The human population of planet Earth will be in decline soon, but what will happen to all the people, and how fast will it happen? Well, in the most vulgar of terms, we are killing each other off in war and genocide at an increasing rate already. It's impossible to disconnect what has happened in Libya, Egypt, Sudan, and Somalia, among many others, from the reality of decreasing resources upon which our population depends. Actually I think it's telling that the most obvious societal deterioration of today is centered in the birthplace of agriculture 10,000 years ago - agriculture marking the beginning of our journey into questionably-sustainable population densities. Just because we're not fighting over bread in the United States doesn't mean that the net movement of human population dynamics isn't already crossing the max population peak at the global level. And in that context, when one culture is living on comparatively easy street, other cultures are already suffering. We burn coal to make ice for us, even our unemployed do, but most people have trouble finding clean water to drink.
Part of the answer to that question also lies in the fact that we will (quite naturally) redirect energy from less critical activities into producing and feeding babies. Considering the amount of energy dedicated to unnecessary activity in the industrial world, we could potentially keep our numbers heading north for some time to come. But the industrial world was not where the population growth was coming from even a decade ago. A household of "dinks" (double income, no kids) in Atlanta who make 150K between them, and maintain a vibrant social calendar, might assume that they can't afford a baby, where the tiniest trifle of first world philanthropy, let's say the equivalent of an extra chicken and 5 lb sack of rice per week, could be translated into another child in a very poor country. When it comes down to giving up the cell phone or the annual Heifer contribution, those guilt-sponsored children in poorer nations may be hit harder and faster than anyone. Matter of fact I think it's safe to say that that trend is already underway. We've dumped both in this house.
When you begin to realize that agriculture and affluence, and the concentration of people and resources they underwrite, are really the unsustainable bit, it's a short leap to the realization that we don't need more city-dwelling farmers. Sorry guys, maybe that seems cold, but...
In nature, there is no such thing as an invasive "pest" organism. Not for long anyway. In a healthy ecosystem the suite of resources on offer in any given system is being fully utilized by the members of that healthy community. There is no excess with which to sponsor a new problem. But if you cook more food than you need for dinner someone is going to eat it. Whether that's crazy old Uncle Pete stopping by unannounced, or a new breeding pair of rats that smelled the unmistakable aroma of excess wafting by, the outcome is rarely pretty. In the case of what we often consider "invasive species" in the landscape, the invaders are simply filling an open niche, almost always created by us. If we humans were living at typical background populations and energy regimes, we wouldn't be able to create enough disturbance, or add enough excess energy, to a system to sponsor the pest organisms. They would pretty quickly find a balance with the recombinant ecosystem. Consider the implications of this paragraph in your garden.
As an example let's consider the problem of kudzu in the US southeast. Problem? Really? Kudzu is a soil-stabilizing, nitrogen-fixing, top notch fodder plant that produces copious amounts of biomass. Any southerner would second that last part, although the first 3 descriptions might be more elusive! Kudzu, like any plant out of place, is simply an opportunist, and what oil-powered human activity has made readily available in the US southeast is an enormous niche for a plant like kudzu to fill. Fragmented forests, worn out soil with almost no biological activity in it, eroded landscapes - we freakin' NEED kudzu to do what it's doing. Yet we spend millions and millions a year fighting this "invasive pest" plant. (You invasion biology types think about who makes the money from this "noble" fight against such a dastardly enemy.) As energy descent puts the brakes on our meddling ways kudzu will find its place in a recombinant but healthy, balanced ecosystem. So will the rest. Disturbance opens the door for invasion, and out-of-balance nutrient and mineral cycles maintain it.
So what happens in Nature when one organism gets out of control? Well, in time another organism or guild of organisms will evolve or step in and utilize it as a food source, or its own food chain will collapse from the pressure. The classic example in ecology is the island populated by deer and wolves. As the deer numbers surge, so do the wolves, but eventually too many wolves will crash the deer population. The deer's food chain and reproductive strategy simply can't make deer fast enough to keep up with the pressure of the growing wolf population. And so the wolf population starves and their numbers crash to a point that the remaining deer can now support. There is almost always a remnant, but it can be devastating for the species.
For any of you who have read Toby Hemenway's book, Gaia's Garden, or who, luckily, might know the Bullock brothers personally, you should recall the story of the cattails being wiped out by the growing muskrat population in the Bullocks' recently restored marsh. Confounded about what to do to bring the system back into balance, (and get some of those tasty cattails back into their diet), the brothers decided to do nothing and let Nature run its course. For a couple of years they were unable to harvest a single delicious young cattail shoot for themselves because of the greedy muskrats, but then something extraordinary happened. Their intuition paid off, and a group of otters showed up to feast on the muskrats! Oh, and some eagles moved in to enjoy the bounty as well. So now, instead of having a muskrat problem, they were enjoying another whole link in the food chain that their system was supporting! Not to mention the cattail shoots they had been patiently waiting for for the last few years. Anyone who has read my essays on food chains will know that adding a top predator to the food chain means that an exponential gain in systems energy is represented by the otters and eagles. That's what allowing Nature to take care of things accomplishes. The conventional option would've been to trap and poison the muskrats, and the reward would have been a shorter food chain containing less embodied energy. That's what human intervention usually accomplishes. Systems poverty. And the need to pay for the energy that Nature would've offered for free.
