How does the moon ‘wobble’ affect rising tides?

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Source: Indian Express 


Scientists are estimating that moon wobble would bring high tides in some coastlines of the world in the next decade. This may cause severe flooding, threaten coastal communities and lead to submergence of the coastal landscape.

  • The phenomenon of moon wobble is expected to enhance flooding on Earth in the middle of the next decade. 
  • The assumption is based on a study published in the journal Nature Climate Change.

About the study:

  • It aims to untangle all of those variables that are needed for improving predictions about the future of floods.
  • It found that our oceans are rising because of climate change. They’re getting awfully close to the brim in coastal communities due to decades of sea-level rise caused by rising temperatures.
  • It warned that the moon wobble would heighten high tides in the middle of the 2030s, but it also showed that this prediction does not apply uniformly to every coastline everywhere.
About Moon wobble:
  • It is a regular oscillation that humans have known about for centuries.
  • It is one of many factors that can either exacerbate rising sea levels or counteract them, alongside other variables like weather and geography.
Why does the moon wobble?
  • The moon revolves around the Earth about once a month, and that orbit is a little tilted. To be more precise, the moon’s orbital plane around the Earth is at an approximate 5-degree incline to the Earth’s orbital plane around the sun.
  • Because of that, the path of the moon’s orbit seems to fluctuate over time, completing a full cycle — sometimes referred to as a nodal cycle — every 18.6 years.
Effect of moon wobble:
  • High tides on this planet are caused mostly by the pull of the moon’s gravity on a spinning Earth. On most beaches, you would see two high tides every 24 hours.
  • At certain points along the cycle, the moon’s gravitational pull comes from such an angle that one of the day’s two high tides is a little higher, at the expense of the other.
  • During its most rapid upward phase, it acts to enhance the effective sea level, and during its most rapid downward phase, like we’re in now, it acts to suppress the effective sea level.
  • As per the study, the wobble could cause high tide levels at a beach to oscillate by 1 or 2 inches over the course of its long cycle, thereby raising the baseline.
    • The more your baseline is raised, the smaller the weather event you need to cause a flooding event.
Way Ahead:
  • High-tide flooding related to climate change is expected to break records with increasing frequency over the next decade. 
  • It’s important to prepare for the mid-2030s, as it is the point where the switch flips and the natural cycle of the moon starts to amplify the rate of sea-level rise.
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