Most consumers do not understand
today's highly complex global food system. Much of the food production and
processing occurs far away from where they live and buy groceries.
External environmental and community costs related to the production,
processing, storage, and transportation of the food are seldom accounted for in
the food's price, nor are consumers made aware of these external costs.
Examples of external environmental costs are the increased amount of fossil
fuel used to transport food long distances, and the increase in greenhouse gas
emissions resulting from the burning of these fuels.
Local and regional food systems,
where farmers and processors sell and distribute their food to consumers within
a given area, may use less fossil fuel for transportation because the distance
from farm to consumer is shorter. This paper discusses transportation
from farm to point of sale within local, regional, and conventional food
systems. Using fresh produce and other foods as examples, we considered miles
traveled, fossil fuels used, and carbon dioxide emissions, and assessed
potential environmental costs.
A food mile is the distance food
travels from where it is grown or raised to where it is ultimately purchased by
the consumer or end-user. A Weighted Average Source Distance (WASD)
can be used to calculate a single distance figure that combines information on
the distances from producers to consumers and amount of food product
transported. U.S. Department of Agriculture Agricultural Marketing
Service produce arrival data from the Chicago, Illinois terminal market were
examined for 1981, 1989, and 1998, and a WASD was calculated for arrivals by
truck within the continental United States for each year. Produce
arriving by truck traveled an average distance of 1,518 miles to reach Chicago
in 1998, a 22 percent increase over the 1,245 miles traveled in 1981.
A WASD was calculated for a
sampling of data from three Iowa local food projects where farmers sold to
institutional markets such as hospitals, restaurants, and conference centers.
The food traveled an average of 44.6 miles to reach its destination, compared
with an estimated 1,546 miles if these food items had arrived from conventional
national sources.
Would there be transportation fuel
savings and reduction in carbon dioxide (CO2) emissions if more food
were produced and distributed in local and regional food systems? To
answer this question, we calculated fuel use and CO2 emissions to
transport 10 percent of the estimated total Iowa per capita consumption of 28
fresh produce items for three different food systems. A number of assumptions
were used regarding production origin, distance traveled, load capacity, and
fuel economy to make the calculations. The goal was for each of the three
systems to transport 10 percent by weight of the estimated Iowa per capita
consumption of these produce items from farm to point of sale.
The conventional system
represented an integrated retail/wholesale buying system where national sources
supply Iowa with produce using large semitrailer trucks. The Iowa-based
regional system involved a scenario modeled after an existing Iowa-based
distribution infrastructure. In this scenario a cooperating network of Iowa
farmers would supply produce to Iowa retailers and wholesalers using large
semitrailer and midsize trucks. The local system represented
farmers who market directly to consumers through community supported
agriculture (CSA) enterprises and farmers markets, or through institutional
markets such as restaurants, hospitals, and conference centers. This system
used small light trucks.
The conventional system used 4 to
17 times more fuel than the Iowa-based regional and local systems, depending on
the system and truck type. The same conventional system released from 5 to 17
times more CO2 from the burning of this fuel than the Iowa-based
regional and local systems.
Growing and transporting 10
percent more of the produce for Iowa consumption in an Iowa-based regional or
local food system would result in an annual savings ranging from 280 to 346
thousand gallons of fuel, depending on the system and truck type. The high end
of this fuel reduction would be equivalent to the average annual diesel fuel
use of 108 Iowa farms. Growing and transporting 10 percent more of the produce
for Iowa consumption in an Iowa-based regional or local food system would
result in an annual reduction in CO2 emissions ranging from 6.7 to
7.9 million pounds, depending on the system and truck type.
These fuel savings and CO2 reductions
may seem small when considering total fuel use and CO2 emissions in
Iowa, but our estimates represent less than 1 percent of total Iowa food and
beverage consumption by weight (not including water). If a higher
percentage of other foods and beverages were grown and/or processed in Iowa,
the reduction in fuel use and CO2 emissions from food transport
would undoubtedly be much greater.
This paper shows that fresh
produce transported to Iowa consumers under the current conventional food
system travels longer distances, uses more fuel, and releases more CO2
than the same quantity of produce transported in a local or Iowa-based regional
food system. Given that fuel expenses are only a small percentage of total
transportation and distribution costs, however, fuel energy costs will need to
rise significantly if they are the only factor considered in determining
whether local and regional systems are economically competitive with the
conventional system. Economic value must be assigned to the external
environmental cost of burning more fossil fuels and releasing more CO2.
The authors strongly urge that more baseline research be conducted comparing
the energy efficiency and external environmental costs of production,
processing, packaging, and transportation sectors of conventional, regional,
and local food systems.
