Skipping rocks is a uniquely human activity. There is no evidence any other animal engages in such an activity, though, admittedly, I have not done research into whether or not other they do. However, it seems to be the case, at least intuitively. We may even consider skipping rocks, alongside with language, society, and all the stuff anthropologists are on about, to be one of the hallmarks of humanity, a great accomplishment of all humankind.

The proliferation of this activity has skyrocketed with the advent of the industrial revolution and our current information era, providing the average person with more free time to skip rocks and platforms, such as YouTube, to share our rock-skipping success. As with any other activity in the Anthropocene, moderation does not seem to be at the forefront of our minds and, as with consuming single-use plastics, releasing excess carbon emissions, and polluting our waters, we take this activity of skipping rocks to its extremes, disregarding its harmful effects on our planet today and in the future. Many will disagree with the comparison to these assaults on our planet’s health, but should we not consider the impact of skipping rocks on our environment, it may destroy our planet and rob our children of the future they deserve.

Determining whether or not we are skipping too many rocks requires us to first understand the impact that skipping rocks may have on our planet and its environment. One of the the most pressing ecological problems facing the human species is climate change leading to rising sea levels, among many other consequences. Any child understands the effect that adding things to water has on its volume and since the time of Archimedes, we have understood and been able to quantify the principle of displacement. It would be naive to discount the contribution of rocks skipped into ponds, lakes, and oceans toward the rise in sea levels.

To quantify these potentially disastrous effects on the global scale we must first understand how many rocks are skipped across the world. This data does not seem to be publicly available but extensive research into the topic reveals a ballpark estimate. Around 1.2 trillion stones are skipped every year. The exact methods used to determine this value are outside the scope of article.

Many scientists attribute changes in climate and the rising sea levels to the emission of greenhouse glasses but they fail to take into account the effect that rock skipping may have on this phenomenon. The dimensions of a good skipping stone, according to 13 Tips to Becoming a Better Stone Skipper by U.P. Supply Co., are 3-5 inches in diameter and a thickness of half the width of a finger holding a stone (which works out to be 3/8 of an inch, if my fingers are comparable to those of the stone skipper’s). This works out to 77.18 milliliters of volume for each rock, leading the total volume of rocks thrown into our planet’s waters to be 92.6 billion liters annually.

According to Gabriel Jack on Quora, 6.19 exaliters of water are needed to raise the sea level by 1 inch, so our stone skipping habits will raise the oceans by 1.50×10^-8 inches yearly. Surprisingly, the overall effect seems to be negligible, at least intuitively.

This is not the only concern. Humans may skip rocks faster than new rocks can be created or reemerge from their watery graves. This may lead to future generations unable to enjoy this quintessentially human pastime. We must also consider if the rate at which we are skipping stones is sustainable and whether or not are are stealing necessities from the future for the whims of today.

After nearly five minutes of discussion with my roommate who has an extensive education in the earth sciences, we have determined that it would be a fool’s errand to quantitatively determine the amount of new stones suitable for skipping that are created in a year.

However, by using an ancient method employed by Greek philosophers, guesstimating, we can accomplish this task. New stones suitable for skipping are created as larger geological bodies erode and give way to small rocks. This happens continuously, but while I have witnessed with my own eyes many people skipping stones, I have never witnessed the creation of a new skipping stone through erosion or any other method. Extrapolating my own personal experience out to the whole of planet earth, unless rocks slow their erosion when humans are nearby (an extremely unlikely scenario), it is clear that humans use up rocks quicker than nature can replenish them.

This leaves no doubt that, while skipping stones does not contribute to the problem of rising sea levels (so I guess we’ll have to, like, reduce our carbon emissions or something) it is not a renewable activity. Unequivocally, our guesstimation concludes that we are skipping too many rocks and are threatening the right of future generations to do the same. Do we believe that our leisurely activities today are more important than those of our children? It is imperative that, as with all things, we skip stones in moderation.