A new NASA study says coastal flooding is a far more urgent problem than previously thought. Cities along coasts should expect a “surge” of flooding as soon as the next decade, the study says.
The dramatic prediction pushes the previous deadline for disastrous coastal flooding forward by about 70 years.
The study, “Rapid increases and extreme months in projections of United States high-tide flooding” was published in the Nature Climate Change Journal. It was led by members of the NASA Sea Level Change Science Team. The study focused on U.S. coasts but was applicable to the whole world, NASA said.
According to NASA, the cause is a perfect storm of global warming and the effect of regular lunar cycles. Of particular note is a dynamic called “moon wobbling.”
“In the background, we have long term sea level rise associated with global warming. It’s causing sea level to increase everywhere,” Ben Hamlington, NASA team lead, told Reuters. “But when we look at the other factors causing sea level to change, we focused in on one in particular. So what we call ‘the nodal cycle,’ associated with basically the orientation, the relation of the moon relative to Earth. And what happens is that there’s this very long period signal, roughly 20 years, and this effect from the moon causes the tides to vary. So what we found is that this effect lines up with the underlying sea level rise, and that will cause flooding specifically in that time period from 2030 to 2040.”
The effect of the dynamic highlighted by Hamlington and his team applies to the entire planet save far northern coastlines like in Alaska. Such areas are rising due to unrelated geological processes, NASA says.
“This is eye-opening for a lot of people,” Hamlington said. “It’s really critical information for planners. And I think there’s a great amount of interest in trying to get this information from science and scientists into the hands of planners.”
So what can be done? For starters, city planners should plan accordingly in their construction projects, Hamlington said.
“A building or particular piece of infrastructure, you may want to be there for a very long amount of time, whereas something else you may just want to protect or have access to for a few years,” he said.
The NASA study echoes other dire predictions about coastal sea levels.
A study in the journal Nature Communications found that tropical nations in particular will be vulnerable to coastal inundation, in new research that more than doubled the number of people estimated to be impacted.
Using land elevation data gathered by laser pulses beamed by satellite to Earth, scientists identified coastal areas low enough to make them vulnerable to a one-meter rise in sea level – a level the world is on track to see by 2100. Higher water levels will likely lead to more damage and disruption from flooding and storm surges.
The team found that 62% of these low-lying areas were located in the tropics, with a third of the total in Asia.
(Production by: Dan Fastenberg)