the study. He is part of NASA’s Jet Propulsion Laboratory in California and also leads the Sea Level Change team. He said in a statement that the findings can be an important resource for U.S. coastal planners who could focus more on preparing for extreme events rather than flooding at high tide. For planning purposes, “it’s important to know when we’re going to see an increase,” Hamlington said.
Thompson agrees that the study results can be used by scientists, engineers and government officials who are accustomed to preparing for rare and severe weather events such as a 100-year storm. “But we are showing that it is important to plan for months or extreme seasons during which the number of floods episodes, rather than the magnitude, is exceptional, ”he said.
How the moon changes the tides
The prediction of an increase in high tides from the mid-2030s is linked to a normal lunar cycle. NASA says the cycle – which affects how the Earth aligns with the moon and the sun – alters our planet’s gravitational pull. This, in turn, affects ocean tides.
The cycle causes “a regular oscillation in the orbit of the moon which takes 18.6 years to complete, ”says NASA. In the middle of the moon’s cycle, high tides on Earth are below normal and low tides are higher than normal. In the other half of the cycle, high tides increase and low tides decrease.
Currently, NASA says the moon is in the cycle that intensifies high tides. And although there have been problems with flooding at high tide, there has not been enough sea level rise for high tides to “steadily increase” flood levels, said. Researchers.
But the next time the cycle recurs, in the mid-1930s, sea level rise “will have been at work” in those years, NASA noted. The higher seas, combined with the new lunar cycle, “will cause a jump in number of floods on almost all of the continental United States, Hawaii and Guam. ”
Such flooding could leave people in cities experiencing flooding “every day or two,” the research team predicts.
I am Bryan Lynn.
Bryan Lynn wrote this story for VOA Learning English, based on reports from NASA and the University of Hawaii. Susan Shand was the editor.
We want to hear from you. Write to us in the Comments section, and visit our Facebook page.
Words in this story
tide – m. the steady rise and fall of sea level
episode – m. a single event or period of time
magnitude – m. the large size of the importance of something
ordinary – adj. something that happens often
oscillate – v. move from side to side
jump – m. a sudden increase or improvement