Food in Winter: Eating Locally Means Preserving Locally

Food prices have been rising; between June and November 2010 the prices of staples such as wheat and corn have gone up by more than 25% (1). One likely reason is rising energy costs. Food production is energy-intensive, and if the cost of energy rises, so must the price of food. In the U.S., we consume over 10 quadrillion Btu (quads) of energy a year, about 10% of our total energy consumption, to produce the food we eat. Some of this energy is used to manufacture fertilizer and pesticides and to run farm equipment. Much of the energy is used to transport, process, package, distribute, and market food items. But the biggest chunk of energy used by the food system is for storing and cooking and otherwise preparing food, most of which happens in the home (2).

It’s looking increasingly likely that global oil production has peaked; even some previously skeptical commentators have come to this conclusion (3). If production has peaked, global oil supplies will eventually start to decline. It is not clear whether this decline will be steep or gradual or how soon it will begin. If the decline is steep, the price of liquid fuels such as gasoline and diesel could rise rapidly, and there could be shortages. The food system, with its many interconnected links dependent on liquid fuels, is vulnerable, and this means food itself could become more expensive or even scarce.

One solution, for areas with suitable land and enough rain, is backyard food production and local agriculture. Locally grown foods, less dependent on transportation and distribution networks, should be somewhat immune from the worst effects of price increases and possible shortages of fuels (4). But local food production cannot be depended upon if the supply ends when the growing season ends. Even with hoop houses and other technology to extend the harvest, in most of the U.S. locally grown food will not be available for half the year unless it’s been preserved. If shipments from California, Florida, and Mexico become expensive or unavailable, there better be something in the refrigerator, the freezer, the cold cellar, the smokehouse, the pickle barrel, or the pantry.

There are many tried-and-true methods of food preservation. An important aspect is energy use. Using estimates in the literature (5) and my own calculations I have estimated the energy consumption of a variety of these methods. Freezing and refrigeration score especially poorly, in part because electricity must include the energy required to produce it, and also because a freezer must run for an entire storage period whether it is full of food or down to one item. Drying requires a lot of energy. But once dried, foods will keep for many years if properly stored. Canning requires energy too but canned vegetables and fruits will keep well for several years. And some canned foods such as tomato sauce (pictured above), if made from home-grown, vine-ripened fruit by someone with anything like the skill of my wife Louise, are better than what you can buy.

Local food-growing systems will become more meaningful and important to the degree that they address the importance of food preservation.

(1) Foley, John, Food Prices Face a Perilous Rise, NY Times, 12/29/10
(2) CSS, 2007, Factsheets: U.S. Food System, http://css.snre.umich.edu/css_doc/CSS01-06.pdf
(3) See Krugman, Paul., The Finite World, NY Times, 12/26/10
(4) I am referring here to field-grown crops, not the extremely energy-intensive food production of heated greenhouses.
(5) Smil, Vaclav, 1991, General Energetics, John Wiley & Sons, NY

Lawns, the Price of Eggs, and Chicken Tractors

Lawns provide fine venues for sports, but why do people maintain big lawns that are never used for anything? Maybe lawns stimulate something deep in our psyches. Maybe at an unconscious level the smell of fresh cut grass equals “good” (food for a horse) or an expanse of close-cropped green surrounding the house equals “safety” (no snakes nearby). Lawns don’t come without some cost however. According to EPA, Americans burn 800 million gallons of gasoline yearly, about 0.6% of the total use of that fuel, to mow grass. Lawn care also uses water and pesticides.

A big lawn could become a useful resource for feeding chickens. There's an upsurge in interest in chicken-raising, perhaps related to the price of eggs, which has risen recently as shown in the chart. Agricultural commodities can be expected to rise in cost as energy prices increase, so eggs may get more expensive. Also, the grossly crowded conditions of today's industrial poultry operations raise questions about the quality of commercial eggs. Unfortunately, producing one’s own eggs with a small flock of chickens is only marginally cost-effective. The main cost is the price of feed. My calculations suggest that buying, housing, and feeding a dozen or so egg-laying hens for three years will cost in the range of $150 per bird, not counting the labor to take care of them. Each hen will produce approximately 50 dozen eggs during this period; so if the eggs are worth $3 a dozen the benefits more or less equal the costs.

