Feedlot cows produce more methane than pasture cows

As more researchers work to understand where ghg emissions occur in ag practices, we can begin to parse growing practices to determine which have a lower carbon footprint.

Environmental Health Perspectives posted recent research, Global Farm Animal Production and Global Warming: Impacting and Mitigating Climate Change, that does some of this parsing by combining the results of various related studies.

Here are some emerging facts from that article:

1. "Animal agriculture sector accounts for approximately 9% of total CO2 emissions, which are primarily the result of fertilizer production for feed crops, on-farm energy expenditures, feed transport, animal product processing and transport, and land use changes (Steinfeld et al. 2006)."
2. "Burning fossil fuels to produce fertilizers for feed crops may emit 41 million metric tons of CO2 per year (Steinfeld et al. 2006)."
3. " Farm animals and animal production facilities cover one-third of the planet's land surface, using more than two-thirds of all available agricultural land including the land used to grow feed crops (Haan et al. 1997). "
4. "Typically, cattle confined in feedlots or in intensive confinement dairy operations are fed an unnatural diet of concentrated high-protein feed consisting of corn and soybeans. Although cattle may gain weight rapidly when fed this diet (Pollan 2002), it can cause a range of illnesses (Smith 1998). This diet may also lead to increased methane emissions."
5. And this: "The standard diet fed to beef cattle confined in feedlots contributes to manure with a "high methane producing capacity" (U.S. EPA 1998). In contrast, cattle raised on pasture, eating a more natural, low-energy diet composed of grasses and other forages, produce manure with about half of the potential to generate methane (U.S. EPA 1998)."
   

So feedlot cattle appear to produce twice the methane as pasture due to the diet. I assume this does not include the any methane from fertilizer or feed growing practices.

The first response seems obvious: eat less meat. The counterpoint is that we need protein. We can of course grow more pasture beef, but at current consumption habits we would have to expand land use for cattle quite significantly if we consume meat at current levels. Also, as health efforts (partially) succeed in getting us to reduce our red meat consumption in this country, as economic progress grows in developing nations, particularly China and India, meat consumption increases potentially negating any ghg reduction we have accomplished.

Ugh. So what can we do?

Since the climate is a global issue the pathway forward needs to incorporate global, national, and local concerns:

1. Reduce feedlot cattle consumption everywhere.
2. Increase the production of pasture beef.
   
1. Which also decentralizes manure production and reduces the necessity of using fossil fuels to create fertilizers, and then transport them to buyers.
   
3. Generate large consumer awareness programs in developing nations that as they turn their diets towards more red meat consumption that they request pasture beef.
1. Other research shows that pasture beef has more omega 3 fatty acids than feedlot beef (will get source).
   
4. Encourage trade policies that incentivize the production of low carbon meat.
   

Secondary source (primary sources in brackets, available in article): Koneswaran G and Nierenberg D, Global Farm Animal Production and Global Warming: Impacting and Mitigating Climate Change, Environmental Health Perspectives Volume 116, Number 5, May 2008, www.ehponline.org/docs/2008/11034/abstract.html

Shipping emisssions recalculated

The UK Guardian ran a story last week entitled "True scale of CO2 emissions from shipping revealed: Leaked UN report says pollution three times higher than previously thought". The story is based on a report leaked from the UN to the Guardian that "calculates that annual emissions from the world's merchant fleet have already reached 1.12bn tonnes of CO, or nearly 4.5% of all global emissions of the main greenhouse gas." This number, 1.12 bn tons, is almost three times higher than previous estimates of a maximum 400 tons.

The report also mentions these points:

• " CO₂emissions are set to rise by a further 30% by 2020."
• " Other pollutants from shipping are rising even faster than CO₂emissions. Sulphur and soot emissions, which give rise to lung cancers, acid rain and respiratory problems are expected to rise more than 30% over the next 12 years."
• " A recent peer-reviewed study of shipping emissions found world shipping led directly to 60,000 deaths a year."

Does this mean that ocean transport is not the preferred shipping method with regards to carbon footprint? Doubtful, but it may take some pressure off of the concerns around air shipments which the reports.

The best metric is still around volume or weight measurement. How much cargo is shipped that generates 1.12 billion tons of carbon for ships? How much cargo is shipped that generates the 325 million tons of airborn-shipping carbon?