A food system includes the
production, processing, distribution, sales, purchasing, preparation,
consumption, and waste disposal pathways of food. In Iowa and across the
nation, the level of interest in local and regional food systems -- where local
farmers sell their products to nearby consumers -- is growing. One
example of a local food system is community supported agriculture, which
establishes a partnership between farmers and consumers. In a typical
Iowa community supported agriculture (CSA) enterprise, consumers pay a given
amount to a farmer or group of farmers before the start of the growing season,
sharing in some of the risk of producing the food. The food is then
delivered directly to the consumer or is picked up at a designated
location. Other examples of local food systems include farmers markets,
roadside stands, on-farm sales, pick-your-own operations, production/processing/retail
enterprises, and sales to hotels, restaurants, bed and breakfast inns, and
institutions.
Most consumers do not understand
the current national and global food production system, in which most of the
food production and processing occurs far away from where they live and buy
their groceries. Yet an increasing number of consumers have shown an interest
in locally or regionally produced foods. Researchers at Oregon State
University surveyed both working class and more affluent community residents in
the Portland area and found that 44 percent of residents in both groups
expressed moderate to strong support for buying local products.[1] Practical Farmers of Iowa recently
interviewed Iowa wholesale food distributors, retail store managers, chefs,
institutional food service managers, and cooperative buyers as part of a
Leopold Center-supported project. All of the representatives expressed an
increased interest in buying Iowa-grown meat and produce to satisfy rising
consumer demand, and also agreed that there is a small but expanding market for
organically or sustainably grown products.[2]
In the past 30 years there has
been a significant global increase in fossil fuel use. One reason
for the rise in U.S. fossil fuel use is the increased use of trucks to
transport goods. In 1965, there were 787,000 combination trucks
registered in the United States, and these vehicles consumed 6.658 billion
gallons of fuel.[3] In
1997, there were 1,790,000 combination trucks that used 20.294 billion gallons
of fuel.[4]
Many of these trucks transport food throughout the United States. A
recent study indicated that in California alone more than 485,000 truckloads of
fresh fruit and vegetables leave the state every year and travel from 100 to
3,100 miles to reach their destinations.[5]
The predicted peak in world oil
production, according to petrogeologists and other oil experts, will occur in 5
to 20 years.[6] [7] After that time oil increasingly will be
more expensive to obtain. Yet projections are for motor gasoline and diesel
fuel demand to increase 1.4 and 2.3 percent per year, respectively, through the
year 2020.[8]
The burning of these fossil fuels
releases carbon dioxide (CO2) and other gases known as greenhouse
gases that absorb heat and may contribute to an increase in global warming.
Considering all sectors of the economy, Iowa emits 29 tons of carbon dioxide
annually on a per capita basis.[9]
Total U.S. greenhouse gas emissions in 1999 were 11.6 percent higher than 1990
emissions.[10] The
largest source of CO2 and overall greenhouse gas emissions in the
United States was fossil fuel combustion, accounting for 80 percent of
global warming potential (GWP)[11]
-weighted emissions in the 1990s.[12]
Estimates suggest that a doubling
of atmospheric carbon dioxide will result in an increase of 4.5° F in
the planet's average annual temperature.[13] Recently the Intergovernmental Panel
on Climate found stronger evidence of the human influence on climate change.
According to the scientists' estimates, earth's average surface temperature
could be expected to increase by 2.7° F to nearly 11° F by
the end of this century if greenhouse emissions are not curtailed.[14]
The Kyoto Global-Warming Accord Treaty,[15]
signed by the United States in 1998, calls for industrial countries to achieve
a 5.2 percent reduction of heat-trapping greenhouse gases from 1990
levels. The United States, the world's largest emitter of greenhouse
gases, would have to make cuts of seven percent. [16] In late March 2001, the Bush
administration opposed the Kyoto Accord on the grounds that ratification would
put an unfair burden on the United States and damage the economy.[17]
Efforts to persuade the United States to endorse the Kyoto Accord at the
European Union/United States summit in June 2001 ended in stalemate.[18]
Certain states, regions, and
countries are said to have "comparative advantages" to producing food
at the cheapest possible cost. But external environmental and social
costs related to food production, processing, storage, and distribution are
seldom accounted for in the price of the food.[19] It is argued that if these costs were
internalized, such "comparative advantages" would be significantly
reduced or eliminated entirely. Examples of environmental external costs are
the increased amount of fossil fuel used to transport food and the increase in
greenhouse gases emitted as the result of the burning of those fuels. One
likely advantage to local and regional food systems is the reduced distance
that the fresh or processed food travels from farm to point of sale.
