The topic of floods came to the fore in world news: hundreds of people died in Western Europe, for the first time in 50 years, settlements in Australia were flooded. It would seem that it could not be worse. But NASA scientists argue that in the near future, due to the moon’s orbit and climate change, floods will become much more frequent and destructive.
A NASA team at the University of Hawaii studying sea level changes has published their research in the journal Nature Climate Change.
The moon is known to cause the ebb and flow of oceans, seas and rivers on Earth. The satellite is not moving along a constant trajectory. Its orbit changes slightly every 18.6 years. This was first noticed back in 1728. Since then, the features of the course of such cycles and their consequences for the Earth have been established. “In the first half … of the cycle, daily tides on Earth are suppressed,” the scientists explain, “the maximum level of water rise (high water) is below the usual level, and the minimum level at low tide (low water) is higher than usual. In the second half of the cycle, the tides, on the contrary, intensify: the maximum level is higher than usual, and the minimum is lower. “
Humanity is already accustomed to these cycles. But now a new force is gaining momentum – global warming and rising sea levels.
This also affects the tides. As a result, scientists say, the maximum water level at high tide, which in the first half of the 18.6-year cycle should be lower than usual, turns out to be higher. In the second half of the cycle, when the tides are already strong, they will be even larger.
One of the study’s authors, Gary Mitchum, Associate Dean of the Institute of Oceanology at the University of South Florida, in an interview with The Washington Post, explained this phenomenon with a simple example.
You need to imagine a person sitting in a bathtub and clapping his hands on the water. The higher the water level in the bathtub, the more likely it is that the water will start to splash. As the level rises, the sloshing will be more intense.
“Small waves in the bath are the tide, and the volume of the water in the bath is the rise in the sea level. These two points are completely interconnected. But the combination of them means that you will certainly throw water out of the bath more often when the water level rises and the waves are greater, ”the scientist explained.
The Moon is now in the second phase of its 18.6-year cycle, meaning it is increasing tides. And researchers have already noted an increase in the frequency of floods.
By the mid-2030s, when the active phase of the cycle begins again, the sea level will be even higher due to climate change. Floods, scientists warn, will be even more frequent – three to four times – and even more powerful.
Moreover, these floods will not be less and less seasonal. It is not excluded, for example, the option of daily floods or several floods per week. Sometimes they will stretch for almost a month.
The negative consequences of these cataclysms will accumulate over time.
«It may also happen that floods will occur 10-15 times a month. Enterprises and companies simply will not be able to work if their parking lots go under water so many times.
And then it is no longer just an unpleasant situation. This is a serious economic blow to an individual, ”explains the study’s lead author, head of the University of Hawaii’s Sea Level Center, Phil Thompson.
People will lose their jobs because they will not be able to get to it. And the sewerage overflowing with water will create a problem for the health of the population, the scientist frightens.
The worst part of this will be the coastal areas. “The combination of the moon’s gravity, sea level rise and climate change will only exacerbate coastal flooding … around the world,” says NASA employee Bill Nelson.