# If Everyone on Earth Sat in the Ocean at Once, How Much Would the Sea Level Rise?

Posted March 31st, 2021

### Putting Ourselves in Our Place: What If We All Sat in the Ocean at Once?

Editor’s Note:  Probably this is something you’ve wondered about. If everyone on earth decided to go swimming in the ocean at the same time, would there be room for all of us? And would the water spill out of the world’s oceans causing devastating flooding?  To put our minds at ease, here’s the answer from the Curious Kids section of at The Conversation website.

You can think about the oceans as a gigantic bathtub. More than 70% of the Earth’s surface is ocean, giving this bathtub an area of about 140 million square miles. To figure out how much the water will rise, we need to know the volume of people sitting in it and divide it by this ocean area.

Currently, there are almost 8 billion people on Earth. Human beings come in all sizes, from tiny babies to large adults. Let’s assume the average size is 5 feet tall – a bit bigger than a child – with an average volume of 10 cubic feet. Only half of each person’s body would be submerged when they sit down, so only 5 cubic feet adds to the water level. With 8 billion people total, you can calculate 5 x 8 billion which gives a whopping 40 billion cubic feet that would be added to the oceans.

But remember, this volume would be spread over the vast area of the oceans. Using the same bathtub math as before, we divide the 40 billion cubic feet of volume over the 140 million square miles of ocean.

The answer? The total rise in sea level would be about 0.00012 of an inch, or less than 1/1000th of an inch. If everyone completely submerged themselves, this would double the answer to 0.00024 inches, which is still only about the width of a human hair.

It turns out the oceans are enormous – and humans are just a drop in the bucket.

Source: The Conversation.

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