Craig’s Linked List

Today I was reading this Slashdot story about this article on tapping geothermal energy for human consumption. Good stuff.

Of course any time there’s discussion about new energy sources, someone always brings up the unforeseen consequences argument. In this case: “wouldn’t we cool the earth’s core if we started using it’s energy, causing catastrophe?” This post says “no”:

I’ve seen too many comments about the “effect this would have on magma under the earth if we cool it this way.” The answer to these questions is that for a long long time, we’d have virtually no effect. The scale of human activity is just to small compared to the mass of the earth -the heat source for this power generation method. Go back to school and look at the graphics that show just how thin of an area the crust occupies on the earth. http://iga.igg.cnr.it/geo/what-is-for%20IGAnew_file/image038.jpg Now imagine for yourself just how thin of an area human activity would impact.

The poster misused “area” instead of “volume”, and he’s talking about energy impact rather than physical space, but this post did get me thinking… how much area do we actually take up? I mean us, personally, not our ecological footprint.

So I did the math:

• Start with 1 square metre per person. That’s roughly 3 feet to a side: a little crowded but you’re not pressed up against anyone.
• There’s roughly 6.6 billion people on the planet.
• 6.6 Gm² is 6,600 km²
• 6,600 km² is a bit larger than P.E.I., just about the size of Delaware, and a fair bit smaller than Puerto Rico
• If you divided Earth evenly, each person would get about 77,283 km²m²: 22,567 km² of land and 54,716 km² of water.
• That works out to a plot of land about the same size as Israel or New Jersey, and (mostly saltwater) lake nearly twice the size of Lake Superior an area the size of 14 U.S. football fields, or nearly 1.5 times the base area of the Great Pyramid of Giza.
• If you want to talk volume, each person could get a chunk of Earth 164 km³ big.
• If you limit that volume to 2 m high (the taller of you will have to duck), each piece would be 82,000 km² in area, which is a bit smaller than Austria.

I call dibs on the top-left corner.

Update:I made a big calculation mistake figuring the amount of area per person, which unfortunately lessens the entertainment value.