Shorter transportation distances may mean less fossil fuel is burned and fewer
greenhouse gases are released into the atmosphere.
Using fresh produce and other
foods as examples, this paper will discuss transportation and distribution
within local, regional, and conventional food systems, determining miles
traveled, fossil fuels used, and greenhouse gases released.
1.
Provide a brief overview of the changes in
Iowa's food system.
2.
Provide an overview of the research on energy
use in the food system, with emphasis on the transportation/distribution
sector.
3.
Using several global, Iowa, and Midwest
examples, discuss the distances that food travels (from farm to point of sale)
and compare distances between local and conventional systems.
4.
Using fresh produce as an example, compare
miles traveled, fossil fuel used, and carbon dioxide emitted in the transport
sector of several food systems.
5.
Make recommendations for action (for consumers,
farmers, food retailers and brokers, researchers and educators, and policy
makers) to document external costs regarding fossil fuel energy use in the
conventional food system, reduce transportation-related fuel use and CO2
emissions in food systems, and examine potential benefits of local and regional
systems.
Although less than 7 percent of
Iowans make their living by farming, Iowa remains a predominantly agricultural
state, with approximately 33 million acres of land in farms.[20] Table 1, developed by Michael Carolan
in the Iowa State University Department of Sociology and based on the U.S.
Agricultural Census records, shows the number of commodities produced for sale
on at least 1 percent of all Iowa farms from 1920 to 1997. Iowa
produced 34 different commodities on at least 1 percent of its farms in 1920,
including food crops such as apples, potatoes, cherries, plums, grapes, raspberries,
strawberries, sweet corn, and pears. In that same year, ten different
commodities were produced on over 50 percent of Iowa's farms.
During the decades following World
War II, agriculture became increasingly specialized, with many states focusing
their agricultural production on certain crop and livestock enterprises. Using
federal and state incentives, Iowa centered its agricultural production on
commodities such as corn, soybeans, hogs, and cattle. Table 1 illustrates this
decline in diversity; by the 1970s there were no fruits or vegetables produced
on at least 1 percent of Iowa's farms. By 1997, only corn and soybeans were
produced on over 50 percent of Iowa's farms.
With a decline in production
diversity came a decrease in processing of certain crops. According to a
1922 report, Iowa led the world in canned sweet corn production.[21] In
1924 Iowa processed locally grown sweet corn at 58 canning factories in 36
different counties.[22] By
1998 sweet corn and other vegetables were processed at only two Iowa canning
facilities.[23]
With the possible exception of
livestock for meat production, most Iowa farms no longer produce food to supply
Iowa consumers directly. The majority of the crops Iowa farmers produce leave
the state as raw commodities, and processors add more value before purchase by
the consumer or buyer. The change in Iowa's agriculture over time has
brought about an increasing reliance on food from outside sources. For
example, in 1870 nearly 100 percent of the fresh apples consumed in Iowa were
grown in the state. By 1925, roughly 50 percent of the apples consumed were
grown in Iowa.[24] In
1999, Iowa grew approximately 15 percent of the fresh apples consumed in the
state.[25] It
is assumed that other food items once produced on many Iowa farms have followed
a similar pattern of decline.
There is a lack of baseline data
on Iowa production and processing used for in-state consumption. In recent
years, 10 percent has been used as an estimate of how much of the food Iowans
consumed is grown in the state, but this figure is at best only an educated
guess. A 1985 report estimated that more than 90 percent of Iowa's produce
demand is provided for by sources outside of the state.[26] The report indicated that Iowa farmers
grew a small fraction of the fresh produce bought during the summer months by
Iowa produce wholesalers and distributors for sale within the state.[27]
This purchasing trend holds true in 2001.[28]
A thorough examination of energy
use in the food system is beyond the scope of this paper. An excellent 1996
summary of research and analysis of energy use in the food system, written by
John Hendrickson, covers many important studies and is recommended as further
background for the reader.[29]
The gasoline shortages and a perceived energy crisis in the 1970s prompted a
number of studies on energy use in the food system. Hendrickson's research
points to a critical need to replicate studies performed in the 1970s.
New studies on energy use in all
sectors of the food system are needed for a number of reasons. The nation is
experiencing serious energy shortages once again, with rising prices and energy
blackouts in California and other states. Increased efforts to conserve
fossil fuels are being explored at state and federal levels. With increased
interest in local and regional food systems, it is important to document whether
these systems are more energy efficient than conventional systems, and whether
an increased use of such systems will contribute to a reduction in fossil fuel
use and greenhouse gas emissions.
