# Offbeat Math: Sizing Up A World Of 7 Billion People

First Posted: 10/28/11 09:01 AM ET Updated: 10/29/11 12:26 PM ET

The UN's forecasters have estimated that Oct. 31 is the day world's population passes the 7 billion mark. Seven-thousand-million is a staggering number, and CBC News had some fun compiling this list to help put the idea of that many people into perspective.

What's your place in a world of 7 billion? Take the BBC's quiz to find out where you rank

(Please note, when dealing with a crowd of 7 billion people of varying age, sex, height, appetite, fitness level, and shoe size, the endeavour is far from an exact science. These calculations are based on best estimates and averages.)

## Take a deep breath

We all need air, but how much of it do 7 billion people consume?

People breathe at different rates, depending on their age, sex, fitness level and what they're doing at the time. In broad strokes, though, the average person breathes about8 litres of air every minute while at rest, or about 11,520 litres a day.

So the world's population inhales at least 80,640,000,000,000 (80.6 trillion) litresof air a day, and converts more than 3,850,000,000,000 (3.85 trillion) litresof oxygen to carbon dioxide.

A University of California study determined that the average person breathes about 52 litres a minute when running, so if the entire world went jogging together for an hour we'd breathe about 21,840,000,000,000 (21.8 trillion) litres of air.

One hectare of average forest creates about enough oxygen to support 19 people, according to the U.S. Forest Service. Using that as the benchmark, the world's population needs at least 368,421,052 hectares of forested land to provide us with the air we need â€“ an area roughly 650 times the size of PEI and 5 times the size of Manitoba.

## Food, water and gas

Part of humanity over-eats, others don't get nearly enough food. But the average human ideally needs around 2,200 calories a day, or 15,400,000,000,000 (15.4 trillion) calories for the human population.

If you wanted to "supersize" the world, the necessary calorie count works out to about 28,518,518,519 McDonald's Big Macs a day.

No matter what people may claim, everyone is a little gassy (particularly after eating things like fast food). According to the U.S. Department of Health and Human Services, the average person passes gas anywhere from 14 to 23 times a day, producing a daily average of about a litre of flatulence (made up of carbon dioxide, oxygen, nitrogen, hydrogen, and methane). Humanity's dailycloud of 7 billion litres of gas is enough to fill Toronto's Rogers Centre (formerly known as the SkyDome) about four and a half times. Try blaming that on the dog.

The average person should drink about 2.5 litres of water a day, according to studies by the U.S. Institute of Medicine. If everyone got the drinking water they needed, the world's population would consume about 17.5 billion litres a day, or the equivalent of about 7,000 Olympic-sized swimming pools. It would take the proposed Keystone XL pipeline expansion in Western Canada, which is designed to carry around 500,000 barrels of oil a day, about 220 days to transport that much water.

Given that the average person passes about 2 litres of urine a day, the world would subsequently relieve itself of about 5,110,000,000,000 (5.1 trillion) litres a year. That's equivalent to the amount of water that flows over Niagara Falls in about two and a half hours when the falls are at their peak.

## Being social

It takes about one second to say "hello" to someone. Assuming you wanted to greet the world's entire population of 7 billion one at a time, it would take you roughly 222 years of working the crowd non-stop.

A gigabyte works out to the equivalent of about 100,000 short emails. An entry-level home internet plan from Bell includes 2 gigabytes of internet use a month plus a \$2.50-per-gigabyte charge for any extra bandwidth used. If you wanted to e-mail a "hello" to everyone on Earth individually from that basic internet account, it would cost you \$26.95 for the monthly internet plan, plus about \$174,995 for the extra bandwidth you'd need. (Of course, you could save some cash by opting for one of Bell's bigger-bandwidth packages.)

According to the Forbes list of the world's billionaires for 2011, the world's richest man was Carlos Slim Helu from Mexico, with a net worth estimated at \$74 billion US. He could afford to treat every person on Earth to lunch at Tim Horton's â€“ a sandwich and extra-large coffee, plus a box of 20 Timbits to take home for later.

If the U.S. military budget for 2011 was shared out to the world's population, each person would get roughly \$100. Based on average annual income, that's about two months' salary for people in places such as Malawi and Somalia, according to the International Monetary Fund, or a bit less than the average North American spends in a day.

A really, really big show:

If you gathered everyone on Earth to watch a concert and packed 'em in at one person per 4.5 square feet â€”a dense crowd, based on the basic crowd-calculation rule worked out by University of California professor Herbert Jacobs â€” the general-admission audience would cover about 2,926.5 square kilometres. That's about 51.7% of the land area of PEI. (Of note, one of the biggest PEI concerts of the year was Elton John's two-night appearance at Credit Union Place in Summerside â€” 5,400 tickets were sold per show.)

If you flew everyone in for the concert, it would take 28 million flights using Boeing's new 787-8 Dreamliner.

