How much of the Earths mass is made up of Humans? It's quite an interesting question, so I'm going to do some rough estimations to figure out what
percentage of the Earths mass is made up of Humans. Next I'll take it even further and do some extrapolation to see how much of the Earths mass could
be "converted into Humans" and how fast it could happen. As our population increases the material for creating all those Human bodies can only come
from one place: Earth. The calculations required to do these estimations are remarkably simple so I hope you can spend a few minutes with me to see
what the result is. I don't even know the answer yet.
First we need to work out what the average body mass of a human is. This is probably the most difficult part. The Wikipedia page for body weight[1]
informs us that the average weight of a person can vary quite a bit throughout the world. If we get the average weight of the 4 countries listed by
Wikipedia, the result is about 80kg. However, one must keep in mind that a large percentage of the world are living in poverty and are often very
malnourished and underweight. Other sources claim the average weight of a modern Human is about 70kg[2][3]. I will go with the more conservative
number of 70kg for my estimations.
To get the mass of all Humans on Earth we need to know how many humans are presently on Earth. As of September 26, 2011, 14:38 EDT, the total world
population is at 6,992,664,111[5]. That is almost 7 billion people. Estimations report that by October 31 of this year we will reach 7 billion
people[6]. Lets use that clean number for these estimations. If we multiply 7 billion by 70 we will get the total mass of all Humans on Earth in
kilograms. The answer is 4.9x10^11 or in simpler terms: 490 billion kilograms. Keep in mind that there is probably a small range of error with that
estimation.
Next we need to know the mass of the Earth. For all intents and purposes Humans and everything on the Earth can be considered a part of the Earth's
total mass. Once again the numbers aren't exact, Google says the mass of Earth is 5.9742x10^24 kilograms but other sources have a very slightly
different number[7][8]. To account for this deviation I have rounded the number down to the closest value which all parties seem to agree on. Now we
can move onto the calculations we've all be waiting for. By using the total mass of all Humans and the mass of the Earth we can easily work out what
percentage of the Earth is made up of Humans.
Mass of all Humans: 4.9x10^11 kg
Mass of Earth: 5.97x10^24 kg
The equation for calculating a percentage[9] is simple:
(Given amount / Total amount) x 100
thus
(4.9x10^11 / 5.97x10^24) x 100
= 0.0000000000082
Ok...well it's fascinating but that's nothing amazing, it's an extremely small percentage. But lets take a little look into the future. It took us
over 100 years to go from a population of 1 billion to a population of 2 billion (1804-1927), but we've gone from 2 billion to 7 billion in under 100
years[10]. As of 2009 the estimated growth rate of the Human population was a 1.1% increase annually[11]. Sounds like a small rate of growth right?
Wrong. If that rate of growth were to remain steady it would only take another 250 years before we had over 100 billion people on the planet. In 500
years there would be over one and half
trillion people on Earth. Once we get past 900 years we would quickly reach 150 trillion people.
Obviously we wont get that far because there is only about 150 trillion square meters of dry land on Earth[12]. Also remember that as the population
grows so does our demand for not only land, but also energy, food and other natural resources. So lets just do some fun calculations to see how much
mass we could theoretically extract from the Earth in order to create trillions of Humans. We'll start by using the estimated population in 250 years
if we keep growing at 1.1% each year and then look at 500 years and finally 900 years into the future.
100 billion humans have a total mass of: 7.0x10^12 kg (7 trillion kg)
1.5 trillion humans have a total mass of: 1.05x10^14 kg (105 trillion kg)
150 trillion humans have a total mass of: 1.05x10^16 kg (10.5 Quadrillion kg)
thus
250 years:
(7.0x10^12 / 5.97x10^24) x 100
= 0.000000000117
500 years:
(1.05x10^14 / 5.97x10^24) x 100
= 0.00000000176
910 years:
(1.05x10^16 / 5.97x10^24) x 100
= 0.000000176
You can see that if the population were to keep growing at a rate of even 1.1% each year Humans will start to accumulate quite a large mass. The
percentages still aren't as dramatic as I was hoping for, our total mass didn't even reach 1% in any of these estimations. However, it's easy to see
that we cannot sustain this rate of growth forever. Like it or not we will have to eventually reach a state where we have a 0% growth rate otherwise
we are doomed to fail. Similar estimations have probably been done but I was bored and needed something to do. Hope it was at least slightly
interesting.
REFERENCES:
1.
secure.wikimedia.org...
2.
wiki.answers.com...
3.
wiki.answers.com...
4.
www.physlink.com...
5.
www.worldometers.info...
6.
www.reuters.com...
7.
www.google.com.au...
8.
www.universetoday.com...
9.
mathematics.blurtit.com...
10.
secure.wikimedia.org...
11.
secure.wikimedia.org...
12.
hypertextbook.com...
13.
www.google.com.au...
14.
www.census.gov...
edit on 25-9-2011 by ChaoticOrder because: (no reason given)