
The Most Important Statistic in the World - llambda
http://www.impatientoptimists.org/Posts/2013/09/The-Most-Important-Statistic-in-the-World
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lutusp
Actually, from a scientific standpoint, the most important statistic in the
world is the population growth rate. Put another way, the most important
change is, not how many of those born survive into adulthood, but how many
people are born to begin with.

The reason? The infant mortality rate is arithmetical -- it's a number that
can become bigger or smaller, but without any secondary consequences. By
contrast, the population growth rate is exponential, because babies grow up
and have babies of their own. That means even a tiny change in the growth rate
has far-reaching consequences for all people everywhere.

And, given that the earth is finite in size, and given that we want to design
a sustainable life on planet earth, what should the growth rate be? _It must
be zero, and it isn 't_.

[http://en.wikipedia.org/wiki/World_population](http://en.wikipedia.org/wiki/World_population)

Quote: "The growth rate peaked at 2.2% in 1963, then declined to below 1.1% by
2012."

At the 2010 rate, the world's population would double every 63 years.

If that rate didn't change:

    
    
        (year, population in billions, percentage compared to 2010)
    
        2010:   6.80  100%
        2020:   7.59  112%
        2030:   8.47  125%
        2040:   9.46  139%
        2050:  10.56  155%
        2060:  11.79  173%
        2070:  13.16  193%
        2080:  14.69  216%
        2090:  16.39  241%
        2100:  18.30  269%
    

Of course, the rate will change -- it will be driven down by mass starvation
and disease.

