Sunday, December 16, 2007

Population Density

There is a lot of discussion these days regarding resource utilization by the human race and sustainable consumption. Jared Diamond wrote a book related to this called Collapse in which he explores the reasons some societies succeed and others fail. Reading this made me think about how many people could be sustained on earth on an on going basis and not exhaust our resources.

To start with let me say I have no idea. Also, there are a lot of factors which should be dealt with to make an accurate prediction of a sustainable world population level for humans and I’m not sure such a thing is even possible. But out of curiosity I thought it would be interesting to compare some population levels just to get a feel for whether or not there is any hope for us at current population levels.

First let’s look at Easter Island. It’s a tiny Island in the South Pacific about 63 square miles in area and 100s of miles from anything else except water. To put that in context that’s about twice as large as Manhattan. This is the Island where the funky statues where built that are featured in movies and cartoons that have scenes on remote tropical islands. At one point Easter Island supported a relatively successful society that was able to be productive and innovative enough to produce big funky statues. Eventually they chopped down all their trees (primary natural resource) and their society and population collapsed. Some folks estimate that the high water mark for Easter Island population was around 20,000. (I think others think it could have been higher.) That’s a population density of 122 people per km2. So, 122 people per km2 might be too many to sustain; at least on a small island with limited access to resources not immediately on the island. (Note the parallel between Easter Island and Earth in general.)

Next let’s look at Haiti. This is another island nation one could argue has failed as a society. It is not as remote or small as Easter Island. It has a population of around 9 million and about 316 people per km2. So, I guess 316 people per km2 is too many to sustain.

Interestingly the UK, yet another Island nation only with several hundred years of relative success, has about 256 km2. Hmm. Maybe the world could support this level of population density. Of course one might argue that part of the reason that the UK can support that level of population is because they use a lot of resources from other locals. For the world, we have not figured out a means of harvesting resources out side of our “little” ball. So we may not want to just assume the 256 km2 is a sustainable population level.

Now for the United States. The United States has about 33 people per km2. Much lower than any of the other societies noted and even though the U. S. is highly integrated with the World economy as is United Kingdom and we have a lot of issues we seem to be humming along pretty well and it would seem that we could sustain our society for some time as long as we solved some problems like securing sustainable fuel sources and global warming and fixing unsustainable entitlement programs like Social Security in its current form. So, our world might not be able to sustain 100, 200, or 300 plus people per km2. But maybe 33 people per km2 is doable.

Finally, the whole world has about 45 people per km2. Now this is a ridiculously simplistic analysis if it can even be considered analysis but the conclusion I draw from this is that our current population is not at such a level that we are destined to a major failure. If it where above like 100 km2 then I think you could say we are definitely in trouble. But our current population might be manageable. We probably don’t want to have it grow a whole lot and we do have big problems to solve but there is still hope that the world population can survive and thrive at current levels.,_Iowa

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