Saturday, June 30, 2007

UK Food System Energy Use

At the 8th ECEEE conference (June 4-7 2007), Rebecca White of the Environmental Change Insitute presented a paper entitled "Carbon governance from a systems perspective: an investigation of food production and consumption in the UK". The paper discusses the amount of energy used in UK's food system, and the percentage of total UK energy use, 10.8%, is very similar to the amount of energy found to be used in the U.S. food system as I discussed earlier. In the U.S. research shows that between 10-17% of U.S. total energy consumption is in the food system.

From White's report comes this graphic and quote:
"Table 1 shows a sectoral break down of energy use across the UK’s food system... As it stands, this equates to 10.8 % of the UK’s delivered energy consumption, excluding the air freight contribution. Further omissions include: energy used in fishing, in the production of plastic packaging and the off-farm storage of fresh fruit and vegetables, often imported, that can be stored and ripened in temperature controlled environments for considerable periods. Food related waste management has also been excluded. There is also some uncertainty around the numbers, in particular the amount of energy used to store food. Because storage occurs at a number of different points in the food chain, it is often not clear how this is allocated sector-wise. There are also very varying estimates of energy use in the retail sector. The figure used here is taken from the Food Industry Sustainability Strategy (DEFRA 2006), however an estimate from the DEFRA food miles report, published a year earlier, gives an estimate of 97.9 PJ. This alters the percentage of total UK energy use that food is responsible for to 11.8 % and increases the fossil carbon impact from 19.2 MtC to 22.9 MtC. With all figures presented in Table 1 only direct energy use on site and in the production of inputs has been included rather than any embodied energy in machinery or vehicles, which is usually included in food life cycle analyses (LCA)."

Source: Rebecca White, " Carbon governance from a systems perspective: an investigation of food production and consumption in the UK", Environmental Change Institute, Oxford University Centre for the Environment, June 2007,

UK Carbon Labelling

The UK is moving forward fast on understanding the amount of energy and carbon in their national food system. The main organizations moving forward on this are the Carbon Trust, The UK Energy Research Center (UKERC), and the Environmental Change Insitute at the Oxford University Centre for the Environment (ECI).

On May 18, 2007, various government, NGO, and private sector organizations met in London to discuss how carbon labelling of products should occur. The ECI weblink contains various documents pertaining to this symposium. This idea, one I have been discussing ever since first seeing the Carbon Trust label work, is gathering energy (pun intended) especially with the announcement by UK supermarket giant Tesco "to develop a carbon footprint labelling measure for all products sold in store, and cut the cost of many energy-efficient goods." Orion magazine reported that Tesco will spend £5 million to research methods for calculating the carbon content of retail goods.

on May 3, 2007, was an earlier Carbon Labelling Roundtable that began the discussions around what a carbon label would actually entail. A lot of work needs to be done to fully understand what is to be measured, the relationships between various segments and sectors of the food industry, and what incentives are needed to encourage low carbon foods.

One thing I want to highlight deals with this basic question: where do we start?

Various report comments touch on the idea of "Just do it" and to start moving on what we do know as we develop what we don't know. Considerations were also made as to "Which products first?". From the May 3rd Rountable report (1) :

" The participants put forward various possible criteria which would help determine which products to begin carbon profiling. The participants identified their priorities and the results are ranked below - those in bold were most strongly supported:
  • components of a standard shopping basket (as for the retail price index) (this implies that a standard shopping basket of particular goods could be introduced as a way of comparing the carbon footprint of retailers)
  • products where data available
  • biggest potential for carbon saving
  • where there is supply chain interest / enthusiasm
  • simplest to measure
  • where greatest GHG variation within category
  • organic products
  • entire categories rather than products
  • highest sales volume
  • where consumers most likely to switch
  • low food mile products
  • non-food vs food
  • non-contentious
  • most carbon intensive
The report of this meeting to the May 18 roundtable added "Driven by procurement" as another priority area.

Source: (1) Brenda Boardman, "Carbon Labelling: report on roundtable 3rd-4th May 2007, St Anne’s College, University of Oxford", UKERC/ECI

Sunday, June 10, 2007

Vitamins and Their Food Sources

So what foods are the best source for vitamins? The Seattle Times recently ran an AP article "An A-Z guide to vitamins", that lays out what different vitamins do and where to get them from food.

To note: "Americans spent $2.3 billion last year (2006) on vitamins and nutritional supplements." (1)

The main vitamin table is a pdf file that can be downloaded of viewed by clicking here. Let me know if the link goes dead.

So, how does this compare to the previous post about healthiest foods? Hmm ...