Source: John Vidal, "True scale of CO2 emissions from shipping revealed, The Guardian, Wednesday February 13 2008, viewed online Feb. 20, 2008, http://www.guardian.co.uk/environment/2008/feb/13/climatechange.pollution

Ethanol and E Coli

New reports are emerging around a concern that the increase in ethanol production is fueling an increase in E. coli contamination. The connection is distiller's grain, a byproduct of ethanol production, that is becoming a cheap source of food for cattle.

As reported in the Des Moines Register on Jan 27, 2008: "Studies at two universities suggest that feeding cattle a byproduct of ethanol production known as distillers grains may increase levels of a deadly form of E. coli bacteria.

"Concerned about those findings, U.S. Department of Agriculture scientists have recently put 300 cattle on a diet of distillers grains and are testing them regularly for the bacteria. Results won't be known until later this year."1

The article continues to say that "Researchers at Kansas State University noticed the possible E. coli connection to distillers grains in 2005. A second study found a twofold increase in E. coli levels in cattle fed the product compared with those that ate only corn. Research at the University of Nebraska showed mixed results. Cattle fed a diet comprising 10 percent to 30 percent distillers grains actually had lower rates of E. coli than cattle on a diet of all corn. But cattle fed 40 percent to 50 percent distillers grains showed higher E. coli rates.

"That would suggest that there was something about these distillers grains diets that influenced the ability of these cattle to shed E. coli," said David Smith, one of the scientists who worked on the Nebraska research."2

Richard Raymond, the U.S. Department of Agriculture's undersecretary for food safety, was referenced as saying "the government had no intention of restricting the use of distillers grains even if the E. coli link is confirmed, and would instead leave it to the industry to decide how to address the issue. One possibility, he said, is to vaccinate cattle."3

This is an ironic twist to progressive policy solutions and shows that we are indeed in a new world needing new solutions for new problems. By increasing biofuels we are increasing the economics of 'factory farms'. "Closing the loop", or turning a waste in to a product, has meant that in ethanol production wet grain mash is being reused as a feed supply for cattle, thereby lowering the production costs of cattle and increasing the economic returns of Confined Animal Feeding Operations (CAFOs, a.k.a factory farms). As well, a wet grain is more energy efficient since you do not use additional energy to dry the grain after ethanol production, which means the net energy balance of corn based ethanol is better with wet distillers grain than dried grain.

As well, recent federal legislation encourages the expansion of ethanol production. This will mean an increase in distiller's grain. Will it mean an increase in E. coli as well?

Makes the stomach turn just thinking about it.

Sources:
1) Philip Brasher, "Scientists study possible link between ethanol byproduct and E. coli", Des Moines Register, January 27, 2008, http://www.desmoinesregister.com/apps/pbcs.dll/article?AID=/20080127/NEWS/801270330
2) Ibid.
3) A quote from same article, not exact quote from Raymond.

Food's enviro impact as great as transportation and housing

In May 2006 the European Commission released the results of research in to the Environmental Impact of Products (EIPRO). Using life cycle analysis and some input/output methods they concluded that products in three sectors had the greatest environmental impact: food and drink, private transport, and housing. The report did not rank these three but says that " together they are responsible for 70 to 80% of the environmental impact of consumption, and account for some 60% of consumption expenditure." Also from the report:

Food and drink cause 20 to 30% of the various environmental impacts of private consumption, and this increases to more than 50% for eutrophication. This includes the full food production and distribution chain ‘from farm to fork’. Within this consumption area, meat and meat products are the most important, followed by dairy products. Food and drink were covered by only some of the studies so the results for that area should be treated with more caution. However, the general conclusions can be taken with a reasonably high level of confidence.

The report continues to say that passenger transport has a total impact range of 15-35%, and housing (including furnishings and appliances) has a range of 20-35%.

The next step in this work is to study the environmental improvements of products (IMPRO). how to lessen the impact of meat and dairy is to be researched with initial results due late in 2007.

Source: "Environmental Impact of Products - Analysis of the life cycle environmental impact related to the final consumption of the EU-25", European Commission Joint Research Centre, May 2006, http://ec.europa.eu/environment/ipp/pdf/eipro_report.pdf

Potential GHG reduction for regionally-directed food purchasing

A team of University of Washington students and professor(s) recently released a comprehensive report on the local food system entitled the "Seattle Food System Enhancement Project". Within this work is their Greenhouse Gas Report that compares the ghg emissions of a local plate of food to a comparable global plate. The team used a life cycle assessment approach using the ISO 14040 definition. Their methods are an attempt to create "A benchmark for examining the greenhouse gas impact of cultivating and transporting specific items of food into the city of Seattle."