If they all flew to the mainland and came over the Confederation Bridge in Toyota Corollas, the best selling car in the world, at 4 people per car the line of bumper-to-bumper traffic would stretch roughly 9.6 million kilometers, or go around the earth at the equator more than 240 times. (And it would be very difficult to find your car after the show.)

## Human chain

If everyone on Earth joined hands to form a human chain, it would stretch about 7 million kilometres. The chain would circle the Earth at the equator about 175 times, stretch to the moon and back about nine times, and reach about one-fifth of the way to Mars when it's at its closest point to Earth.

And that chain is growing. At a global birth rate of 19.15 per 1,000 population, about 4.4 babies are born every second.

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12:10 PM on 10/30/2011
This never ending world population growth is not sustainable.

We have a food crisis, a water crisis, an oil crisis, a climate change crisis, a financial crisis, an immigration crisis and a jobs crisis. All these problems are made harder to solve with an ever growing world population.
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Rob Vann
Hope for the best,Plan for the worst,Take what cms
08:52 PM on 10/29/2011
I love this article....so many numbers it boggles the mind. Great trivia but it misses the point completely.

Some simple math and a reality check:

OverseasVet
stuck in a 3rd world country called texas
03:07 AM on 10/30/2011
Thanks for the link. I now have no hope for my children. This should be sent to washington right away. The GOP has clearly chosen to ignore it and surprisingly so have the democrats. It is clear that nature will have to decide from the list on the right hand side. The deficit debate is clearly just a distraction from a much larger problem.
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Rob Vann
Hope for the best,Plan for the worst,Take what cms
10:24 AM on 10/30/2011
Glad you took the opportunity to check this out. Albert Bartlett has testified before Congress quite some time ago but of course was ignored. because the solutions go directly against the neoliberal policies of the GOP and dems . "We as a country" has changed to "We as a world" need to consume more resources to drive our economies. More and more people chasing declining resources.

The media.. isn't helpful. Articles like this trivialize the real issues and at a time when out footprint turns seven billion...well lets just say a wardrobe malfunction on Dancing With The Stars gets more serious attention.

I watched the deficit debate and as the CEO of Starbucks correctly pointed out the ..Government is broken..it is no longer functional. We need a new paradigm that address the real issues facing humanity. What we have no longer works.
02:10 PM on 10/29/2011
7 Billion people, a nice number. Now STOP listening to the fear mongers who would have you
to belive that this is a problem.

The entire 7 Billion people can fit into Austrailia with one acre for each person and there would still be the rest of the world Vacant

Most of the problems that the world faces are created by Man himself. Greed , Intolerance , War,
Hunger and Fear are spread by those who want to have Supreme Control over evryone and everything on this Planet.

Now if you are truly concerned , DO YOUR HOMEWORK and search for the TRUTH !
TonyOnly
Truth matters.
05:07 PM on 10/29/2011
"The entire 7 Billion people can fit into Austrailia with one acre for each person and there would still be the rest of the world Vacant"

That's a ridiculous argument. If you really believe as long as we can do that the planet will still be able to support us, you need to take some of your own homework advice. Global population is currently doubling every 50yrs. That means by the end of this century the population of the planet will be around 28 billion.. You don't think the problems you mentioned will be much worse when there's 4 times as many people as there are now?
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Rob Vann
Hope for the best,Plan for the worst,Take what cms
08:55 PM on 10/29/2011
Here is an assignment for you:

Please hand it in on time...I check homework.
SkeeBee
Offending InFoxtrination Sufferers With Facts.
01:02 PM on 10/29/2011
That stat: What the US spends on Military equaling \$100 for each of us all, reminds me of a bumper sticker I have:
"Wouldn't it be great if schools had all the money they need and the army had to have bake sales to buy bombers?"
Yup.
It would.
Troll magnet activated.......
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Rob Vann
Hope for the best,Plan for the worst,Take what cms
09:27 PM on 10/29/2011
Not sure how this matches up with the hundred dollars you refer to.. but somewhere I read that is costs each of us 1 million dollars (\$1,000,000) to keep one soldier on the ground in Afghanistan for one year. You are so right... Education before Militarization.

The US .. well only \$850,000 per soldier.. greater efficiency in mass production??
SkeeBee
Offending InFoxtrination Sufferers With Facts.
03:36 AM on 10/30/2011
\$100 for every soul on Earth
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Rob Vann
Hope for the best,Plan for the worst,Take what cms
09:30 PM on 10/29/2011
Getting late.. I should have said .. it costs ALL of us 1 million...
12:06 PM on 10/29/2011
We are all in this together, and together is the only way we can all live in peace 7B only gives us more strength to become the people the universe expects us to be.
02:26 PM on 10/29/2011
The universe expects as much of us as it does of the bacteria living in your digestive tract or the deer living in the bush. It's too bad we have convinced ourselves that we are somehow special, usually because a god has made us special, and we therefore have the right or even obligation to subdue and rule over all other life. We are not the first dominant species to populate the earth, nor will we be the last. We could do a lot better and last a lot longer if we accepted that and were able to use the brain evolution provided us with to rationally plan for our existence in this maze of life.
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gx5000
Life's too short, be happy..
01:17 AM on 10/30/2011
Unfortunately, the Human animal cares little for anything else but its own survival...
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kenl77
10:15 AM on 10/29/2011
Can 7 billion people be wrong?

