It's only alarming if you believe that the human population is close to the carrying capacity of the Earth. Given that the densest population centers are also the richest, this seems unlikely. Environmental and associated problems are not the result of brute numbers.

All of these population graphs play the same trick on your eye by using a vertical scale set by the current population. This is an understandable choice, but as a side-effect it makes the current growth look "vertical", when in fact for an exponential the location of the "knee" in the curve is purely an artifact of the vertical scale. If you graph the world population in millions, the current situation looks terrifying; if you graph it in billions, it looks alarming; if you graph it in trillions, it looks like we've got nothing to worry about.

Not sure if you've seen this series: http://www.youtube.com/watch?v=F-QA2rkpBSY (despite looking/sounding boring at the start, stick with it; it's really captivating and interesting), but it is amazing just how much 'small' growth (even 2-3% p/a) can cause things to double in much less time than you'd imagine.

Or if you haven't got the time to watch the whole thing (is close to an hour all in all), this touches on a couple of the topics the video covers: http://www.worldpopulationbalance.org/exponential-growth-tut... (naturally doubling every minute is on a much faster scale to the Human population!)

I was equally shocked to discover that over half the world population is younger than me.

Not exactly. There were 3.500m people alive then, and about 7.000m now, but because many of the 3.500m died and were replaced over those 44 years, you would actually be older than more than half of the world with high probability.

According to the figures provided, 77.500m humans total in 1967, 83.200m total now, so 5.700m had been born since then, but the population only increased by 3.500m, meaning 2.200m people had died since 1967. Without stronger data, it's impossible to say whether the people dying tended to be older or younger than a certain age, so it's not possible to say with any reasonable certainty what the actual fixed point is, or even the ratio of people younger or older than you.

Though, Wolfram Alpha reports the median age of the Earth to be about 27,6.

http://www.wolframalpha.com/input/?i=world+%7C+median+age

That assumes that the 3.5 billion people alive on 11/11/1967 are still alive today, which is not the case. The number of people born before 11/11/1967 and still alive today would be quite a bit less than 3.5 billion, and the number of people born after that date and still alive today quite a bit more.

(according to this model of early populations)

Probably not the best place to mention this, but I am in a way offended that BBC doesn't consider PoK or Jammu&Kashmir to be a part of India!

This is great, everyone should watch this.

Also the guy does fantastic chart presentations :)

To those concerned, a request with your provided info appears to only be sent to their servers once you arrive at the Results step (which itself is mostly just a recap of the previous step).

Yes, I'm not aware of any reason why my sex and country of birth are required here.

That probably wouldn't help a whole lot either since it's unlikely that this is based on a huge central repository of world births and their associated times. Does most of the world even track those?

You are clearly mistaking the BBC for some grubby commercial organisation.

Ta, Person 4,282,072,850.

In my city (Hamilton, Ontario, Canada), there is a 20+ difference in life expectancy between the most affluent and most impoverished neighbourhoods. Even within countries, averages mask deep inequalities.

Life expectancy varies with age [e(x), with x = current age]. The key question is, how long can someone who is your age now expect to live? In other words, in some places may be hard to make it to, say, 40 years old, but if you do you may have a better chance of making it to 75. I don't know about Bulgaria particularly, however.

I was born a little while north of you. What I would tell most guys born in that general region is: "quit smoking, drink less, and watch your diet". That should raise their life expectancy by a decade, I guess.

Probably will change by the time you're that old, I'm expecting.

Are you sure you used European style dd/mm/yyyy? I made that mistake the first time.

If you look at the the chart there is a large jump in the data. "Notes on the data: Only birth dates after 1910 can be accommodated and only countries with populations of more than 100,000 people are included. Where available, the UN's medium variant and average figures from 2005-2010 have been used. World and country population clocks are estimates based on the latest UN figures and growth rates. They may not tally precisely with other clocks because of the way this application is configured."

if you're more than 2 months from the future, also not.

I had this problem originally. It's not Chrome. :-)

I originally entered in my birthdate as 06/30/1980, but they are using European date style. As such, it would have to be entered as 30/06/1980 to make sense.

The 76 billons ones.

"Ditto for pollution"

I believe pollution per capita is highly correlated with per capita wealth (or income).

Is this accounting for immigration? The US has the same issue: the white population reproduces at barely above or barely below replacement (it varies), but immigrants have much higher fertility. And, weirdly enough, comparable infant mortality.

It typically takes two generations. The first generation of women that have the chance of higher education and a professional job have a much lower birth rate. Then once these women get into positions of power they show that it's possible for women to have children and a career introduce maternity leave, women's rights etc and the birth rate recovers with the next generation.

It's interesting to plot the position of each country in Europe in this cycle, from Scandanavia through Italy/Spain to Greece/Portugal.

For the 3rd world or 'human resource rich countries' - it's different. You have to look at the population in the industrial revolution 200years ago. People living on farms in the countryside had lots of children to run the farm, to provide for them in their old age and because many wouldn't survive. They move to the cities and have the same number of children - but more of these survive (however bad conditions in the 18C towns were - they were better than the countryside!)

Then as people become more prosperous they have less children and the population stabilizes - but at the new higher level

It will have to be checked one way or another. Either we as humans will have to (as in the case of China) or nature will take its course in checking the population. We can't grow at the rate that we are, while consuming the resources at the rate we do for much longer. Check out economist Thomas Malthus' "Malthusian Theory:"

http://en.wikipedia.org/wiki/Malthusian_catastrophe