Led by members of the NASA Sea Level Change Team at the University of Hawaii, the study found that high tide flooding could occur more frequently on several coasts of the United States.

High tide flooding, often referred to as coastal flooding, is already occurring regularly in many coastal communities as water regularly flows into roads, backyards, and commercial areas.

In fact, two factors could combine to make flooding worse at high tide, the study said: an increase in sea level due to climate change - and the moon.

The moon's orbit is due to its regular "sinking". It's completely natural, NASA says, and it was recorded until 1728.

Half of the Moon's 18.6-year cycle produces low high tides and high low tides; The other causes high tides and even low tides.

But NASA says global sea level rise is likely to push that high tide even further.