In the high altitude tropics where I live the daytime temperatures are in the 60's to low 80's all year round. 140+ inches a year in rainfall mostly well distributed throughout the year. Stuff really grows and biomass abounds. As far as I can survey, I have about 1500 Ohia trees ranging from small and immature to nearly 3 feet at the butt, with the average size of perhaps 8. I have over the last year planted Koa as well in various places, several hundred trees. Most are doing well. The Ohia are prodigious soil builders requiring little in nutrients and producing large amounts of heavy leaf mold throughout the year. No wonder they are sacred here. They are the real backbones of the forest that the whole island system is built on.
Early on I built a couple of stations in the forest to measure the quantities of biomass dropped per square foot. Quantities are significant. With these and other estimations it is fair to assume 20 tons an acre in carbon rich biomass is produced annually. This seems to be consistent with other local crop yields of taro or sugar cane, or at least is sensibly in the credible range.
So, perhaps that sounds like a lot, but only a portion of that is carbon, and only a portion of that is sequestered. Some becomes wood in trees which is relatively longterm storage, a good part of it rots giving off CO2 and CH4, not so good. So, the actual pumpdown in the amalgam is probably only a 3rd of all that, or about 20000 pounds.
So, what does that offset, really? The answer, of course, is nothing, as the the "ecowankers" and others are still flying around the world raising awareness about global warming. But, minding my own buisness, the figures are different. So, what is my allowable consumption to be carbon neutral? Well, roughly 200 gallons of gasoline a year, or 4000 lbs of wood in the woodstove, or elsewise in consumption in the mix. Of course here it gets very complicated, and it gets tempting to cook the books. Personally, I think the easiest thing to do is to scale it all in gross dollar consumption because the spending of every dollar has a carbon impact at this point, and the price of a gallon of gasoline is probably the most accurate measure of the real impact of a purchase, as fuel is one ingredient in everything we buy. If I assume 200 gallons of gasoline at 3 dollars a gallon as an average(since I don't burn that much gasoline) we have 600 dollars of consumption: if we assume that fuel is at least 10% of the cost of any purchase, conservative indeed--this gives me a consumption level of +/- 6000 dollars a year at current valuations as what I'd see as the upper allowable limit of personal expenditures. Of course this is a little over twice of global GDP so I'm living pretty high on the hog. A good number for a lot of reasons: 3 acres per person, perpetual permaculture, living under one's federal standard deduction so tax money doesn't directly go to undermine one's effort(another topic). At the moment with world population where it is there is almost 5 acres per person on the planet so the effort is sensibly ethically dependable. . .3 acres per person in agriforestry permaculture with cash expenditures not to exceed 6000 dollars a person for annual expenses to me seems to be a very good estimate of what sustainable really means. It is indeed do able, and of course, central to the theme around here, is a strategy that makes the forthcoming economic collapse of pretty small consequence. . .
Thoughts? Obviously unless you're living very sustainably off the land itself this isn't achievable. 5 gallons a week will not run a homestead and drive you to work. It will however, power a homestead alone. The immediate implication is that any functional homestead must provide both food, infrastructure, and income to be sustainable. Going elsewhere to earn a living is prohibitably ineffient and something we'll need to change.
Let me point out as well that the forest here is improving. This property is moving from a "natural" state to an "enhanced" state. By careful stewardship the output and carbon cycle of the land can be greatly enhanced. Careful applications of soil ammendments, tree husbandry, the introduction of biodiversity(koa especially) and biochar promise to move me from carbon neutral to into the plus column quite rapidly. Of course to then increase my standard of living is counterproductive--restaint, remember?--but does demostrate that this small living can work and provide for a lifestyle that indeed moves in the right direction. More on these techniques in the next few days.
UPDATE and AFTERTHOUGHT:
So, what this all means is that the average N. American couple will need to pare back consumption and expenditures by 80 to 90 percent. This is a lot. A lightbulb, casual recycling and a spiffy new Prius isn't going to cut it. Funny that I would find that number to be applicable because -- http://www.reuters.com/article/environmentNews/idUSTRE51Q22X20090227 -- these folks have come to the same conclusion. I don't see any way around it.
So, really, what gives? Are we really really right there at the brink of the Malthusian Nightmare? Yeah, I guess so. Yeah, I really think so. Honestly, I've been trooping and working on this stuff for years and it's caught me by surprise. But, all in all, this how it works. Life is what happens before your ass gets wiped off the planet.
Here's another term: Ecophile. One who loves nature but in a self-centered, delusional, destructive, and exploitive fashion. As in Pedophile.
Anyway, excuse me while I attempt to go sweat out the rest of this fever. . .
Oh, and lastly, so since I've been asked a great deal lately--how long will it take to get a homestead together in the manner in which you have? Two years. If you have help. I'm not there yet either, but certainly striking distance and have may a few, but not to many mistakes. I don't mind being a pioneer. Someone needs to.