How many steps were taken on the Earth Today?

From: James Coates
Sent: Friday, 31 May 2013 2:37 PM
To: Michael Kordahi; Andrew Coates (DPE AUSTRALIA); Chris Bright
Subject: RE: how many steps are taken on the planet today? #franklyspeaking

So 90.17 billion (trillion for our American friends).

I figure they do actually take a lot of steps, even if they don’t travel as far.

From: Chris Bright
Sent: Friday, 31 May 2013 2:29 PM
To: James Coates; Michael Kordahi; Andrew Coates (DPE AUSTRALIA)
Subject: RE: how many steps are taken on the planet today? #franklyspeaking

What about the 1 to 5 yr olds who don’t walk that much either.
Sorry couldn’t resist.:)
Sent from my Windows Phone


From: James Coates
Sent: ‎31/‎05/‎2013 2:23 PM
To: Michael Kordahi; Andrew Coates (DPE AUSTRALIA); Chris Bright
Subject: RE: how many steps are taken on the planet today? #franklyspeaking

Proportion of 1st-world population under 12 months: 1%

Proportion of 3rd-world population under 12 months: 2%

Remove those from the stepping population.

Also we’ll probably need to assume anyone over 65 isn’t taking a huge number of steps (let’s go with 30% of a younger person).

1st world over 65: 14%

3rd world over 65: 4.8%

Calculation is left as a trivial exercise for the reader.

From: Michael Kordahi
Sent: Thursday, 30 May 2013 3:27 PM
To: James Coates; Andrew Coates (DPE AUSTRALIA); Chris Bright
Subject: RE: how many steps are taken on the planet today? #franklyspeaking

Good effort.

But as Bright points out, babies don’t walk.

From: James Coates
Sent: Thursday, 30 May 2013 3:04 PM
To: Michael Kordahi; Andrew Coates (DPE AUSTRALIA)
Subject: RE: how many steps are taken on the planet today? #franklyspeaking

Simple, really (well, perhaps not SIMPLE but not desperately difficult if you allow for some approximations)

# people in the world: 6.91 x 10^9

Average number of steps taken per person per day?

This is not so simple…

Estimates for America are the only ones easily available online and they vary from 5000 (females) to 7000 (males)

Hmmm … that’s quite a significant difference (40% more!)

Let’s refine the numbers above.

World population (Female, 2010): 3.423 x 10^9 (49.6%)

World population (Male, 2010): 3.482 x 10^9 (50.4%)

Population growth rate: 1.19%/year

2013 estimates:

Female: 3.55 * 10^9

Male: 3.61 * 10^9

That still leaves us with the problem of the unmeasured masses out there.  Only 250M or so Americans and their lifestyle is anything but typical …

Ahh – I wonder if the Amish lifestyle is a good indicator of how much walking is required by 3rd world rural populations.

It probably is a lot closer than any other solid numbers we can find.

It turns out there has been a study of the Amish “steps per day” in the US – they came to 14000 (female) and 18000 (male) – slightly more than 2.5 times the urban US population.

3rd world urban populations would presumably walk less than their rural counterparts.

Let us take a few wild guesses now and split people into 3 groups:

1st world               F: 5,000spd, M: 7,000spd

Urban 3rd world F: 10,000spd, M: 13,000spd

Rural 3rd world   F: 14,000spd, M: 18,000spd

Now – how many people in each of those groups?

Take India as a sample for 3rd world rural vs urban population (72.73% vs (27.27%)

1st world: 1.16 x 10^9

3rd world urban: 1.34 * 10^9

3rd world rural: 4.36 * 10^9

Number of steps yesterday is approximately

(1.16 * ((5000 * 0.496)+(7000 * 0.504)) + 1.64 * ((10000 * 0.496) + (13000 * 0.504)) + 4.36 * ((14000 * 0.496) + (18000 * 0.504))) * 10^9 =

95.7 Billion (or 95.7 Trillion if you’re a silly American)

Cheers,

James