Even the ecologically-motivated act of restoring the Bullock marsh caused a systems disturbance and allowed an invasion of new species to occur. Many people consider the cattails themselves to be a weedy pest organism, albeit a tasty one. Had the system stewards kowtowed to conventional thought the newly evolving ecosystem might have been cut short long before the otters and eagles arrived. Poisonous sprays might have been deployed against the cattails in an effort to achieve a "more natural" marsh ecosystem. But by changing the way they thought about such things, the Bullocks turned the problem of the cattails into a regular food source, thereby checking the expansion of this "weed." By acting as they did, in line with Nature's ways, they lengthened the food chain and the energy contained within. The muskrats represented another link in the food chain, and had the brothers been more desperate, they probably could've exchanged their cattails for muskrat etouffe. But by taking their lumps with the cattail shoots, and letting the system evolve naturally, they added two top predators and an exponential increase in systems energy to their farm. It's not necessary to think of each new link in the food chain as a food source for ourselves, but each new link does mark a large jump in overall systems energy. And that energy, properly managed, can be translated into a large jump in productivity of the human food system buried within the larger ecosystem. It's fertility.
One weed then. There is really only one weed on Earth today. We all know his name - Homo sapiens. And fossil fuels are his abettor. Really that's the difference that defines the distinction. More appropriately we might think of the invader as the industrial human mind, more than Homo sapiens himself. Homo sapiens was at one time just another animal member of another healthy ecosystem. Ten thousand years ago a visitor from outer space would've had a tough time identifying what the dominant life form on Earth was. Humans participated with their ecosystem, and lived within its background energy. Even if they did have curious habits of making art and jewelry, and used fire to modify their food production systems. Since then, he has moved onto every continent, and into some of the most inhospitable climates Earth has to offer. He dams rivers, and depletes underground aquifers. He poisons air and water with his industry. He levels forests and plants monocultures that require more expensive inputs every year to maintain. His presence on Earth is prominent. Geologists have even considered a new geological epoch called the "Anthropocene" to delineate the impact of industrial humans from the rest of human history during the Holocene, the time since the end of the last ice age, when humans moved out en masse to colonize the planet . It's that prominent.
Now, it's not that what we've done is monstrous or aberrant. Actually I think, given our cleverness and the presence of millions of years of stored up solar energy in the form of oil and coal, the industrial age, followed by human population overshoot and collapse, was absolutely inevitable! But the time has now come to recognize that the energy that created that population and affluence can't simply be replaced by our own manufactured technology. Sure, with the fossil energy we have left we can build things like solar panels and hybrid engines that will lengthen the amount of time it takes to descend, at least for the owner of that individual technology, but ultimately that energy will be unavailable, and the maintenance of that high technology increasingly unrealistic, and we will be back to where we started in terms of energy availability. Wiser perhaps, for what we've seen, I mean, if nothing else permaculture was a byproduct of our high energy society, and permaculture will allow us to maintain a somewhat higher standard of living than we did pre-industrial revolution. Applying permaculture principles, we can create food systems that largely take care of themselves, and lifestyles that more closely fit our energy descent reality, and that will allow more time to engage in other activities, like art and community functions. But if we don't take the lessons of the past 200 years and apply them to our lives in low-energy ecological terms, then we can probably expect our children to toil in the fields, have chronic degenerative ailments, and be more or less consistently malnourished, not to mention bored senseless, as the remnant of our former glory.
And the ones who can't or won't adapt? They will become surplus and probably a new food source. Whether that's applicable in a literal sense - if the collapse following the overshoot is abrupt and there is a catastrophic die-off, or whether the collapse comes in the form of fewer children every generation until we reach a sustainable human population, who knows. But we will be returned to balance one day, just like kudzu, and probably not too far out. Plenty of isolated human populations, when confronted with their own version of energy descent, turned to cannibalism to survive. Descriptions of explorers who discover such cannibalistic populations usually talk about meek, deranged, frightened, and malnourished people before them. I imagine it would take a lot out of me to have to turn to that too. If we catch it in time, our soylent green will consist of nothing more than slowly exchanging humans, generation after generation having fewer children, for a wholesale increase in other biodiversity. Rebuilding our life support systems that is. But knowing us, it's far more likely that entire populations of humans will be leveled in the attempt to keep things "normal." After all, that's what we're doing in the Middle East right now, whatever more palatable term it's being given...
I read the other day that the cost-cutting of the prior hundred years, in relation to first world affluence, has been completely wiped out in the last eight. This was the CIO of a 106 billion dollar investment firm talking too, not some doomer from the blogosphere. Amazing how quickly the dream world can evaporate when confronted with the laws of physics. Practice your scales and chords this week.