Source: (1) Hillary Rhodes (Associated Press), "An A-Z guide to vitamins", Seattle Times, Sunday June 10, 2007

Saturday, June 9, 2007

Esimating Size of Food Servings

The USDA's Nutrient Data Laboratory has created a table call Tips for Estimating Amount of Food Consumed in their publication "Nutritive Value of Foods"

" This table lists some handy tips to help you estimate the amount of food you eat when you cannot measure or weigh it."

Here is the table data:

Breads and grains
1⁄2 cup cooked cereal, pasta, rice: volume of cupcake wrapper or half a baseball
4-oz bagel (large): diameter of a compact disc (CD) medium piece of cornbread medium bar of soap

Fruits and vegetables
medium apple, orange, peach: tennis ball
1⁄4 cup dried fruit: golf ball or scant handful for average adult
1⁄2 cup fruit or vegetable: half a baseball
1 cup broccoli: light bulb
medium potato: computer mouse
1 cup raw leafy greens: baseball or fist of average adult
1⁄2 cup: 6 asparagus spears, 7 or 8 baby carrots or carrot sticks, or a medium ear of corn

Meat, fish, and poultry, cooked
1 oz: about 3 tbsp meat or poultry
2 oz: small chicken drumstick or thigh
3 oz: average deck of cards, palm of average adult’s hand, half of a whole, small chicken breast, medium pork chop

1 oz hard cheese: average person’s thumb, 2 dominoes, 4 dice

2 tbsp peanut butter: Ping-Pong ball
1⁄3 cup nuts: level handful for average adult
1⁄2 cup: half a baseball or base of computer mouse
1 cup: tennis ball or fist of average adult

Source: Susan E. Gebhardt and Robin G. Thomas, "Nutritive Value of Foods", USDA Agricultural Research Service, Home and Garden Bulletin, Number 72, rev. October 2002

Top 20 Healthiest Foods

So what are top 20 healthiest foods? I thought this would be easy research, but like most anything, the answer is: it depends. What are you measuring for: antioxidants? Vitamins? Proteins? By season? By cultural acceptance? These and other variables/parameters will control the outcome of any list making efforts.

However, there are some that appear on more lists than others.

I dove in by doing a Google search on "Top 20 healthiest foods". I selected lists from the first two Google hit pages, choosing what appeared to be the top 4 lists, alphabetized them, and then looked to see which foods appeared on the most lists. I am sure I have a subjective lens, so please chew on this and let me know if there are some additions or changes you may suggest.

Dried Beans (lentils, kidney, pinto, red, soy)
Fatty (oily) fish
Herbs, spices
Low fat dairy
Nuts and Seeds
Olive Oil
Whole grains, wheat (wheat germ, oat, whole wheat)

So what is the conclusion? A diet rich in simple, varied whole foods is the best thing for the body. This does not have to mean expensive. This searching came across a wonderful website called The Hillbilly Housewife shows with recipes and tips on convenient foods that are usually good buys.

Other sources for nutrition info for various foods:

Wednesday, June 6, 2007

More Energy in Food

Ken Meter, with the Crossroads Center in Minnesota, has compiled some wonderful facts regarding food markets. Here is one such fact:

" Annual cost of energy used in food system (production, processing and distribution), at current consumption rates (2005): $139 billion."

And here is how Ken figure this out, as noted in the footnotes:
"Calculated from ratio determined by FEA study cited above, using current Department of Energy data for energy consumption ($694 billion in 2001 -- DOE Table 1.5 Energy Consumption, Expenditures, and Emissions Indicators, 1949-2004,, viewed Nov. 27, 2005). Bureau of Labor Statistics data on consumer expenditures for food,, viewed February 7, 2006."

Source: Ken Meter, "U.S. Food Market Highlights", Crossroads Center, rev. Sept. 5, 2006,

Monday, June 4, 2007

Study: Farmers market food costs less

An article in the Seattle Times today discussed research done by a Seattle University economics class that compared the cost for farmer market food with nearby markets. The results go against the perception. From the article:
"The farmers market was slightly less expensive pound for pound, on average, for 15 items that included Fuji apples, red potatoes, baby carrots, spinach and salad mix."

Full article is available at the Seattle Times, entitled "Farmers-market food costs less, class finds".

Sunday, June 3, 2007

Nitrous Oxide in Ag, Part 2: Nitric Acid Production

I am trying to do a life cycle analysis of synthetic fertilizers and their impacts on climate change. I am having to do a rough analysis of production process and ingredients to start.

As previously discussed, Nitrous Oxide (N2O) is a major source of greenhouse gas emissions:
  • Nitrous Oxide (N2O) emissions from ag make up over 75% of the U.S.'s total N2O emissions.
  • N2O is found in ag primarily from fertilizer application and management of solid waste from animals.
  • N2O has 296 times more impact on the climate than CO2.

