How many people can Loch Ness hold?

It's one of those "amazing" facts that is trotted out about Loch Ness. The fact that the volume of water in Loch Ness is equivalent to containing the entire population of the world. But by how much seems a matter of opinion.

This website suggests ten times the world's population. The Daily Mirror seems to say the same, but says "surface area" instead of volume. Bzzzzz! Meanwhile, looking further back, issue 235 of the Europe magazine from 1983 states it is three times the world population.

It is one of those factoids like the one that the Post Office Tower or Eiffel Tower could be submerged in the loch without trace. But when this population fact was first mentioned was a bit of a mystery to me, though I certainly recall it going back before the Internet. I checked most of the classic books, but couldn't find any mention of it. Where had it come from and indeed does it stack up?

Now the volume of water in Loch Ness is stated as 7.5 cubic kilometres in its Wikipedia entry. This translates to 7.4 billion cubic metres. What is the average volume of a human? Not so easy to figure out, but good old Google suggested that water displacement measurements of 521 people of varying ages gave 66.4 litres or 0.0664 cubic metres. That seemed to be about half what I thought for an adult, but we are including babies and kids in our experimental mega-plunge.

Divide the volume of the loch by this average human volume and you get about 111,445,783,130 people fitting into Loch Ness. Since the world's population is currently estimated at about 7.3 billion, then you'll get them all into Loch Ness not just 10 times over but more than 15 times over. It seems our factmeisters were right but also underestimating things.

But what about surface area as the Daily Mirror misquoted? The best known fact on this wise is that the Isle of Wight can hold the entire standing population of the world. Okay, what about Loch Ness with a surface area of 56 million square metres? If we assume five people squeezing up per square metre, then that's 280 million people, which is well off the mark.

But, again, who first concocted this fact? Was it the Loch Ness Investigation Bureau or some more obscure book or booklet? If anyone knows, leave a comment or send an email.

The author can be contacted at lochnesskelpie@gmail.com