Table 2, taken from John
Hendrickson's research, averages the findings from nine studies that document
energy use in various sectors of the food system.[30] The table shows that the food
system accounts for almost 16 percent of total U.S. energy consumption, similar
to David Pimentel's 1989 estimate of 17 percent. Table 2 also shows that
transportation accounted for 11 percent of the energy use within the food
system, considerably less than agricultural production (17.5 percent) and
processing (28.1 percent).
Energy use by sectors also varies
tremendously by the type of food considered. For example, for a
one-kilogram loaf of bread more than 70 percent of the energy is used in the
production and processing sectors.[31]
For a one pound can of corn, those same two sectors use only 27 percent of the
energy, with packaging accounting for over one-fourth of the total energy used.[32]
The energy used to transport a one pound can of corn home and to prepare it
exceeds the energy needed to produce the corn.[33]
Life Cycle Assessment (LCA) is a
method for performing an integral analysis of the environmental impacts of
products in a "cradle to grave" fashion.[34] [35]
Energy consumption within the life cycle of a product is typically calculated
while performing an LCA. The LCA method was originally developed for use
with industrial products, but recent research has investigated the extent to
which the LCA method is suitable for use in agricultural systems.[36] One such
study estimated the total life cycle energy consumption of apples and pears to
be 23 megajoules per kilogram (MJ/kg).[37]
(For reference purposes, one MJ will light a 100-watt light bulb for 2.8 hours.[38])
In another study, the energy needed for a fast food-type hamburger was
estimated to be between 24 and 65 MJ/kg.[39] Ground beef required the most energy
of all food products needed for the hamburger (other products included were
bun, lettuce, cheese, pickles, and onions).
Several studies have compared
energy consumption for crops grown locally versus those imported. One
study found that sourcing fresh peas locally required nearly three times less
energy compared to imported peas.[40]
A Swedish study compared the energy consumption of Swedish and imported carrots
and found that energy consumption for the imported carrots was double that of
the domestic produce.[41]
A recent University of Michigan
study used an LCA approach to develop and present a broad set of sustainability
indicators of the U.S. food system.[42]
The assessed indicators showed that the U.S. food system is not economically,
socially, or environmentally sustainable. The study concluded that the most
effective way to develop a more sustainable food system is to change attitudes
and behaviors about food consumption.
The 1999 energy bill for marketing
food in the United States totaled $21.6 billion, accounting for 3.5 percent of
retail food expenditures.[43] It
is estimated that 6 to 12 percent of the consumer dollar spent on food consumed
in the home represents transportation costs.[44] From 1985 through 1991, the average
transportation charge for Florida tomatoes shipped to the upper Midwest was 6.3
percent of the retail cost.[45]
Oil prices affect the trucking industry, which uses diesel fuel. Declining
diesel oil prices through the 1990s tended to restrain food transportation cost
increases.[46]
A food mile is the distance food
travels from where it is grown or raised to where it is ultimately purchased by
the consumer or other end-user. One 1969 estimate of miles traveled by food in
the United States cited an average distance of 1,346 miles.[47] Calculations made by John Hendrickson
using a 1980 study examining transportation and fuel requirements estimated
that fresh produce in the United States traveled an estimated 1,500 miles.[48] Fresh
produce arriving in Austin, Texas, was estimated to travel an average of 1,129
miles.[49] An
analysis of the USDA Agricultural Marketing Service's 1997 arrival data from
the Jessup, Maryland, terminal market found that the average pound of produce
distributed at the facility traveled more than 1,685 miles.[50] This same study showed the average
distance for fruits to be transported was 2,146 miles, while the average for
vegetables was 1,596 miles.[51]
In developed, industrial nations,
food appears to be traveling farther to reach the consumer. Agricultural
imports into the United States increased 26 percent by weight from 1995 to
1999.[52] One
metric ton of food transported by road in the United Kingdom traveled an average
distance of 77 miles in 1998 compared with 51 miles in 1978.[53] A Swedish study of food miles used the
ingredients from a Swedish breakfast (apple, bread, butter, cheese, coffee,
cream, orange juice, and sugar) to sum the distances that each food traveled
from the producers to consumer. The mileage estimated for the meal was
equivalent to the circumference of the earth.[54]
Prior to the late 1960s, most
Americans ate table grapes when the local and California markets could supply
them -- roughly from June through December. Since then, Americans
have nearly tripled their table grape consumption from 2.52 pounds per person
(per capita utilization) in the 1972/73-market year to 8.21 pounds per person
during the 1999/2000-market year.[55]
A major reason for this increase in consumption is the increase in the amount
of imported grapes from Chile and other Southern Hemisphere countries during
winter and early spring when California grapes are not available. The amount of
imported grapes during this period (as a percentage of total consumed) rose
from 4 to 45 percent, while exports of California grapes remained fairly
steady.[56]
The significant increase in imported grapes implies an increase in the average
distance that table grapes travel to reach the U.S. consumer.
