One of the scientific objections to Noah’s flood is that there is simply not enough water on the surface of the earth to cover all the mountains to the depths suggested by Genesis.
Google “noah’s flood not enough water” to read up on this objection.
Here’s a representative quote of such objections:
…there could not have been a worldwide flood as described in the Bible because there is simply not enough water in the earth’s atmospheric system to produce such a flood.
According to data from the U.S. Geological Survey, the amount of water in the earth’s atmosphere could not possibly cover the earth. In fact:
One estimate of the volume of water in the atmosphere at any one time is about 3,100 cubic miles (mi3) or 12,900 cubic kilometers (km3). That may sound like a lot, but it is only about 0.001 percent of the total Earth’s water volume of about 332,500,000 mi3 (1,385,000,000 km3)
If all of the water in the atmosphere rained down at once, it would only cover the ground to a depth of 2.5 centimeters, about 1 inch.
Additionally, because only 1.7% of the earth’s water is stored underground, there is not nearly enough water in groundwater storage beneath the earth’s surface to account for the amount of water necessary to flood the entire earth to the extent described in the Bible.
Simply put: there is not enough water in Earth’s atmosphere to raise the ocean’s levels over an inch, much less to cover Mt. Ararat with water from 40 days of rain. There is simply not that much water in the system.
Thus, in order to even entertain the possibility of a worldwide flood, one has to bypass all laws of physics, exit the realm of science, and enter into the realm of the miraculous, which many biblical literalists are willing to do. It is hypothetically possible that, say, the polar ice caps melted. This could raise the ocean levels beyond the 2.5 centimeters that all the earth’s atmospheric water could were it to all rain down, but even then the thaw would only slightly affect the world’s coastlines. Additionally, all scientific evidence points to larger polar ice caps in recent history, not smaller.
However research since 2000 has indicated that there may be a conservative estimate of between five to ten times more water inside the earth than there is in all the world’s lakes, rivers, and oceans combined.
I just found this interesting since up until now we have had no scientific evidence suggesting that the earth’s mantle is filled with great amounts of water, i.e. “the fountains of the deep.”
Also interesting is that this great amount of water is now found locked into mineral matrices from which it is very difficult to extract them. In other words, there is no known way that this water could spontaneously find its way back to the surface of the earth to flood it.
And God said, This is the sign of the covenant that I make between me and you and every living creature that is with you, for all future generations: I have set my bow in the cloud, and it shall be a sign of the covenant between me and the earth. When I bring clouds over the earth and the bow is seen in the clouds, I will remember my covenant that is between me and you and every living creature of all flesh. And the waters shall never again become a flood to destroy all flesh.