The foods compared, and their ghg emissions:

• Regional plate
• WA apple, asparagus, potato; Alaska wild salmon
  
• GHG emissions = 2,102 grams CO2e
  

• Global plate
• New Zealand apple, Peruvian asparagus, Idaho potato, Norway farmed salmon
• GHG emissions = 3,083 grams CO2e
  

Net savings for local plate: 981 grams CO2e

I decided to start playing with this number and try to calculate potential ghg reductions if this was applied to a segment of the whole state population for part of the year.

There are about 6.4 million people in WA state. The major assumptions for my calculations are that 20% of the population would eat a comparable plate of lower carbon food for half the year (182 days). These assumptions are further tied to carbon savings that are comparable with this plate of food. Why such variables? Well, the research is just not there to elaborate on this pressing issue. We absolutely have to do more of these calculations to understand where ghg reductions can occur, but in the meantime I am going to work with such estimates. I also understand that people are not going to eat this same meal for half the year, but I will assume that 20% of the people could eat a plate of food, or total food for the day, that has a comparable ghg savings.

From these parameters comes the notion that if 20% of WA state residents ate a similar plate of lower carbon food for half the year we could reduce our food carbon footprint by 228,534 Metric Tons CO2e per year (.23 MMT CO2e/yr).

Here is a screenshot of my spreadsheet (click for larger image):

These types of savings are no small potatoes. I am a member of the Agriculture Technical Working Group for WA State's Climate Advisory Team. A medium reduction goal is 0.1 to 1.0 MMTCO2e per year by 2020.

Items for further research:

1. What are the ghg reductions for other regional products?
2. What are the economic impacts of such a change in purchasing?
1. Local multiplier work shows a strong positive gain.
2. Impacts on this trade-dependent state less clear.

Source: " Seattle Food System Enhancement Project", Program on the Environment Certificate in Environmental Management Keystone Project, 2006-2007, p.79, http://courses.washington.edu/emksp06/SeattleFoodSystem/Index.shtml

Carbon footprint: vegan diet vs. Chevy Suburban

The paper Diet, Energy and Global Warming compares the carbon footprint of plant and animal-based first to each other, and then to the carbon footprint of a Toyota Prius and Camry Solara, and Chevy Suburban. From the paper:

Narrative description
" The greenhouse gas emissions of various diets varies by as much as the difference between owning an average sedan versus a Sport Utility Vehicle under typical driving conditions."

Scientific description
" While for personal transportation the average American uses 1.7 × 107 – 6.8 × 107 BTU yr−1 , for food the average American uses roughly 4 × 107 BTU yr−1 . Thus there exists an order of magnitude parity in fossil energy consumption between dietary and personal transportation choices." The key number here is the 1.7 and 4 comparison since the exponent is the same.

Source: Gidon Eshel and Pamela Martin, Diet, Energy and Global Warming, Earth Interactions, May 2005, http://geosci.uchicago.edu/~gidon/papers/nutri/nutri3.pdf

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, http://www.eci.ox.ac.uk/research/energy/downloads/eceee07/white.pdf

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

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, http://www.eia.doe.gov/emeu/mer/consump.html, viewed Nov. 27, 2005). Bureau of Labor Statistics data on consumer expenditures for food, ftp://ftp.bls.gov/pub/special.requests/ce/standard/2004/region.txt, viewed February 7, 2006."

Source: Ken Meter, "U.S. Food Market Highlights", Crossroads Center, rev. Sept. 5, 2006, http://www.crcworks.org/foodmarkets.pdf

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.

Sources:
1) 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, http://epa.gov/climatechange/emissions/usinventoryreport.html

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.

Brand Exposure to Climate Change

The UK's Carbon Trust took a look at company and brand exposure in a report aptly entitled Is your brand at risk from climate change? The report looked at various business sectors and analyzed different criteria, including brand value, direct and indirect operational exposure, and ability to differentiate products on the issue of climate change.

The report is not too surprising: brands are exposed to an increase in risk from climate change. What is surprising is that the food industry is more exposed than the oil and gas industry. The food and beverage sector has the second highest risk percentage, and the largest financial exposure.

The attached graphic is from the report and shows that while the total market value for food and beverages is £66.5 billion (English pounds), the sector has a risk exposure of 10% with a value of £6.6 billion. This financial exposure is higher than Airlines, Oil and Gas, Banking, Telecomunications, and Food Retail.

(Click on image for larger picture)
(FTSE refers to the FTSE All-Share Index, an index representing 98-99% of UK's financial market capitalization.)