One way to estimate food miles is
to use a weighted average source distance (WASD).[57] The WASD from production source to
consumption endpoint is a single distance figure that combines information on
distances from producers to consumers and the amount of food product
transported. To provide perspective on the increase in food miles traveled, we
have calculated the WASD for table grapes consumed in Iowa in three different
years.
The formula for the WASD is:
S (m(k) x d(k))
WASD = ——————
S m(k)
where:
k =
different locations of the production origin,
m =
amount consumed from each location of consumption origin, and
d =
distances from the locations of production origin to the point of consumption.
For these calculations, we made a
number of assumptions:
· Iowa's average per capita table grape consumption is
equivalent to the U.S. average, and the consumption reference point is Des
Moines.
· Distances are estimated by using latitude/longitude
coordinates from an Internet site (http//:indo.com/distance/) to determine a
direct distance that is "as the crow flies" between the two points
rather than actual transport route. We chose to go with this distance
estimation because transportation routes vary for table grapes imported into
Iowa from Chile and South Africa.
· We have used a 1 percent floor for these calculations; only
states or countries providing 1 percent or more of the total poundage of table
grapes were included.
· In 1972/73 accurate import data for that year were not
readily available on which countries provided fresh grapes to the United
States, but it is very likely that the majority of imported grapes came from
Chile. Almost all of the remaining 96 percent of the table grapes was
grown in California.
WASD calculations for three
production years for table grapes can be found in Table 3. The 1972/73 WASD was
calculated at 1,590 miles. In 1988/89, the WASD had increased to 2,848
miles, an 89 percent gain over the 1972/73 figure. Most of this increase in
distance can be explained by the significant increase in exports of Chilean
table grapes to the United States and the corresponding increase in annual
consumption. In 1998/99, the WASD was relatively unchanged at 2,839
miles, primarily because of the increase in Mexican table grape imports
relative to the total amount of table grapes consumed. (Mexican table grapes
had a slightly shorter transport distance from production [Mexico] to
consumption point [Des Moines] than the California-grown grapes.)
The WASD for table grapes has been
calculated in other countries. In Sweden, a WASD for table grapes was
calculated using a consumption point in Stockholm, Sweden. The WASD increased
by almost 100 percent from 1965 to 1992.[58] This change reflects an increase in
imports of table grapes grown in Chile, Australia, and the United States.
The WASD can be estimated from production
and shipping records for various fresh fruits, vegetables, meats, and other
foods. It is much more complicated to calculate the WASD for
multi-ingredient processed products.
One late 1970s estimate indicated
that in the United States approximately 60 percent of food and related products
were transported from the farm by truck and the remaining 40 percent by rail.[59] In
the past 25 years, with an improved road infrastructure in the United States
and other developed nations, the amount of food transported by truck has
increased dramatically. According to a 1996 USDA study, nearly 93 percent of
fresh produce transported between cities in the United States was moved by
truck.[60]
The USDA's Agricultural Marketing
Service (AMS) tracks shipments and exports of fresh fruits and vegetables by
commodities, modes of transportation, origins, and months in the calendar year.
The AMS also tracked produce arrivals at various terminal markets throughout
the United States until budget limitations forced the elimination of this data
collection in 1998.[61]
Terminal markets for produce have declined in importance in the United States;
currently there are only 22 major terminal markets that handle an estimated 30
percent of the volume of the nation's produce.[62] The decline in terminal market share
is a reflection of the increased purchasing power of integrated
wholesale-retail buying entities.[63]
Although terminal market share has
declined, the arrival data collected through 1998 provide a realistic picture
of where produce comes from during the calendar year. To provide an upper
Midwest perspective on how far food travels, we examined the arrival data at
the Chicago, Illinois terminal market collected by the AMS for the years 1981,
1989, and 1998. Chicago was chosen over other terminal markets because of
its proximity to Iowa and the assumption that it approximated the purchasing
source percentages of integrated wholesale-retail produce buyers in Iowa.
The Chicago terminal market
arrival data document the total amount of produce that arrived at the market
from states, countries, and territories. We used the data to calculate
two WASDs; one for produce arriving from locations in the continental United
States by truck, and one for total arrivals by truck that originated from
outside of the continental United States. We calculated arrivals by truck
and rail as a percentage of total arrivals for produce grown within and outside
the continental United States. We also calculated arrivals by truck from
California and Florida as a percentage of total arrivals. The following
assumptions were made in the calculations:
· For the truck WASD calculations, distances from the
production origin within the continental United States and Canada to the
terminal market were estimated by using a city located in the center of each
state as the production origin. (In Canada we took the average distance from
the center of two major produce areas to Chicago.) Then we calculated a one-way
road distance to Chicago using the Internet site Mapquest (mapquest.com).
