Entrepreneurial Consultant - Programme, Change & Interim Manager, R&V (New Zealand's Premium Music Festival) - Management Consultant Accreditation

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## How much water do 9 Billion human bodies (@ 80% water) remove from the Earth's 'water system', and to what effect ? Is this significant ?

This idea is to do with Water. So, let's assume there is a finite amount of water on Earth, and it goes around the system from river to sea to rain etc. Now people are 80% water and we expect the Human population to become 9 Billion in the next 50 years, from 1 Billion 100 years ago (?). Now people & other large animals (eg those we eat) are in fact temporary reservoirs of water (i.e. the 80% body mass they take out of the Earth's water system for their lifetime). I'm wondering what effect this decrease of Water will have on the Earth / the environment / the weather ? Has anyone calculated the amount of water there is Vs the amount we're removing in this way ? I'd estimate an average weight of 50kg per person (to cover all ages & sizes). 80% of this is 40kg which is 40 litres of water I suppose. So then we multiply the population increase of 8 Billion in the last 150 yrs and we get 320 Billion litres of water temporarily out of the system - to what effect ?

## Closing Statement from Chris Goss

Hi Guys, (sorry for the late reply)

Thanks for your replies - I'm happy to learn that it's negligible !!

Two links you might find interesting. The first, a TED conversation from Hans Rosling pointing out the real problem is climate change, and the second is a TED presentation by Mark Brittman 'What's wrong with what we eat' ... how it affects climate change, and horrifically stating that 10 Billion animals (Cows, Pigs & Sheep only) are grown and slaughtered for food each year in the USA. This kind of blows my navel gazing out of the water (no pun intended), but thanks again !

1. http://www.ted.com/conversations/39/why_do_so_many_think_that_popu.html

2. http://www.ted.com/talks/mark_bittman_on_what_s_wrong_with_what_we_eat.html

• #### Alex Van Dijk

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May 20 2011: Negligible. An Olympic size pool would be 50m x 25m x 2.5m, which would give us a volume of 3125000dmcubed of water. This means that 8 billion people would fill 102400 olympic pools, which is a square of 320 pools length to length and side by side.

The actual size would be 16km by 8km with a depth of 2.5m. So all the water in all human bodies would fit in a medium sized, very shallow lake.

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• #### Barry Li

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May 20 2011: This question caused me to ask my self how much water does 9billion people hold? So as you said human are 80% water, and there's 9billion of them. Wow we have a lot of water with in us.