Population Size =/= Consumption

     As Matt talked about in class and I previously mentioned in this blog, one of the major causes behind conservation issues is human population growth and consumptive demand. In December 2012, an editorial was published in Conservation Biology discussing just that (Allendorf & Allendorf 2012).

     It was short, succinct and well written. It explained the causative factors behind the population boom of the past two centuries and how it will end within 100 years. Their view of the future was a reasonably positive one as they provided concrete ideas on how we can address population growth and consumption now in order to minimize conservation issues in the future.

     According to the editorial, the human population became an environmental problem only in the past 150ish years. Prior to the 1800s, mortality and fertility was high. People lived to an average age of 35 and each woman had on average 6 children. The world’s population was about 1 billion with a minimal environmental impact.

     Then in the 1800s and 1900s, medicine and hygiene improved. People began to live longer and their children had better chance of having kids of their own. Fertility rates began to fall from 6 to 2.5 kids per woman. According to the article, fertility levels stabilized in the late 1800s in developed countries and around 1950 in others. Because women could be reasonably sure their kids would survive to adulthood, they gave birth fewer times.

      By the early 1960s population growth rate peaked. This means that while the world’s population is still rising but it isn’t growing nearly as fast as it once was.

     With regards to the future, the authors suggest that population growth will peak by 2100 at around 10 billion. Furthermore as fertility rates are lower now than in the 1700s, it is likely that the world’s population will decline slowly throughout the 22^nd century.

The authors seem to be describing the trend shown here...

     The authors also provided suggestions to deal with conservation issues by addressing the root cause of population growth and over-consumption:

     1)      Support family planning and contraception. This will help women control the number of children they want to have, and in turn minimize population growth.

     2)      It is not population size but spatial distribution that matters – therefore work to concentrate populations in centers away from sensitive environments.

     3)      Consumption is not correlated with population size but rather with the number of population ‘units’ (households) present. Therefore seek to reduce consumption by providing social and economic benefits to these population ‘units’. Make consumption reduction matter.

     I found these suggestions intriguing. The idea that it’s not the number of people that matter but where they are and how they organize themselves is interesting – consumption is independent of population size.

     Furthermore their prediction that populations will stabilize and even decline, it changes our perspectives on conservation. I think dealing with a constant predictable pressure would be better than the endless upward trend we are experiencing now.

Allendof, T. D., and K. Allendorf. 2012. What Every Conservation Biologist Should Know about Human Population. Conservation Biology 26:953-955.