· Distances from Puerto Rico, Hawaii, and other countries to
Chicago were calculated using the Internet site (http//:indo.com/distance/)
which uses latitude and longitude to determine a direct distance that is
"as the crow flies" between the two points rather than actual
transport route. This was done because it is difficult to find the data
to determine the shipping routes taken to each customs port in the United
States, and transportation routes from the port to Chicago.
Table 5 compares the distances
traveled for locally and regionally grown foods used in three meals compared
with the distances traveled if those foods came from conventional sources
outside of the state. The average total distance for the three locally
sourced meals was 1,198 miles. The average total distance for the meals
using the same meal ingredients obtained from conventional sources was 12,558
miles, more than 10 times the distance. WASDs were not used in this example.
A number of local food system
projects, including several supported by the Leopold Center, have been
initiated in Iowa over the past several years. These projects have reported
success in increasing sales of locally grown and processed produce, meats, and
beverages to hotels, restaurants, and institutions such as hospitals,
universities, schools, restaurants, workplace cafeterias, and conference centers.
To contrast the distance food travels in a locally-based versus a conventional
system, we compared WASDs for several Iowa institutional projects with WASDs
for a conventional system sourcing the same products within the continental
United States.
A sample of food distribution data
from three Leopold Center-funded local food projects in Black Hawk, Johnson,
and Story counties was used. Data were available on total pounds of
product delivered, delivery location, and address of the grower. Food items
included meat and produce. One-way distance from the farm to institution was
estimated using the Internet site Mapquest (mapquest.com). Using this
information, we estimated a WASD for each project, and a combined WASD across
all three projects. We then calculated a WASD for each project site and a
combined WASD across all project sites for the same food items, assuming they
were produced in a state that currently supplies Iowa with a significant amount
of that food.
Table 6 shows the WASD
comparisons. The local food traveled an average distance of 44.6 miles
across all food projects, while that same food would likely travel an average
of 1,546 miles if it came from conventional sources. When considering
produce only, the local food traveled an average distance of 37.9 miles, while
the produce would likely travel an average of 1,638 miles if it came from
conventional sources.
.
As mentioned in Table 2 and in the
section "Energy use in the food system" the food system was estimated
to account for 16 percent of total U.S. energy consumption. Agricultural
activities were responsible for 7.7 percent of total U.S. greenhouse gas
emissions in 1997.[64]
Energy use and gaseous emissions from the transport of food vary by mode of
transportation. Table 7 shows the estimated values for energy consumption
and for carbon dioxide and other gaseous emissions for four transportation
modes. Clearly, air transportation is the least energy efficient method
and produces more emissions in transporting food or other goods, followed by
road (truck), rail, and water.
Reductions in transport-related
carbon dioxide emissions when food items are sourced locally rather than
conventionally have been documented in several research studies. A recent
British study showed that purchase of local apples resulted in an almost 3,000
percent reduction in energy use and 87 percent lower carbon dioxide emissions
than apples imported from New Zealand.[65]
The mode of transportation, however, must be taken into account before assuming
that energy use and CO2 emissions will be lower for food that is
transported for shorter rather than longer distances. Table 7 shows
that a given amount of food transported by water could travel seven times
farther than the same amount of food transported by road (truck) and still not
use more energy or release more greenhouse gases.
Comparing fuel
use and CO2 emissions for three food distribution systems
What type of transportation fuel
savings would be realized if Iowa grew more of its own food? How much of a
reduction in CO2 emissions would result from the fuel savings? To
help answer these questions, we have estimated fuel use and CO2 emissions
for transporting from the farm (production origin) to the point of sale 10
percent of 28 different fresh produce items that Iowans consume annually, using
three different food systems.
For the purposes of this
comparison, we define these three food systems as follows:
Conventional system: This is an integrated retail/wholesale buying system in
which national sources supply Iowa with a significant percentage of its produce
through retail supermarkets, restaurants, and other institutional markets
served by brokers and distributors. Iowa now receives a good deal of produce
from other countries, but to simplify calculations we chose to focus on
national sources. This system uses large semitrailer trucks for transport.
Our intent was to determine
whether there would be transportation fuel savings and CO2 emission
reductions if 10 percent more of the fresh produce consumed by Iowans was grown
in local or regional systems. For these calculations, we made a number of
assumptions.
