Population Growth -- An Accessible Topic

As a companion piece to my global warming dilemma, I offer this. I attended a population growth session at a California Science Teacher's Convention a year ago. The presenter showed a video depicting the growth of the human population from a few thousand BC to the modern era. It was a map of the globe with spots appearing for each million people. Pretty impressive.

The rest of the session used prepared materials, CDs and literature to describe how serious population growth is. We ran a nice lab on water pollution, implicitly resulting from too many people throwing stuff in the rivers. Excellent demo.

But here's the problem. I gently asked the presenter if she were aware of current population trends, especially the rate of the rate of change. (That would be the second derivative of the growth curve, although I didn't use that term.) I made the point that populations are found to grow along S-chaped curves, with the top of the S showing the slowing of the rate of increase. The population levels off at some point which can be predicted if one looks at the curves and how they're changing.

In the case of humans, this leveling off is already happening. We're close to the top of the curve. Growth will stop.

She was unaware of any of that. Since she was using packaged materials from an advocacy group, she hadn't encountered the thinking of mainstream demographers. Since all of this was under the aegis of CSTA, attendees would naturally feel that the lecture has a scientific imprimatur.

I tell this story because it is an example of not-completely-baked science and an emotional video telling an inaccurate story. As an educator I was able to assess that science. So far I cannot do that with anthropogenic global warming.

Suggestions?