Questions for ‘Moon’s orbital wobble can add to sea-level rise and flooding’

people walk through a flooded street

Even in the absence of rain, tides can occasionally flood the streets of coastal cities, such as here in Miami, Fla. Soon, a tide-enhancing wobble in the moon’s orbit will kick in, making things far worse, a new study reveals.

Joe Raedle/Getty Images News

To accompany “Moon’s orbital wobble can add to sea-level rise and flooding


Before Reading:

1.  What are tides, how often do they occur and what causes them?

2.  Three major processes contribute to sea-level rise. Name as many of them as you can and explain how they contribute to changing ocean-surface levels.

During Reading:

1.  What is tidal flooding, based on the story?

2.  What is the moon’s so-called wobble? How does this wobble affect ocean levels?

3.  How long is the lunar-wobble cycle?

4.  When do the highest tides in the moon-wobble cycle occur? What celestial phenomena can occur at that time?

5.  How far can the moon’s orbital plane differ from the sun’s?

6.  How much can sea levels rise in St. Petersburg, Fla., during the lunar-wobble’s next cycle of sea-level rise, according to the story?

After Reading:

1.  Worldwide, a climate-related rise in sea level of about 3 millimeters has been occurring each year. That’s about an inch every eight years. Already that increase has been causing some problems to some areas, with major coastal erosion and cliffs, roads or buildings falling into the seas. How can the bonus rise in sea level due to the lunar wobble compare to the climate related sea-level rise? What type of acceleration of erosion or beach loss would you expect to see during the next wobble’s high point in sea level?

2.  Consider how communities might try to adapt to rising sea levels and tidal flooding. Describe three types of changes that communities might make. Which would likely be the most expensive change (and why)? Which would likely be the least expensive (and why)? Which would be easiest for a big city to make (and why)?