Source: Carbon Trust, "Is your brand at risk from climate change?", March 2005, www.carbontrust.co.uk

Ag Energy Compared to Oil Production Per Day

As I work to translate how much energy we use to grow, make and move the food we eat I decided to correlate the energy to the amount of oil that OPEC and non-OPEC nations produced each day.

To do this I had to simplify some numbers and I did this mainly be equating all energy use to gasoline. I expect that some people would call this way to much simplification for a very complex set of variables. For many others, however, this can help make sense, bring home, and simplify this complexity. Also, gasoline has a middle of the road energy rating, with diesel having more British Thermal Units (Btu), and propane having less (see BPA's Conversion table), so it is arguably the best vehicle for this work (pun intended).

Using the percentages of energy use discussed in a previous posting about Energy Use in Food, I calculated the number of days of the world's daily oil production across each segment of the ag and food sector:

• Ag Production: 5.1 days of world oil production
• Transportation: 3.4 days
• Processing: 3.9 days
• Packaging: 1.7 days
• Food retail: 1.0 days
• Restaurants & catering: 1.7 days
• Home preparation & storage: 7.6 days

Here is a screenshot of the worksheet I used to make these calculations. Click on the image for a bigger version. If we just use OPEC's daily output there are almost twice the number of days for each segment.

Ag Emissions and GWP, part 2

I am trying to uncover more Global Warming Potential (GWP) impacts from our food system. Some segments of agriculture are already tracked by the EPA (discussed in Part 1 of this chain): enteric fermentation in domestic livestock, livestock manure management, rice cultivation, agricultural soil management, and field burning of agricultural residues. There are some gaps that need addressing, and would best be aligned with other research like Heller/Keoleian's report and the resulting breakdown of energy use by segment: ag production (EPA), transport, processing, packaging, food retail, restaurants, home refrigeration, and then waste disposal (but not in Heller report).

Let's start with what we know. The US DOE's Energy Information Administration's (EIA) Emissions of Greenhouse Gases in the United States 2005 report details Carbon Dioxide (CO2), Methane (CH4), and Nitrous Oxide (N2O) emissions as well as other GHG gases.

Methane
CH4 is produced as part of normal digestive processes in animals(1). It is also a byproduct of landfills and decomposition, and landfills have already been tapped for this energy source. The EIA methane report shows that from what we measured in 2005 for anthropogenic methane emissions we know:

• 
• Methane has a GWP rating of 23.
  
• Total U.S. Methane Emissions were 26.6 million metric tons
• 611.9 million metric tons CO2 equivalent (CO2e)
• Agriculture released 173.4 million metric tons CO2e
• 28.3% of total emissions
  

Of note: "emissions increases from enteric fermentation and animal waste management more than offset small decreases in emissions from rice cultivation and crop residue burning. Of total estimated methane emissions from agricultural activities, 93 percent (170.9 MMTCO₂e) results from livestock management, of which 68 percent (115.6MMTCO₂e) can be traced to enteric fermentation in ruminant animals and the remainder (55.3 MMTCO₂e) to anaerobic decomposition of livestock wastes. A small portion of U.S. agricultural methane emissions result from crop residue burning and wetland rice cultivation."(2)

We need to calculate the other ag and food emissions from other data sets.


Nitrous Oxide
N2O is found in ag primarily from fertilizer application and management of solid waste from animals . If applied properly as a fertilizer, nitrogen is taken up by the plants, but "Indirect emissions from nitrogen fertilization result from adding excess nitrogen to the soil, which in turn enriches ground and surface waters, such as rivers and streams, and results in emissions of nitrous oxide."(3)

What we do know:

• Nitrous oxide has a GWP rating of 296.
• Total U.S. N2O emissions for 2005 were 1.2 million metric tons
• 366.56 million metric tons CO2e
• Agriculture (what is measured) released 279.9 million metric tons CO2e
• 76.4% of total emissions
  

Of note: "Nitrogen fertilization of agricultural soils accounted for 78 percent of U.S. agricultural emissions of nitrous oxide in 2005. Nearly all the remaining agricultural emissions (22 percent) can be traced to the management of the solid waste of domesticated animals."(4)

This means that nitrogen fertilization adds 218.3 million metric tons of nitrous oxide emissions, which is 60% of total U.S. nitrous oxide emissions from this one act. Now, nitrogen is a critical component to plant fertilization. The question is: how do we make that fertilizer, and are we applying efficiently?

