VHEMT is a plan to improve this place (Earth) through the practice of reducing the human population. "May we live long and die out." The idea of the movement is that a collection of individuals will refuse to reproduce -- if everyone joins the movement, our species will die out. It's obvious, however, using the means that VHEMT advocates are actually using, that at best we will accomplish a population reduction, so I am going to talk about the joys of population reduction for an entirely different goal.
Well there are obviously a zillion socio-cultural reasons. Everything from "because all my predecesors did" to "because I have so much love to share." All of these reasons are perfectly legitimate for an individual, I'm sure. I mean, who wouldn't be excited at the possibility for immortality and the chance to share the entire process of growing up with your own offspring? If I were the only person that mattered, it's a simple matter of satisfying some logistical constraints, and then I'm certain I would find fatherhood to be an immensely rewarding experience.
But all that's bullshit. The reason we reproduce is quite obvious -- if all of our ancestors hadn't reproduced, we wouldn't exist. Since we reproduce by making nearly identical replicas of ourselves (i.e., all of our children are human), there's a simple inductive proof that the species exists if its members breed and doesn't exist if they don't. "I think therefore I am" might be fun to think about, but "I am because my kind breeds" and its corollary "We breed because we are" are the real cornerstones of what it means to be this peculiar entropy-defying construct that we call life. This facet is something we share with viruses and amoebas and even (to some extent) stars. We are nothing but a pattern of atoms, and this pattern can only exist if part of its nature is to encourage similar patterns to exist. If, when a generation of stars die out, it did not perfectly set the stage for another generation of stars, there would be no stars anymore.
So let's assume that mankind is reproducing exactly at replenishment rate -- when one person is born, someone else dies. If there are only ten people in this equillibrium, a single accident or war could easily destroy the entire species. If there are a thousand people spread out all over the planet, a single virus could still destroy the entire species because we wouldn't have the requisite genetic diversity. And so on. It is clear that existence defines us not only as a species that reproduces, but one which reproduces beyond replenishment level. We are not just a little fruitful. We multiply.
With multiplication comes all sorts of auxilliary benefits that make us more hearty as a species. For example, more people can cover more land, making our species more resistant to natural disasters. More people also means more spare capacity for scale benefits. If we have a community of a hundred and ninety of them are farmers, the remaining ten cannot start a strong scientific tradition. But if we have a nation of a hundred million and ninety million of them are farmers, that leaves ten million to form communities of engineers and leaders, all of which are essential to the survival of our species.
The problem is that all of these effects act very strongly at the small scale to encourage breeding. If there are two humans, they must embark on a prodigious breeding program. Their children will continue this breeding program (to their advantage). But the problem is that none of these effects scale infinitely, and even if they did, there are intermediate barriers we have not bested.
To understand the long-term survivability of a species, you have to consider the effect of time (well, statistical reality) on the elements which support us. Over the span of a thousand years you will see events that will destroy islands (consider Atlantis). Over the span of a million years you will see events that may destroy planets (think dinosaurs). Over the span of a billion years you begin to worry about the health of entire star systems.
So if you want to live more than a thousand years, you better breed fast enough to colonize the western hemisphere. If you want to live more than a million years, you better breed fast enough to get off this planet. If you want the species to become immortal, you better breed fast enough to colonize several star systems (and rinse/repeat).
So where does this put us today? We've completely filled up Earth, so from a species survival perspective our next goal is to jump planets. It's clear that ultimately breeding will be a boon to this endeavour. Even in the short term it has a tremendous advantage in terms of the spare capacity we are producing today that will help us build the space ships and so on of tomorrow.
The trouble is that we've reached and breached the point where diminishing returns overwhelm the breeding advantage. Let's do some back-of-the-envelope computation. Imagine it takes 10% of the population for food production. Imagine it takes a hundred million scientists, engineers, managers, and poets to run a respectable space program. So it takes on the order of 110 million people to prepare our species for the next step. Well you might imagine that having six billion people, the five billion or so who aren't involved in every day survival would give us enough surplus capacity to run a stupendous space program, right?