Let's add a defintion by the EPA: "Nitric acid (HNO3) is an inorganic compound used primarily to make synthetic commercial fertilizers. It is also a major component in the production of adipic acid⎯a feedstock for nylon⎯and explosives."(1)

So this shows pretty solidly that synthetic fertilizer production has a major impact on climate change.

A few questions come to mind:
  1. What are the source ingredients for Nitric Acid? Can we find a replacement for Nitric Acid and still grow enough food and materials?
  2. What is the power source for the industrial plants?
  3. What are the best substitutes and are there enough of them?
  4. Which crops receive the most? Which the least?
  5. What industrial processes have more impact on the climate?
To answer the last question first (since it is the easiest), we can turn to the EPA's U.S. Inventory Report chapter for Industrial Processes.

The top 10 Industrial Processes for Greenhouse Gas (GHG) emissions are listed below. The numbers represent teragrams (tg) of CO2 Eq, with 1Tg equal to 1 million metric ton (MMT CO2 Eq.)(2)

Top 10 GHG Emitting Industrial Processes (3)
  1. Substitution of Ozone Depleting Substances (123.3)
  2. Cement Manufacture (45.9)
  3. Iron and Steel Production (45.2)
  4. HCFC-22 Production (16.5)
  5. Ammonia Manufacture & Urea Application (16.3)
  6. Nitric Acid Production (15.7)
  7. Lime Manufacture (13.7)
  8. Electrical Transmission and Distribution (13.2)
  9. Limestone and Dolomite Use (7.4)
  10. Adipic Acid Production (6.0)
Major source ingredients for Nitric Acid production are:
  • Ammonia
  • Nitric oxide
And as we can see, ammonia manufacture is the #5 highest emitter.

EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks,1990-2003", :1990 – 2003, April 2005, p.161.
2) U.S. Energy Information Administration, "Emissions of Greenhouse Gases in the United States 2000", Appendix F (Common Conversion Factors), 2000
3) EPA, "U.S. Greenhouse Gas Inventory Reports", Chapter 4 "Industrial Processes", April 2007,

Nitrous Oxide in Ag, Part 1: EPA definitions

As discussed earlier:
  • Nitrous Oxide (N2O) emissions from ag make up over 75% of the U.S.'s total N2O emissions.
  • N2O is found in ag primarily from fertilizer application and management of solid waste from animals.
  • N2O has 296 times more impact on the climate than CO2.
So N2O has bad mojo on the climate, and the biggest source of U.S. emissions is from spreading fertilizers on the land.

As anyone who deals with government knows, a key issue is how terms are defined. So what is the definition used for ag lands as it pertains to this issue? The term used is "Agricultural Soil Management" (IPCC Source Category 4D), and the EPA defines this term this way: "Only direct emissions from agricultural lands (i.e., croplands and grasslands), along with emissions from PRP manure."
PRP is defined as "the deposition of manure on soils by animals on pasture, range, and paddock (PRP) (i.e., by animals whose manure is not managed)."

"Agricultural soils are responsible for the majority of U.S. N2O emissions. Estimated emissions from this source in 2003 were 253.5 Tg CO2 Eq. (818 Gg N2O)." (p. 19 in pdf)

So I want to know if this: do coventional ag practices have more or less N2O than organic or sustainable ag practices (e.g. low-till), and by how much?

As a starting point comes this quote from the EPA's Climate Change Inventory Report:
"Heavy utilization of synthetic nitrogen fertilizers in crop production typically results in significantly more N2O emissions from agricultural soils than that occurring from less intensive, low-tillage techniques."

But a few pages later in the report comes this:
"N2O emissions cannot be partitioned into the contribution of N2O from different N inputs (e.g., N2O emissions from synthetic fertilizer applications cannot be distinguished from those emissions resulting from manure applications). Therefore, it was not possible to separate out these individual contributors to N2O flux, as is suggested in the IPCC Guidelines." (pdf p.21)

To further refine the definitions, there are major crops and non-major crops.
  • Major cropping systems are "corn, soybean, wheat, alfalfa hay, other hay, sorghum, and cotton" and "represent approximately 90 percent of total cropped land in the United States."
  • Non-major crop types "include fruits, nuts, and vegetables, which account for approximately 5 percent of U.S. N fertilizer use (TFI 2000) and other crops not simulated by DAYCENT (barley, oats, tobacco, sugar cane, sugar beets, sunflower, millet, peanuts, etc.) which account for approximately 10 percent of total U.S. fertilizer use."

Source for quotes: EPA, "US Emissions Inventory 2005: Inventory of U.S. Greenhouse Gas Emissions and Sinks,1990-2003", Chapter 6 Agriculture, pp. 195-227.