I agree!  I could not get my Dad (PhD in EE, BS in Physics, Professor, etc.) to pay attention to my PO concerns - until I sent him Dr. Barlett's presentation.  Then he said "OK, you win".  There are still the questions about the timing, the extent of the effects we may see, etc. - but he quit hiding his head in the sand!

I first watched Dr. Bartlett's presentation a few months back. It really helped things come into clearer focus for me. All of a sudden I could see the bigger picture and how everything is tied together. I plan on sharing it with anyone I can get interested when the subject comes up.

One of biggest contributions that I can make to the PO cause is to help raise awareness. Once enough people 'get it' (I would hope) that we can start to see more positive change. It used to be that we had front porches in our neighborhoods and (before TV. and AC) we would go outside after dinner to talk with our neighbors about important world and local events.

Wouldn't it be great if this were taught to our children in school in an age appropriate way? And much more that isn't, of course...

hmmm...that link worked for me.  :(  though the link below has some really cool extras in it.

FatherOf4 used to have a site called Flying Talking Donkey, which was a news aggregator and an interesting site.  He took it down a couple of months ago.

Hanson's paper is making the point that economic growth (measured as gross world product) has been increasing faster than exponentially for a long time, or more precisely that it can be modelled as an overlapping series of exponentials with rates that have increased with each characteristic epoch.

It doesn't say the same is true of population growth, at least recently, and certainly we're lucky that population growth is easing away from its previously exponential (in the recent past) and super-exponential (going further back) track.

But I really take issue with is the idea that because super-exponential growth has gone on for a long time, it's a priori plausible for it to continue for quite a while.  In fact, the more super-exponential the growth function, the less reasonable it is to extrapolate that way from the past!  In the extreme case, you could have a pattern of very little growth at all until the last 10 years, where you have hyperbolic growth taking off towards infinity in another 10 years.  Few people would suggest extrapolating on that basis.

As a side note, I'd bring up Jared Diamond's Collapse and point out that in many regional instances neither economies nor populations managed to maintain (super-)exponential growth.  Since until very recent centuries human history is a sum of generally isolated regional human histories, we would do very poorly to ignore these natural experiments now that we have in effect only one big population.

Now, I'm not arguing that economic growth as measured by world domestic product can't continue steady exponential growth, or perhaps even super-exponential growth, though I have severe doubts about the kind of Singularity Hanson appears to entertain purely from the models.  

(GDP/GWP may be a bad measure of economic activity going forward, but that's a whole other discussion)

But our ability to increase economic activity in that fashion is available only to the degree that we can divorce it from whatever physical limits the Earth presents us with. Nanotechnology, super-low-powered computing, virtual worlds (and the potential huge economies they could bring) are all wonderful things which may allow us to markedly increase our economic activity and personal utility ... but they don't do anything to solve the very pressing issues around energy and other physical resource issues (topsoil, water, etc.)  

Dropping energy per GDP is by itself of little use; there's no sign that rich countries are yet spending enough of their wealth on intangibles and services to stop increasing their total (or even per capita) ecological footprint.  We've been granted a demographic gift of a population that may stabilize on its own below 10 billion in this century, but that bit of luck will be of little use if we rely on luck (or price signals alone) to prevent the pain and dislocation of resource scarcity.

There's reason to believe that our population might not have been growing exponentially for a million years. Check out the transcript of this programme from the BBC: http://www.bbc.co.uk/science/horizon/1999/supervolcanoes_script.shtml

About four fifths of the way down the page they discuss a population bottle neck 70-80,000 years ago, based on miochondrial DNA evidence. It seems the human population may have numbered as few as 10,000 at that point. The time frame coincides with an erruption of the Sumatran supervolcano Toba 74,000 years ago, which would have had dramatic effects on the climate. That erruption was near the high end of the volcanic explosivity index, putting it at perhaps 10,000 times (or more) as intense as the erruption of Mount St Helens (if memory serves). For what it's worth, there's another supervolcano with similar explosive potential under Yellowstone Park. It seems to errupt about every 600,000 years, and the last erruption was 640,000 years ago. There are some things that make even peak oil look insignificant.

Human evolution happens to be one of my interests, Halfin, and talking about million year trends strikes me as a bit fantastic. One million years ago Homo erectus was running around just like any other animal making a living as best they could in their ecological niche. They certainly were not involved in any activities like those our species have engaged in from the beginning of the Holocene up to the present time.

Actually, there is good evidence that these same Homo erectus guys had thick, elongated skulls and large brow ridges because they (at least, the males) used to bash each other over the head to settle disputes (probably mostly over mating partners and territory). I won't dispute that a million years ago, these hominids were among the most dangerous predators then existing. Now, of course, Homo sapiens, having helped pushed Homo neanderthalensis into extinction, reigns supreme. And there is no doubt about what animal is the most dangerous predator on the Earth anymore. Taking the very long view in Geological Time, it would appear that Nature made a big mistake in the Pleistocene. Still, I'm sure that most of us are glad to be here even if the timespan for our continued existence is somewhat problematic--again taking the very long view.

So, maybe things haven't changed much.... Now we just prey on each other and the rest of the natural world.

I could provide hundreds of references if you like but don't ask. In any case, this tends to cast doubt on the source Robin Hansen you cite in your comment.

I wish our government had to hear him [mathematician Bartlett, not Roscoe]

Homo Sapien has a finite brain.

Most of the brain mass is consumed by emotional "thinking" (day-by-day survival, procreation, power, control, social status, etc.).

A thin layer, known as the neo cortex, is believed to be engaged in "rational" thinking.

Evidence is abundant (even though we each wish to deny it) that the neo-cortex can absorb only a limited amount of information for defining its own internal "frame" or model of the outer world (of surrounding reality).

1.If you grow up as an "economist", then you probably tend to "frame" or internally model the world around you in economic / Adam Smith terms (e.g., "The Markets" will provide, they always have.).

2. If you grow up as a political science student, you tend to "frame" the world around you in socio-political power terms (e.g., Only "voting issues" matter to my survival --kind of paraphrasing Bill Clinton here).
   
3. If you grow up as a geology / science student, you tend to "frame" the world around you in geological /scientific terms (e.g., e=mc^2, blah blah boring math model stuff --although this framing system is not going to get you far in the financial-power / political-power world because they don't and can't "see" or "hear" or "feel" the world in that way).

Government --as it is-- will never hear Bartlett because they (lawyers, financial power gurus, etc.) are incapable of framing the world's reality in those terms.

Picture your Congressperson reasoning the whole thing out:

"What do you mean population "growth" is bad? No. Growth is good. Greed is good. Population growth equals economic "growth". Economic growth means more tax revenues. Population growth in my Congressional District equals more power for the all important "me". Barlett's ideas defy the reality of my world and therefore he is clearly wrong. Not even worth debating it. Excuse me, I have an important meeting to go to. We're building another bridge to nowhere. Isn't this system grand? I love it. What's good for "me" is good for America, good for the world. That simple and sound truth is non-negotiable."

Just a note - this is from the APS Forum on Physics and Society (FPS). The newsletter you used to get was probably Robert Parks' "What's New" - that was sort of an independent early "blog" in reality, put out by Parks from the APS Washington office, but it was kind of divorced from the membership of the organization otherwise. I've been a member of the FPS forever, have written a few letters and articles for the newsletter; it's quite grassroots and it's always been very activist. You could learn a lot, particularly about nuclear power and security issues, going through their archives.