Acres Needed to Support a Family

Looking to the future, and a time when we will have to support ourselves, again, largely by agriculture-without-oil, I thought I’d look into this subject. Let me start with some U.S. Department of Agriculture data (link, see tables at the bottom of that page). These show historical farm acreage under cultivation. From these I’ve calculated “big picture” averages, thus how many acres supported a person in the past, do so now, and that number, multiplied by 4, provides some idea of what a family needs for support. Here is the tabulation:

Farm acreage per person and family of four
	Farm	U.S.	Acres	Acres
	Land	Population	per	per
Year	(000 acres)	(million)	person	4 People
1850	293,561	23.2	12.7	50.6
1860	407,213	31.4	13.0	51.8
1870	407,735	39.8	10.2	41.0
1880	536,082	50.2	10.7	42.7
1890	623,219	62.9	9.9	39.6
1900	838,592	75.2	11.1	44.6
1910	878,798	92.2	9.5	38.1
1920	955,884	106.0	9.0	36.1
1930	986,771	122.8	8.0	32.1
1940	1,060,852	132.2	8.0	32.1
2010	918,840	308.7	3.0	11.9

An interesting table. Notice that, with a population nearly three times greater than we had in 1920, we used fewer acres of farmland in 2010. Note that the number of acres needed to support a person declines as time passes, from a max of 13 in 1860 to a mere 3 acres in 2010. Similarly the acreage to support a family has shrunk by more than a factor of four between 1850 and 2010. What explains this? Fossil fuels—for doing the mechanical work, for increasing fertility, for controlling pests, for freezing, processing, and transportation.

In turn, the disappearance of such fuels means that, out in time, the need for acreage will either greatly increase or the population will have to shrink. Supposing that we needed 10.2 acres per person in 2010 (as we did in 1870). In that case we would’ve needed 3.1 billion acres under cultivation to support the population—nearly three times the maximum acreage (1.1 billion) we’ve ever cultivated in the United States (in 1940). Pondering that requirement will produce some interesting future scenarios. For starters, our current farm acreage includes some significant portion which requires fossil fuels to pump water to make it useful; such acreage will first fall away. How much naturally arable, rain-watered land do we have? I don’t know, but I’ll post something on that in the future.

Now for another kind of take on the subject, this time working from the bottom up, asking ourselves how many calories we need and what amount of acreage we might need to produce it. Here I’ve found a splendid article written by Nathan Lewis and published on a site called 24hgold.com (link). The article is long but well worth reading carefully if your thoughts are on the longer-term future. Lewis concludes that a family will need minimally 17 acres to sustain itself, operating organically, including having a horse. Now that just feeds the family. The farm does not, as yet, sell much of its product to others—just enough to buy the extras needed for survival. Interestingly, if the family had an 1850-level 50 acres, it would also be able to provide for two other families living in town and, say, sew clothes or shoe horses.

Difficulties loom ahead here, but this transition we will have to accomplish—and do it right. It will take all of our ingenuity, hard work, and dedication to get there—compared with which the making of a new hot version of a smart-phone will seem like the mere buzzing of a fly.

Japanese and U.S. Agriculture

In writing yesterday’s post, I discovered, to my surprise, that Japan employs more people in its agricultural sector (2.3 million) than we do (2.2 million)! This then made me look up data on agricultural land in each country. Japan farms 11.5 million acres; we farm 922 million. Thus every Japanese farmer (on average, of course), tends 4.8 acres; every American farmer tends 418. Velly interesting! Further thought about this began to yield some reasons for this startling difference. The first thing that comes to mind is crop. Japanese agriculture is focused on rice—a kind of farming that does not lend itself to automation; our own enormous productivity is due to machines and chemicals applied to grains that grow on dry land. The second is that Japan is second to no one in the fierce protection it gives its agricultural sector.  So I thought I’d look into automation of rice production—and came up with a video (link). It shows the prototype of a robotic rice planting machine—the one that won Japan’s “The Robot Award 2008” Grand Prize. 2008? That’s just yesterday. And we learn that it still has problems. Commercial models are promised us within a decade. Why is automation beginning so late? Well, evidently the farming population in Japan is old, as in years, and the young are disinclined to follow their grandmas and grandpas into the paddy. So Japan is rolling up its sleeves…

The Vanishing Farmer

A fascinating report from the Bureau of Labor Statistics, issued about a year ago, shows data on agricultural (and other sectoral) employment for a 40 year period by leading industrial countries (link). I came across the report in trying to get at reasonably current and accurate estimates of employment in Agriculture.  Here is a graphic that provides a look at this sector:

What we see here is the gradual disappearance of the farmer across a selection of countries from the industrialized world. I’ve charted data from 1973 (rather than 1970), because values were missing for some of the countries in the first year of this series. Food is basic to humanity, yet in the technologically advanced societies represented in this sample, only 2.6 percent of total employment was required for its growth for the group in 2010, a significant decline from 1973 when the average was 8.7 percent.

