Population 7 billion

Hello Everyone,

            Last week, while waiting for an appointment, I came across the January 2011 issue of National Geographic. It was the cover’s title of “Population 7 billion” that caught my eye. The normally unbearably long wait went by very quickly as I found myself lost in the article. The report noted that population levels are currently at around 7 billion and will continue to climb to 9 billion by 2045. It predicted that upon reaching 9 billion, population growth would cease and remain fairly constant around the 9 billion mark.

            How did National Geographic arrive at the trend of population growth to 9 billion and then remaining constant?

            They observe that while fertility rates (e.g. the average number of children born to a woman over her lifetime) have declined to approximately the replacement level (fertility rate needed to maintain the population) of 2.1, many nations have a disproportionately large amount of children and adolescents. The glut of children is an effect of previous fertility rates that were overly high. The consequence becomes that when these children become adults, they will contribute to increasing population growth even if the fertility rate is at replacement level. National Geographic predicts that this trend will conclude at around 2045 as by then there will have been consecutive generations with stable fertility rates and thus population stability will be achieved.

            It was an interesting read, here’s the link: http://ngm.nationalgeographic.com/2011/01/seven-billion/kunzig-text/1

It got me thinking; can earth support the 9 billion inhabitants predicted for 2045?