To estimate food consumption:
· National per capita consumption data[66] (three-year average for 1997-99) were used
to estimate Iowa consumption totals for all 28 selected produce items.
To select production sources for
the conventional system:
· We selected a state that we were confident grew at least 10
percent of the total of Iowa's annual consumption for each of the 28 produce
items. These states have a track record of supplying a significant amount of
the demand to the upper Midwest during Iowa's growing season. Arrival data for
1998 from Chicago's terminal market were used as a reference. The
produce/state pairings made to estimate distances can be found in Table 8.
To estimate one-way mileage in the
three systems:
· For the conventional system one-way mileage from the center
of the state to Des Moines, Iowa, were used to estimate the distance from farm
to point of sale. Des Moines was chosen as the destination point because
it is close to the center of Iowa, is at the intersection of the state's two
major interstate highways, and is a major distribution point for produce.
Distances were estimated by using the Internet site MapQuest (mapquest.com).
· For the Iowa-based regional system a distance of 82 miles
was estimated as a one-way average travel distance from farm to point of
sale. This number represented the average distance from 15 locations
uniformly spread across Iowa to the two closest major Iowa market or
distribution areas (Des Moines, Chariton, Cedar Rapids, Boone, Sioux City,
Davenport, and Omaha, Nebraska). Choosing the two closest major market areas
for each of the 15 locations provided 30 data points (15x2) for the estimation.
Distances were estimated by using the Internet site MapQuest (mapquest.com).
· For the local food transport system serving institutional
markets an average one-way distance of 38 miles would be used. This
estimate can be found in Table 5, where we calculated the average one-way
distance that local produce traveled across three institutional local food
system projects.
· For the local food transport system servicing CSA and
farmers markets an average one-way distance of 21.2 miles from farm to point of
sale would be used. This figure represents the average one-way distance
from the farm to Ames for all Ames downtown farmers' market vendors and regular
producers serving the Magic Beanstalk CSA. Produce distribution data (by
weight) was not readily available for this local system, so a WASD could not be
calculated.
· Backhauls were not included in any of the calculations
because the trucks often do not return directly to their original
destinations. For example, produce trucks from California traveling to
the upper Midwest may unload produce in Iowa, pick up another load of goods in
Iowa or another state, and then return to California.
To select transport vehicles, load
capacities, and fuel economies for the three systems:
· Calculations were made for produce in the conventional and
Iowa-based regional systems using heavy-duty semitrailer truck rigs that carry
40,000 pounds.[67] [68]
Five percent of the load would be container weight, for a total produce weight
per truck of 38,000 pounds. These heavy-duty trucks would use a gallon of
diesel fuel for every 6.1 miles they travel.[69]
· Calculations in the Iowa-based regional system were made
also for a midsize truck capable of hauling 14,500 pounds of produce, of which
5 percent would be container weight.[70]
These midsize diesel trucks would use a gallon of diesel fuel for every 8.5
miles they travel.[71]
Both semitrailer and midsize trucks are currently used to transport produce for
wholesale and retail markets in Iowa.
· For the local food system we selected a light
gasoline-fueled truck that could transport a maximum load of 1,635 pounds,[72] 5
percent of which is container weight. For our estimations the light
trucks will use a gallon of regular gasoline for every 17.2 miles they travel.[73]
Other assumptions:
· Fuel use calculations and CO2 emissions are
based on transporting produce from farm to point of sale. Fuel used and
emissions generated in production, in transport to an on-farm cooling facility,
in transport for indirect routes needed for processing or storage, or by
consumers to transport the produce from point of sale to home are not
considered. Indirect fuel use and CO2 emissions resulting from
manufacturing the trucks or building the roads are not considered.
· Each of the three food systems could supply 10 percent of
the estimated per capita consumption of the 28 selected produce items.
Table 9 compares the fuel used, CO2
released, and total distance traveled (from farm to point of sale) if 10
percent of the produce consumed in Iowa were distributed by conventional,
Iowa-based regional, and local systems. The conventional food system's
semitrailers had nearly 17 times higher fuel use and CO2 emissions
compared with the semitrailers in the Iowa-based regional system, and 8.5 times
higher fuel use and CO2 emissions than the midsize trucks in the
Iowa-based regional system. The conventional food system's
semitrailers traveled nearly 17 times farther than the semtrailers in the Iowa-based
regional system, and six times farther than the midsize trucks in the regional
system.