Except that's not what our surplus capacity is doing. The parts that aren't too busy getting killed off by famine and poor leadership are busy killing eachother off. Rather than trying to find out how to get off the planet -- something that is guaranteed to be important to the survival of the species -- all of our energy is focused on how to continue to support such a huge surplus population. Rather than farming in a sustainable way that will aid our survival as a species, we are farming in a breakneck "oh shit" strip-mining style in an attempt to guarantee our survival as a generation. Having this many people means we have to deal with the problems of famine and war and pollution and resource exhaustion that come with an overpopulated planet. We are so caught up in crisis after crisis that we have become unbearably short-sighted.
The worst thing is that no one is focused on survival of the species. Our species would do just fine if 5 billion people disappeared tomorrow. Oil crisis? History. Wars? Well, you've gotta kill off the right 5 billion people here folks (*cough*Israel*cough*). But the point is that we're focused entirely on how to make that not happen. Rather than saying "Well, the species will survive if we spay and neuter," we are focused on the fact that our generation will survive if we can just find a way to support 6 billion people driving 30 miles to work every day once the oil runs out.
For a little allegory to the whole situation, look at how NASA is competing for resources with the DoD. NASA might save the species. The DoD might save our cheap access to oil. Right now NASA's been so thoroughly gutted that they've been making headlines for a solid week with Stardust. I'm sorry folks, but if we're abandoning yet another space station to the oceans (mark my words), it's going to take something a little more impressive than a $200M unmanned probe with "cheaper" in big bold letters at the top of its mission statement to convince me that NASA is not dead.
The terrifying thing is that a lot of those geologic timescales are becoming all sorts of whacked out. It may be a million years before another asteroid slams into us, but it's going to be less than a hunderd years before global warming makes it impossible for our planet to support 6 billion people. What are we going to do then? We'll have a big die out (for lack of any other choices) and all of the ensuing memetic viruses will be staggering. When shit really hits the fan, and it's obvious that billions of people will die over the next decades, do you think they'll go quietly into the night, or do you think they'll take the planet with them?
It may be a million years before another asteroid slams into us, but it's going to be less than a hundred years before WWIII comes home to roost. Think about it.
The funny thing is, Earth (the theoretical beneficiary of strict VHEMT practices) doesn't give a shit. We can strip mine the entire top thousand feet of the surface. We can extinguish every plant that grows. We can engage in thermonuclear war. Earth doesn't care. In a billion years you'll have to look twice just to tell we were here. It's us who are alive during The Great Breeding Calamity who pay the price. And if we don't survive it, it's the entire species bearing the burden. But -- trust me -- Gaia won't shed a tear one way or the other. Anything we don't kill off today, she was already planning to kill off tomorrow.
I don't want the species to die out folks. I think humans are pretty awesome, and I want to see us colonize the universe. But if we're going to be doing anything at all cool, we need to do something about the fact that right now we have a zillion people in a boat big enough for a half zillion people. We've got a *really* impressive bucket briggade here, but it's just not gonna cut it much longer. We're not ready to leave the planet yet, but we're real real close to that point where we don't have any other choices.
So for everyone's sake, use condoms. And while you're at it, spay/neuter your Catholics.
Really, barring thermonuclear war or unforeseen near-term encounters with space objects (rogue planets, asteroids, aliens), I think our species will survive the next thousand years. And we'll probably learn from the events of the next hundred years exactly the lessons I'm trying to impart here: we are shitting in our own food bowl every time we allow the population to reach these levels. And eventually various memetic coping mechanisms will be introduced into the populace (perhaps abstinence, or war, or spay/neuter, or pacifism, or Mars colonization). But we'll learn 'em bloody-like while the writing is on the wall and we've all got eyes.