Another question that arises is: why the increase in nitrous oxide in the last couple years? Is our land yielding less and therefore requiring more fertilizer?

Sources:
(1) http://epa.gov/climatechange/emissions/downloads06/06Agriculture.pdf
(2) ibid.
(3) http://www.eia.doe.gov/oiaf/1605/ggrpt/nitrous.html
(4) ibid.

Ag Emissions and their Global Warming Potential, part 1

There is a lot of buzz about carbon emissions and their impacts on global warming. But what other emissions are heating up the planet?

The UN's Intergovernmental Panel for Climate Change (IPCC) has become the trusted international body for much of this info. They track different gases in relation to their Global Warming Potential (GWP). The DOE's Energy Information Administration (EIA) has a very good definition about GWP and which gases are considered.

The main item I want to highlight right now is that the GWP ranks gases according to their carbon dioxide equivalent, the "radiative efficiency (heat-absorbing ability) of each gas relative to that of carbon dioxide (CO2 ).(1)". So, while CO2 while has a GWP rating of 1 (against itself), Methane (CH4) has a GWP of 23, and Nitrous Oxide (N2O) a GWP rating of 296. There are ten other gases that are tracked, but these three are the more commonly discussed .

The EPA's U.S. Greenhouse Gas Inventory Reports tracks the gas emissions and sinks (where GHG gases are taken in/reduced), and has a chapter devoted to agriculture impacts. It has a graph of GHG emissions from 2004 and states that "In 2004, the agricultural sector was responsible for emissions of 440.1 teragrams of CO2 equivalent (Tg CO2 Eq.), or 6 percent of total U.S. greenhouse gas emissions. " The report, though, only measures a few ag components: enteric fermentation in domestic livestock, livestock manure management, rice cultivation, agricultural soil management, and field burning of agricultural residues. There is a lot more that needs to be included to understand the full GHG impacts of our food system, and then what potential solutions exist for reducing our carbon equivalent footprint.
Sources
(1) US DOE EIA website page Global Warming Potentials, viewed April 1, 2007.

Carbon Footprint of a Bag of Potato Chips

Across the pond in the UK, the dinosaur in our food is being uncovered. Working with an emerging program from the Carbon Trust to develop a label for carbon in products, Walker Chips, a division of Pepsico, is researching the amount of carbon in a bag of their popular potato chips. While this work is prelminary, it shows the motivation, and business incentive, to track the energy and carbon use in our food.

So how much energy do we use to make ... energy?

I am working hard to nail down The Number that represents how many calories of fuel energy it takes to make one calorie of food. My previous post about dinosaurs in your food describes how this Number is on average 10 calories of fuel to make one calorie of food.

So where does this number come from? Below is a narrative followed by references to the researchers mentioned.

I accept the 10:1 ratio because I have read various data sets and combed numerous papers and studies related to this issue. Further research on this issue is needed, something I am pursuing every day, and I will revisit this ratio if needed.

The ratio is based off of a complex number of variables: amount of energy used in the food system, definition of food system used, amount of calories per person per day to be considered, the role of import and exports, and what percentage of total U.S. energy is used by the food system.

Pimentel and, separately, Hall have estimated the average to be 10:1, while Heller/Keoleian has estimated 7.3:1. Heller/Keoleian say that the food system consumes 10.2 quadrillion Btu's (quads) of energy and provides 1.4 quads back out, based off a diet of 3,800 calories per person per day (because we produce more food than we need, eat too much of it, and then throw some away). If we use a 2,500 calorie diet, we would get an 11:1 ratio; a 2,000 calorie diet means a 13.8:1 ratio.

On the side, grain-fed beef requires thirty-five calories for every calorie of beef produced (Horrigan), and a can of diet soda that provides maybe 1 calorie of energy needs 2,200 calories to produce (70% tied up in the aluminum can)(Heller/Keoleian).

I am still dissecting Heller/Keoleian's comprehensive paper. Heller/Keoleian estimates food energy use at 10% of total U.S. energy. Hendrickson studied 8 different studies from the 1970's and found an average for food system energy use to be 15.6%. This suggests we are already reducing energy use in ag. The Earth Policy Institute (EPI) created some nice graphs showing total U.S. and farm energy use base off the more current numbers. In one graph EPI show the whole U.S. food system uses 10.25 quads of energy (10,250 quadrillion Btu's) and ag production accounts for 21% of energy use, or 2.125 quads. What

What I take from this is this: if Heller/Keoleian are correct that ag uses 10% of energy, this number would roughly align with the 1.691 quad number, but if we use the 21% figure that comes from Heller/Keoleian, the amount of embedded energy (and therefore the calorie ratio) is much higher than Heller/Keoleian report. I am trying to get hold of the Heller/Keoleian team to ask them about these discrepancies.