However, if you have a flock small enough so that you can feed it largely with kitchen and table scraps, and if you can keep your chickens on good pasture a lot of the time, the cost picture improves. The scraps from a family of four could make up half the feed of four chickens. Good pasture would cut the feed bill further. Chickens will eat just about any food scrap that is at all edible. They are adept at catching flies and other insects and ticks. They love green matter so much that they will quickly defoliate a small fenced-in yard, reducing its pasture value to virtually nothing. The key to providing good pasture is to have a large enough area so that the birds can’t get ahead of plant growth. An ideal approach is to frequently move them to fresh pasture. It’s not hard to do this with a different kind of lawn tractor - a chicken tractor. The chicken tractor pictured was built by a co-worker of mine, Dave Bean. It houses several chickens and is not hard to move around on the lawn. It protects the chickens from predators, but it’s open to the grass below. With a chicken tractor making its rounds, the chickens eat, the grass gets chopped off and fertilized, lawn insects and ticks are obliterated, and there’s still a lawn area for a volleyball game.

Doctober

One of the beautiful and useful aspects of sports is that they teach us something about “the zone” – that place where we concentrate, think piercingly, aren’t so conscious of time, do better. Roy “Doc” Halladay, the Phillies pitcher who tonight entered the history books by throwing a no-hitter in the post-season opener, was clearly in the zone. His teammates, including the shrewd catcher Carlos Ruiz, were likely there too. Shane Victorino, the Phillies centerfielder, who got a key hit in the game, was surely in the zone. Asked by a Phillies sportscaster after the game when it occurred to him that Halladay was on his way to a no-hitter, Victorino replied that he really hadn’t thought about it. He was concentrating on the game, staying loose, ready. He added that it wasn’t until he realized Halladay had two strikes on the last batter in the ninth that he knew something special was in the making. The same question – when did you think you were on the verge of making history - was posed to Halladay himself. He seemed a little surprised. “After the game,” he said.

When athletes are talking about what they’re thinking or feeling when they’re out on the field, it’s worth listening. They can tell us about being in the zone. On this day, the start of the playoff season, now perhaps lastingly dubbed “Doctober” by Phillies fans in honor of Halladay, Shane Victorino and Roy Halladay have told us something about this heightened level of consciousness: when you’re in the game and in the zone, you’re in the game, and that’s all there is.

Still in Service - Why?

My 1985 GMC S15 pickup is still in service. Why? Economics seems reason enough to a penny-pincher like me, but there’s more to it.

The economics are simple. Long since paid for, this truck’s costs are essentially limited to fuel and repairs. There’s no need for more than liability insurance. Repairs don’t amount to much; it’s only driven 3,000 miles per year, and I have a good friend who’s an expert mechanic. Junkyards are full of parts. Payments on a newer truck might be $300 a month or more. If you divide that by the number of times a month I start it up, maybe 15 times, it’s as if the old truck spits out a $20 bill every time I turn the key.

A bigger issue though is the environmental and safety impact of a vehicle. This truck emits about three times the carbon monoxide, nitrogen oxides, and hydrocarbons per mile as a new truck would. But in most parts of the country, the air is cleaner these days. Driven as little as it is, the contributions of this truck to the dwindling air pollution problem seem relatively trivial. The safety issue is more problematic; this truck has no air bags, no anti-lock brakes. Yet, since it’s mostly driven locally and during the daytime in good weather, I estimate my chances of staying alive with it aren’t too much worse than they’d be with a new truck. Neither of these impacts seems to rise to the level of truly important to me.

Evidence is building, however, that there’s an environmental problem that’s far bigger than emission of conventional air pollutants. This is climate change, which is clearly driven by greenhouse gases emitted by human activities. The best reason to keep an old vehicle on the road may well be its fuel-efficiency compared to a newer vehicle, since burning gasoline emits carbon dioxide, the major greenhouse gas.

The energy tally for motor vehicles has two main components; the energy used in producing a new vehicle, and the energy used in driving it.

