Seven billionth person? Not quite!
The Sunday Nation
Nairobi,
06 November 2011
On Monday, 31st October 2011, the population of the world reached seven
billion. Many countries around the world designated the first baby born
on that day as the symbolic seven billionth person.
That designation was erroneous for two reasons. First; it is estimated
that about 135 million babies will be born this year and 57 million
people will die. Therefore, in 2011, the world population will increase
by about 78 million. Now 135 million births in 365 days comes to about
370,000 per day or four newborns every second. Clearly, it would be very
difficult to say which one made the seven billion mark.
Secondly; even if we were able to identify the specific baby that makes
seven billion people, that wouldn’t be the seven billionth person! The
number of people who have ever lived is a lot more than that – it is
estimated to be about 106 billion. We missed the opportunity to
celebrate the 100 billionth person a few years ago!
Still, we must stop and marvel at that seven billion number. If all of
us stood in line holding hands, how far would we reach? Allowing a space
of about one metre per person, the line would extend to about seven
billion metres, or seven million kilometres.
But we must bear in mind that not all the people in the world are
adults: some are newborn babies who need less than half a metre of space
in the line. Indeed statistics indicate that about a quarter of the
global population is below 10 years of age.
Therefore, we can adjust the length of the line by assuming that 2
billion people will need only 0.75m each in the line. This brings down
the length to about 6.5 million kilometres. That’s very far: the line
can go to the moon (380,000km away) about 17 times!
After appreciating sheer size of the world population, we must now ask
the more pertinent question: will the Earth ever fill up with people?
The way things are going, perhaps we don’t have to wait very long for
that to happen! Or won’t we?
It is estimated that the world population reached one billion in the
year1804, then it took another 123 years to touch two billion in 1927;
then 3 billion in 1960; 4 billion in 1974; 5b in 1987; 6b in 1999 (when
we were all preoccupied with the millennium bug that never was) and now
finally 7b in 2011.
Clearly, the period between any two consecutive billions has been
reducing quite rapidly. However, it appears that we have reached a
turning point. The duration between the 5th and 6th billion was 12 years
and so was that from the 6th and 7th.
This is quite encouraging. Indeed, the United Nations predicts that the
world population growth rate will continue declining and eventually
start decreasing within the next 100 or so years.
Three projections have been calculated. The median estimate predicts
that the world population will peak at about 9.3 billion in the year
2075. From there, the number of people will begin to drop. That’s good
news, isn’t it?
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