In the meantime I accept 10:1 to be an average ratio I can support. I will keep resarching this issue and updating as needed. Thanks to Cookson Beecher, a reporter with the Capitol Press (Olympia, WA), for asking me to source this fact.

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Articles:

Heller and Keoleian's article "Life Cycle-Based Sustainability Indicators for Assessment of the U.S. Food System" is very comprehensive.

One article by Pimentel and Giampietro is "The Tightening Conflict: Population, Energy Use, and the Ecology of Agriculture".

Sustainable Table has a good article "Fossil Fuel and Energy Use" with strong references at the bottom.

Sources:
Hall, C. A. S., C. J. Cleveland, and R. Kaufmann, "Energy and Resource Quality" Wiley Interscience, New York: 1986.

Heller, Martin C., and Gregory A. Keoleian, "Life Cycle-Based Sustainability Indicators for Assessment of the U.S. Food System", Ann Arbor, MI: Center for Sustainable Systems, University of Michigan, 2000.

John Hendrickson, “Energy Use in the U.S. Food System: A Summary of Existing Research and Analysis” Sustainable Farming, Vol. 7, No 4, 1997

Horrigan, Leo, Robert S. Lawrence, and Polly Walker. "How Sustainable Agriculture Can Address the Environmental and Human Health Harms of Industrial Agriculture." Environmental Health Perspectives 110, no. 5 (May 5, 2002)

David Pimentel and Mary Pimentel, "Energy Use in Fruit, Vegetable, and Forage Production", in "Food, Energy, and Society", ed. D. Pimentel, and M. Pimentel, revised edition. University Press of Colorado, Niwot, CO, 1996,
pp. 131-147.

So What is a Quad?

(Didn't think I would need to know this, but then again I didn't know what I didn't know)

A Quad is a term for a quadrillion Btu's of energy use. 1,000,000,000,000,000 British thermal units. 1 QBtu equals the annual energy output of 40 1,000MW power plants (1).

So what does that have to do with the price of bread? I'm getting to that; but for now let's take a look at the post about Energy Use In Food. As the graphic shows from the year 2000, the US food system used 10.25 quadrillion Btus of energy. That's the same amount as the annual energy output of 410,000 1,000 MW power plants.

For comparison, a modern wind turbine is capable of generating 1-2 MW of energy. The entire installed wind energy capacity of the U.S. is 11,603 MW (2).

The total U.S. energy supply is 100.278 QBtu (3).

Now if we look at the energy use graph in the other post: this means the US food system use 10% of our energy output. Some articles have said 17% on average, but I am guessing that some of that research, being from the late 70's and early 80's (4), is outdated, and that the US energy supply growth has been faster than the growth of energy use in the food system. Still, 10% is a Big Number, and if we are serious about reducing our carbon emissions then we have to include reducing the amount of energy we use to grow the food we eat.

Sources:
(1): Architecture 2030 website, "U.S. Energy Consumption, Greenhouse Gas Emissions"
(2): American Wind Energy Association (viewed Mar 9, 2007)
(3): Energy Information Administration Annual Energy Overview (2005)
(4): See John Hendrickson, " Energy Use in the U.S. Food System: a summary of existing research and analysis," Center for Integrated Agricultural Systems, UW-Madison

Energy Use on the Farm

A previous post mentioned an Earth Policy Institute report that discussed the amount of oil in food. From that same article comes this graphic showing what type of energy is used on the farm.

Source: Earth Policy Institute, Oil and Food: A Rising Security Challenge - DATA, May 9, 2005

Energy Use in Food, Part 2

There is a good article entitled "Oil and Food: A Rising Security Challenge" by Danielle Murray
at the Earth Policy Institute. From the article and an accompanying page with wonderful graphs (and sources) comes this graphic that shows where energy is used in ag. It's numbers are similar
to a previous post on this issue.

Sources
Primary: M. Heller and G. Keoleian, Life-Cycle Based Sustainability Indicators for Assessment of the U.S. Food System, Ann Arbor, MI: Center for Sustainable Systems, University of Michigan, 2000, p. 41
Secondary: Earth Policy Institute, Oil and Food: A Rising Security Challenge - DATA, May 9, 2005