It takes about 80 gigajoules of energy to produce a light-duty motor vehicle, including mining and producing the metals and other materials, assembly, and end-of-life recycling.[1] This is a vehicle’s “embedded energy.” It translates to approximately 5 metric tons of carbon dioxide emissions. Once on the road, combustion of a gallon of gasoline releases about 8.9 kg carbon dioxide. At 25 miles per gallon, driving 12,000 miles therefore releases over 4 metric tons of carbon dioxide. So, over a ten year lifetime, the carbon dioxide emitted by driving far outweighs that emitted from producing a vehicle. Keeping a vehicle longer improves the ratio of embedded to operating energy still more. For most drivers then, it makes sense from a greenhouse gas perspective to junk an old vehicle in favor of a new one if the new one is significantly more fuel-efficient.

But that’s a problem, because there aren’t more fuel-efficient trucks available in the U.S. market! This truck was designed in the 70s when the nation cared a lot about fuel economy. It is small and simple. It has no power steering, no power brakes, no power windows. It gets 28 mpg on the highway. Amazingly, even if I wanted to, I couldn’t buy a new truck that gets better mileage than this truck. Most new trucks have far worse mpg. So until more fuel-efficient trucks are on the market, or until some truly major repair is needed, I’ll continue to drive the most beat-looking truck in the parking lot. And I’ll continue to enjoy its major side-benefit of, in effect, sliding a $20 bill into my wallet every time I start it up.

[1] Stodolsky, F., A. Vyas, R. Cuenca, and L. Gaines, 1995, Life-Cycle Energy Savings Potential from Aluminum-Intensive Vehicles, Argonne National Laboratory, Argonne, IL 60439

Weeding Out False Positives

Weeds are unwelcome parasites in a garden, taking water, nutrients and light away from plants we want to grow. Individually or in low numbers, they aren’t a concern, but a weed infestation can be devastating. A false positive is a belief that things are connected when in reality they are not. In a way, a false positive is a weed of the mind. Like weeds, false positives seem to sprout naturally. We look for patterns and connections, and we file away memories of what look like cause and effect relationships. False positives are typically harmless, but if there are enough of them, or they are particularly influential, they can lead us astray. In his recent book The Vanishing Face of Gaia, James Lovelock points out that superstition and belief in magic – classic examples of false positives - are long-standing habits of human thought, whereas the scientific method, with its use of observation and measurement to circumvent false positives, is only a few hundred years old.

I had a chance to weed out a false positive three months ago. A person who seemed authoritative told me that it was getting time to plant peas, but that the Farmer’s Almanac said that peas planted on March 21 would rot in the ground. My plan had been to plant peas on just that day, and my first thought was to put it off to another day with a less ominous prediction. After all, it’s a strange world, and maybe the Almanac had some insight on peas and planting dates. But March 21 was a beautiful sunny day, and the seeds went in the ground, albeit with some trepidation on my part. I’m happy to say they sprouted and have produced the bountiful plants in the photo above. Did I tempt fate and get lucky? I don’t think so. More likely, I just stumbled on another pesky false positive and, this time anyway, was able to pull it out.

The Hope of Trees Part II: Growth Boom

This tulip poplar, Liriodendron tulipifera, growing in central New Jersey, is big for its age. According to a guide for estimating ages of trees based on diameter, it is about 40 years old. But it’s only 23. I know because I planted it as a one-year-old seedling in 1988. Other more extensive evidence indicates that trees are growing faster than they used to. A recent study (McMahon, et al., 2010, Evidence for a recent increase in forest growth, PNAS, http://www.pnas.org/content/early/2010/02/02/0912376107.abstract) measured growth of trees in temperate forest plots in the eastern U.S. and found that the trees are adding biomass at a rate much higher than formerly. The article references a number of other studies with similar findings. A higher growth rate for trees is consistent with data, pictured in the chart below from James Hansen’s recent book, Storms of My Grandchildren (p. 119), showing that, despite large increases in anthropogenic carbon emissions since 1950, the fraction of emitted carbon that ends up in the atmosphere has remained at about 50%. The rest of the emitted carbon, now totaling about five gigatons each year, is absorbed in approximately equal portions by oceans and terrestrial plants (Watson, et al., 2009, Tracking the variable North Atlantic sink for atmospheric CO2, Science, 326, 1391-1391).