The answer of course is yes. It is manifestly wrong that the earth is now burdened with 7 billion people. The earth needs clean air and water, trees and bears. It certainly does not need even one more human being.
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SidelineBoy
03:02 PM on 10/29/2011
If your answer makes sense to you, great! But your argument for bears is caught me off guard.
03:15 PM on 10/29/2011
I don't know that it is right or wrong, but it is not likely sustainable. One thing we can see from natural history is that the world does not need us or bears or trees or even 'clean' air. The earth spins on regardless of our existence and life seems to carry on despite the considerable barriers nature occasionally throws up. Our particular species does need a lot of things that we have taken for granted and we ignore them at our peril. With 4 or 5 mass extinctions already evident in earth's history, it is almost inconceivable that there won't be more. Hopefully, we won't be the cause of our own, but that looks a bit unlikely.
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09:06 AM on 10/29/2011
Ooops! That number shouldn't have been 300,000 it should have been artificially supporting 300,000,000. My bad.
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09:05 AM on 10/29/2011
America's natural resources are actually meant to support only about 250,000 people yet it is supporting over 300,000 thus there is stress on its resources. Imagine how much stress there is on the whole planet. How big is seven billion? Too big! It is time to bring back chasity belts for men as well as women.
TonyOnly
Truth matters.
08:30 AM on 10/29/2011
Over population is not something to treat lightly.

50yrs ago global population was 3.5 billion . 50yrs from now the population may have doubled again. At that growth rate, by the end of this century we could be approaching 30 billion people.

Some say population will continue to grow by the same 4 billionish it did over the last 50yrs. But I doubt that's accurate. More people means more reproduction and therefore a faster rate of population growth.

But whether it's 15 or 30 billion by the year 2100, it's destined to become a very serious problem. Everybody's going to want a piece of the pie. Will the pie be big enough?

Fresh water is already a problem. What do you think it's going to be like with that many people? Where are they all going to work? Do you think employment growth will match that kind of population growth? Unlikely. The environment is an issue now. Can you imagine the waste generated by 30 billion people?

These are just a few of the things that may overwhelm us by the end of this century. At this point we're not even willing to consider over population an issue. But if we continue to grow at this rate, it's destined to become the #1 issue for humanity. We need to consider it before it's to late.
Felix99
Born to be mild!!!!
02:27 PM on 10/29/2011
Youi're right, Tony, our population is nothing to treat lightly and yet we continue to do it!!!

On CBC's Quirks & Quarks today, a couple of population experts said that we have REAL problems!!!! We're pretty well fished out, the land we use is in overdrive, the amount of land available for agriculture is decreasing, and the water from glaciers is running out. They felt that a sustainable population would be about 2 billion people!!!! Scary!!!

Their first comment when asked about the significance of a population of 7 billion people was: "Be afraid, very afraid"!!!!!!
HUFFPOST SUPER USER
Good to know
04:49 AM on 10/29/2011
We are the 'Borg'....
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Balkingpoints
World Citizen Forum / writer's open mic - any topi
03:35 AM on 10/29/2011
I have been in line at Wal-Mart with all 7 billion in front of me... ;^)

- Balkingpoints / www
02:12 AM on 10/29/2011
bring on the Tim Horton's.

who came up with these stats and comparisons?

where was the Getty picture taken?
schrodster
veni vidi I'm outta here
12:54 AM on 10/29/2011
7 Billion. I'm a bigger minority than I thought.
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Louis Bernardi
I live in a treehouse!
12:44 AM on 10/29/2011
"These things have a way of working out, I'm sure half of Asia will die tomorrow, we'll be fine." -Stephen Harper
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gx5000
Life's too short, be happy..
01:20 AM on 10/30/2011
I lol'ed, should I feel guilty now ?

It's true what the right thinks, we're not very patriotic, we're just not dying fast enough.
To the MacDonalds !!!!
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Whistlejackett
Hey stop doing that
03:34 PM on 10/28/2011
This is not a milestone, it is a disaster. A global disaster.
This user has chosen to opt out of the Badges program
02:27 AM on 10/29/2011
I completely agree.
09:06 AM on 10/29/2011
a man made disaster

we are the earths disaster

now i shall go out and CONSUME