I discovered Diamond's essay for the first time several years ago, while I was reading up on human health (in an ongoing quest to improve my own). I was intrigued, and eventually convinced, although I know that there are important points to be made against Diamond's pessimistic take on agricultural civilization (e.g. the arguments raised by Steven Pinker). That said, this post is going to be my version of Diamond (dumber, shorter, and with less references). I wrote the original version of the post in response to a friend, who forwarded an article lamenting recent decline in the birth rate among nations of the First World. I have seen several such articles, all of them implying that social upheaval (broken economies, crime, etc.) is owing to a lack of babies, a lack that these writers (if I understand them correctly) seem to ascribe to widespread laziness. My fellow First Worlders are not "putting out" as industriously as they should, and will be rewarded with the implosion of their padded social safety nets (as fewer kids exist to care for more and more parents, aged and helpless). I doubt this. Following the train of thought developed by Daniel Quinn, I further doubt that a reduction in human population worldwide would be a bad thing (necessarily: I am not saying that it would be great, either; it might, however, be natural -- as good or bad as rocks, waterfalls, and bacon). Here is what I wrote, with a little minimal editing.
I think population reduction is a healthy response to imbalance in resources. We simply don't have the goods to fuel endless growth (in people or the things they require to exist, things like food, water, shelter, clothes, entertainment -- unless we are willing to drastically reduce our expectations in these areas). We are adjusting to several environmental factors, e.g. globalization (and concomitant competition for increasingly scarce resources), climate change (which may or may not have anything significant to do with us), and technological revolution (which has addicted increasing numbers of us to luxuries like running water, food that someone else prepared, housing that someone else built, gadgets that someone else invented and mass-produced, and lifetimes spent working narrow careers with companies that don't go belly up).
Historically, the agricultural model for human survival has been to reproduce like insects: we made lots of people -- lots of sick, blind, stunted, relatively weak people -- and took over from the hunter-gatherers (who were healthier, sharper-sighted, taller, stronger, and even more mentally capable than we) by sheer force of numbers. One familiar episode in this ongoing saga is the displacement of the American Indians by boatloads of European riff-raff (whose guns, germs, and steel paved the way for them to become a dominant force worldwide). Indians were healthier (as individuals), more sustainable (as communities), and less numerous than the immigrants who replaced them. We were the mites and moths and hornets who overran their beehive. Now, it's our turn to be overrun. Maybe the result will be just another opportunistic parasitism, but I don't know. I get the feeling that other societies are collapsing too: people are living shorter and sicker lives all over the world; standard methods of producing the energy modern civilization requires to exist are failing; economies are imploding (not just in Europe and North America: India, China, and their neighbors are also looking less than robust these days). I think we may just have to learn to live with less; and that may mean that there will be less of us. Our old methods for solving these dilemmas are (1) plague and (2) wars: the last century saw us pushing (1) away while embracing (2) with all our might. I think we might be due for a switch, with (1) returning (in the form of rampant diseases of civilization: diabetes, syndrome X, autoimmune disorders, obesity, failure to thrive, infertility, heart disease, stroke, cancer, etc.) and (2) fading (as we stagger away from a century of vicious fighting). I could be wrong, of course.
Since this is a topic of recurring interest to me, there will be more about it on the blog. I am not done with it yet by any means.