This means that despite widespread deforestation, the world’s forests and other plants are taking up more than twice as much carbon today than they did in 1950. How is this happening? McMahon et al. suggest that the higher growth rate is driven by fertilization from increased CO2 in the atmosphere, warmer temperatures, a longer growing season, or a combination of some or all of these. More research is needed, but it seems likely much of the increase is due to CO2. It is food for plants. For millions of years, plants have been accustomed to levels of CO2 in the range of 225 to 280 ppm. Its atmospheric concentration today is nearly 400 ppm. As long as their growth is not limited by something else, plants could be expected to grow much faster in today’s CO2-rich world.

Among the concerns about climate change, the booming growth of trees is a ray of hope. It's becoming clear that lowering emissions and halting the growth of CO2 in the atmosphere won't be enough to avert dangerous climate change; the CO2 concentration must be reduced, probably to the vicinity of 350 ppm. Trees and other plants can help do this by eating up atmospheric CO2, and their capacity to do this seems to be accelerating.

The Hope of Trees Part I: Biochar

This looks like coal but it’s different in a key way. It’s charcoal, also called char, or biochar, and like coal is mostly carbon. Unlike coal, which is carbon sequestered 300 million years ago, biochar is carbon recently pulled from the atmosphere by trees. Buried in the ground it will foster plant growth and likely remain as is for many hundreds of years. Biochar is produced by combusting wood with limited oxygen. Done in a controlled way, emissions are minimal and energy is a byproduct. The Earth’s forests accumulate about 60 gigatons (Gt) of carbon per year, but they give almost all of it back to the atmosphere on a short time scale as leaves and wood decay. Biochar is virtually immune to microbial attack and so if some of the carbon captured by plants can be siphoned off into the form of biochar, it will stay out of the air.

If produced and buried on a large scale, biochar could significantly lower the carbon dioxide content of the atmosphere. James Lovelock, in his book, The Vanishing Face of Gaia, (p. 151) says that massive production and burial of biochar, which would also produce, not consume, energy is “the only realistic proposal by which we have even a chance of restoring the Earth to the state it was in before we started using fossil fuel.”

The key question is whether biochar production could be scaled up to a dimension of planetary significance. Some are skeptical. Stuart Staniford, in his blog Early Warning, (http://earlywarn.blogspot.com/2010/03/scalability-of-biochar.html)
argues that only a few gigatons of carbon could reasonably be sequestered each year in the form of biochar, and this would not be a panacea for even the current level of 8.5 gigatons of fossil fuel emissions. Johannes Lehmann, in his 2007 article in Nature (vol. 447, pp. 143-144) provides some numbers that are more optimistic. He points out that in the U.S., the carbon in forest residues and crop residues amounts to about 0.5 Gt/y, and if currently idle farmland was converted to high production woody plants, another 0.25 Gt/y carbon could be harvested. This is for the U.S. only, which accounts for a relatively small portion of global biomass production.

It is possible that not only crop and forestry residues and production from marginal lands, but also production from some of the massive acreage that’s currently devoted to feed grains or corn for high fructose corn syrup could be converted to biochar production. And fossil fuel emissions could be cut by major conversion to nuclear power. Then, biochar could cancel out much of humanity’s fossil fuel emission, or even go beyond that and start to bring down the carbon content of the atmosphere, while at the same time producing useful energy. On paper, this seems do-able with existing technology, and that’s reason enough to take a closer look.

Electric Cars and Coal

Full battery electric vehicles are claimed to reduce greenhouse gas emissions by 50% to 75% compared with conventional gasoline-powered cars. As discussed below, a realistic percentage reduction is probably considerably less. And there’s a major problem with electric cars. Their large-scale adoption could ensure that the current generation of carbon-intensive coal-burning power plants continues to operate far into the future. An excellent case can be made that coal combustion must be phased out to avoid dangerous climate change. (See, for example, the book Storms of My Grandchildren, by James Hansen.) This phase-out is unlikely to happen if the industrial world tries to power its transportation system with electricity.

