On October 31 2011,the 7 billionth person will arrive on the earth, according to the UN.
Up until now, the world’s population has grown exponentially: It took over 127 years to reach 2 billion (1927); another 50 years to double to 4 billion (1977); and slightly under 22 years to reach 6 billion (Adnan Nevic, born October 12 1999 is the UN’s 6 billionth living person). It took just slightly over 12 years for the population to go from 6 billion to 7 billion. If population growth stabilizes at 1 billion for every 1 dozen years, we expect reaching 11 billion people by 2060. This predicts a dire future: There is no parallel growth in the necessary resources (especially water and space) to sustain a continually growing world population.
But don’t plan your move to the moon just yet! A more in-depth analysis predicts a different outcome. Population growth is heavily dependent upon birth rate. The trend in birth rate data predicts the world’s population might stabilize at 9 billion in 2050. From 1810 – 1930, the growth in the world birth rate was insignificant from year-to-year, showing very small increases. From 1940 – 1980, however, the birth rate nearly tripled – and combined with advances in our ability to increase the average life span, the world population exploded.
But since the 1980s, the birth rate has dropped slowly. This is most evident in the average number of children born to one woman. In 1950 the average woman of the world had 8 children (think back to the size of your parent’s or grandparent’s family). By 1980 it dropped to 4 children per woman. Currently the world’s ratio is 3 children/woman. Already 80% of the world’s population lives in countries where the birth rate is less than 3 children/woman. If this trend continues, the ratio would reach 2.1 sometime before 2050. This is no random number – but the exact ratio that supports the smallest growth in population. Projecting ahead, the exponential growth in population will slow down, getting us to 10 billion by 2085, according to the UN.
Ten billion is still an astronomical number (the moon is only 240,000 miles from the earth, for comparison), and supporting that population will not be easy. Not only do we have to worry about distributing basic resources – food, water, space – but we will need to take into consideration how population growth impacts our ability to secure or produce them. The good news – in my opinion – is that we have 75 years to curb our growth and continue to develop new technologies that will help with resource allocation. And, just learn how to live with close neighbors.