In 2010 the United States employed 2.2 million people in farming, down from 3.6 million in 1973. It surprised me to discover that Japan employed more people in farming in 2010 (2.4 million) than we did; it also employed more in that sector in 1973 (6.8 million).  The lowest percentages belong to the United Kingdom—the first of the industrialized countries.

Now what we’re really seeing here is actually the massive deployment of fuels, chemicals, machinery, and automation to the basic industry of humanity. I put fuels first because all else depends on them. Everything today is stamped by the great mark of the Age of Fossil Fuels. And as these disappear  by this century’s end, a reversal of these trends is certain.

Yes. The same trends are visible also in the other categories covered by this report. Employment as a percent of total has also declined in Industry and Manufacturing as a part of that. All the gains in these countries have been in Services. And unemployment has increased in each.

The paradox is that “the end” is still too far away, hence the loud voices are shouting Growth, Growth, Growth. No one minds the barely heard voices crying in the wilderness: Prepare, Prepare, Prepare. The Great Transition is too far away. Our timid leaders find it far easier to hold up tin gods for us worship—human ingenuity that will (deus ex machina, literally) save us before it is too late.

When We Eat, We’re Eating Energy

Herewith some startling numbers. A report by the Congressional Research Service in 2004 (link), provides direct and indirect energy consumed in Agriculture, including crop and livestock production. The numbers are in quadrillion BTUs, and the answer is that we consumed 1.7 quadrillion BTUs of energy, 1.1 quadrillion BTU in direct uses, and 0.6 quads in indirect, thus for fertilizers and pesticides. A USDA Factbook (link) tells us that “The aggregate food supply in 2000 provided 3,800 calories per person per day.” The (late) 2012 Statistical Abstract (link, Table 2) tells me that the 2002 population of the United States was 288.1 million people. So let us combine these numbers. Below the CRS data shown graphically:

Now one food calorie, also known as a kilo calorie, is worth 3.968320721 BTUs. Put another way, it takes 0.251995761 calories to make a BTU. So we can convert calories to BTUs or BTUs to calories. A quadrillion is 10¹⁵. Here is what it looks like: 1,000,000,000,000,000. So let us proceed.

If we apply year 2000 calories per capita to the 2002 population, we discover that in that year agriculture provided 1.1 trillion calories per day or 399.6 trillion calories a year to the total population. We can render that number into BTU-equivalents by either multiplying by 3.968… or by dividing it by 0.25199…. In any case we will be 1.584 quadrillion BTUs. That was the energy output of our agriculture in 2002 measured in quads of BTUs. So what did we expend in energy to get that output? What was the energy input? It was 1.7 quadrillions of BTU.

To get a ratio here, we take the input and divide it by the output. The result is 1.072. In other words, we expended more calories in industrial energy to get 1 calorie that we could eat. But the energy ratio calculation is not yet done.

We learn from this story in the Atlanta Journal Constitution, by William G. Mosely, co-author of a 2010 National Academy of Science study, “Understanding the Changing Planet: Strategic Directions for the Geographical Sciences,” that in addition to direct and indirect energy uses, an equivalent amount is used in processing and packaging of food. These two are, according to Mosely, 7 percent each of national energy use. And then another 3 percent of national energy consumption is used in food distribution.

Using these additional inputs, it turns out that in 2002 we used total energy of 4.13 quads as input for that 1.58 quads of caloric output. The cost now turns out to be 2.6 units of energy in for each unit of edible energy out.

Therefore it is absolutely true that we are eating energy in this modern day and age. This should make us very alert when we think about World Population. It has now reaching 7 billion—projected to reach 8 billion in 2050—a time by which we shall have pretty much consumed currently know hard reserves and only shale stuff will be left to take us to the next billion-person addition to the human family.

Added later. Thanks to russel’s comment to an earlier version of this post, I realized that I was using the wrong kinds of calories, not the kilo calories used in food. This post has therefore been updated to correct that very big error. I appreciate the correction.