Electric motors seem ideal for vehicles because they are highly efficient – they turn about 90% of supplied energy into motion. But powering them from batteries offsets some of this efficiency. Batteries aren’t so efficient. Energy is lost when they supply power, and it is lost when they are charged. Assuming an overall charge/discharge efficiency for batteries of about 65% seems reasonable. Production of electric power is less efficient still; the national average is about 35%. The net efficiency of the power system of a fully-electric car is thus about 0.9 x 0.65 x 0.35, or 20%. This is no different than a gasoline engine. Can these efficiencies be improved? Certainly. But it's hard to see how electric car power system overall efficiency could get much better than 30% as long as the power to charge the batteries comes from the relatively inefficient electricity production system.

Electric cars' greenhouse gas emission reduction potential depends to a large degree on the carbon intensity of this system. Overall, U.S. electricity production releases about 1.3 pounds of carbon dioxide per kWh. This is about 25% less carbon dioxide than if the electric power was produced by a fuel with the carbon content of gasoline. In some parts of the country such as New Jersey, which has a lot of almost carbon dioxide-free nuclear power, this rate is lower, and electric cars reduction potential is somewhat larger.

If the U.S. could produce more electricity from renewable and nuclear sources, and from efficient combined heat and power plants, electric cars would look better from a greenhouse gas perspective. But how likely is a major shift in the generation mix any time soon? It seems more likely that increasing numbers of electric vehicles will provide the excuse for electricity producers to keep old coal-burning plants going.

What to do? We could take a fresh look at diesel engines, which are more efficient than gasoline and comparable to even optimistic estimates for full battery electric when the entire power cycle is considered. Diesels can run on low-carbon fuels like natural gas. We could significantly downsize our cars. This would produce major gains in miles per gallon. And we could get serious about making telecommuting work. It's worth looking seriously at the greenhouse gas reduction potential of such changes before we spend huge amounts of money converting our transportation system to full battery electric.

Climate Change Contrarian Nonsense

There's been a recent spate of contrarian nonsense regarding climate change. There's no better evidence that the earth is warming than the relentless rise of the seas everywhere. Recent data show that the rate of sea level rise is accelerating. (See chart in McCarthy, James, 2009, Reflections on: Our planet and its life, origins, and futures, Science 326, 1646-1655, reproduced here)

The ocean is rising for two reasons only; melting of glaciers and thermal expansion. It takes added heat to do this - a lot of it. If we humans don't get serious about dealing with this problem, fifty years from now, as floods hammer unprepared coastal cities, folks who egregiously misinformed people will deserve some of the blame. Several books that cut through the confusion are Storms of My Grandchildren by James Hansen, The Long Thaw, by David Archer, and The Rising Sea, by Orrin Pilkey and Rob Young.

Productivity and Energy Cost

This chart shows GDP per hour of work by U.S. workers. It also shows U.S. expenditures for fuels as a percent of gross domestic product. GDP per hour of work is a measure of productivity. Note that throughout the 50s and 60s, productivity increased steadily. There were some actual decreases in productivity in the 70s. It grew again, at what looks like an exponential rate, from about 1995 to 2005. Following this period of accelerating increase, a lull in productivity growth began in 2005. Note that this downturn began well before most economists were talking of recession.

It appears that periods of stagnant or decreasing productivity coincide with times of escalating energy costs. And it looks as if periods of steady growth in productivity correspond to times when energy costs have been relatively low, in the range of 3.5 percent of GDP or less. Such a correlation makes sense, because virtually every economic activity in the industrialized world depends on a supply of extraneous energy, mostly fossil fuel. It’s been said that the economy today is less energy-intensive than it once was, and so is less vulnerable to increases in the cost of energy. It’s indeed true that we produce more goods and services today per unit of energy than formerly. That doesn’t make the economy less energy-dependent. The industrial economy was nearly 100% dependent on extraneous energy in the 70s and 80s, and it is nearly 100% dependent on such energy today. Arguing that a less energy-intensive economy is less vulnerable to increasing energy costs is like arguing that a person who drives a car that gets 40 mpg is less dependent on gasoline than a person who drives a car that gets 20 mpg. Both drivers are 100% dependent on gasoline if they want to drive, and if fuel costs go up too much, the product of their driving - miles traveled - will go down.