The conventional food system's
semitrailers used more than four times the fuel when compared with the local
food system's light trucks used for institutional markets, and emitted almost
five times the CO2, but only traveled 1.5 times as far as the light
trucks. The light trucks had to make more trips to deliver 10 percent of
the per capita consumption target. The conventional food system's
semitrailers used more nearly 7.5 times the fuel, emitted more than 8.5 times
the CO2, and traveled nearly three times as far as the local food
system's light trucks used for CSA and farmers markets.
Growing and transporting 10
percent more of the produce for Iowa consumption in an Iowa-based regional or
local food system would result in savings ranging from 280 to 346 thousand
gallons of fuel, depending on the system and truck type. The high end of this
fuel saving (found in the regional system) would be equivalent to the average
annual diesel fuel use of 108 Iowa farms.[74] The fuel cost savings (based on June
2001 fuel prices), depending on system and truck type, would range from
$440,377 to $546,393.
Growing 10 percent more of the produce
for Iowa consumption in an Iowa-based regional or local transport system would
result in a reduction in CO2 emissions of 6.7 to 7.9 million pounds,
depending on the system and truck type.
The calculated reductions in
fossil fuels and CO2 emissions are based on 10 percent of the
estimated Iowa consumption of 28 fresh fruits and vegetables grown in the
state. These reductions are quite small when considering potential savings of
the recommended options to increase fuel efficiency and reduce greenhouse gas
emissions made in Iowa's 1996 Greenhouse Gas Action Plan.[75] Ten percent of these 28 produce
items, however, represents less than 1 percent of total food and beverage per
capita consumption by weight (not including water) in Iowa.[76] If a higher percentage of meats,
processed foods, and beverages were grown and/or processed in Iowa, the
reductions in fuel usage and resulting CO2 emissions from transport
would be significantly higher.
Our intent was to estimate some of
the hidden environmental costs connected to the current conventional food
system's reliance on semitrailers traveling great distances to bring food to
Iowa. Using limited data and a set of assumptions, this study has estimated the
transportation fuel usage and CO2 emissions for three food systems.
A more comprehensive study might be undertaken to include backhauls and account
for produce arriving from other countries as well as the United States. One could
document specific vehicle load weights for each type of produce (for example, a
load of peppers will weigh less than a load of cucumbers), and track fuel
efficiencies for specific truck types across different food distribution
systems. A significant obstacle in undertaking such a comprehensive study is
the lack of available data from public sources.
Application of results: using
food miles to estimate fuel use and CO2 emission reductions without
local data
We have shown examples where food
transported in local and Iowa-based regional systems travels fewer miles, uses
less fuel, and emits less CO2 than a conventional system. Are there
simpler ways of estimating fuel consumption and CO2 reductions used
in food transport that might come from an increased reliance on local and
regional food systems, particularly when local data are not available? One
alternate approach is to develop a food system scenario where increased
reliance on local and regional food systems leads to a reduction in the average
distance food is transported (from production to point of sale).
We turn back to the produce
arrival data from the Chicago terminal market to develop an example. Our
analysis of produce arrival data at the Chicago terminal market showed that the
upper Midwest relies on both national and international sources to supply most
of its produce. If the upper Midwest relied more upon a multi-state regional
system to provide its produce, the average distance that produce would travel
from farm to point of sale would decrease.
Our intent was to estimate how
much fuel would be saved and CO2 not released if a multi-state
regional food system could reduce the average produce transport distance by a
certain target mileage. To estimate the possible reductions in fuel usage
and CO2 emissions, we hypothesized a multi-state regional system and
compared it to the conventional system. To make the calculations, we made
several assumptions.
· We defined the upper Midwest as a six-state region
including Iowa, Minnesota, Wisconsin, Indiana, Illinois, and Michigan, with
Chicago as market hub.
To estimate food consumption:
· National per capita consumption data[77] (three-year average for 1997-99) was used
to calculate per capita consumption for each of these six states for the same
28 fruits and vegetables identified in Table 8.
· Arrival data from the 1998 Chicago terminal market
indicated that 84 percent of the produce arriving from within the continental
United States came by truck, and the remaining 16 percent came by rail.
We reduced total consumption by 16 percent so produce traveling by rail would
not be included in our estimations.
To select transport vehicle type,
load capacity, and fuel economy for the hypothesized system:
· The system would use a semitrailer truck that can transport
40,000 pounds (five percent of the load would be container weight, for a total
produce weight per truck of 38,000 pounds) and get 6.1 miles per gallon of
diesel fuel.[78] [79]
· Backhauls were not considered.
To estimate a target reduction
distance:
· We subtracted the 1981 WASD from the 1998 WASD for arrival
by trucks in the continental United States (shown in Table 4) and found a
difference of 273 miles. We used that difference as our target reduction
distance.
If a regional production and
distribution system used for fresh produce for this six-state region reduced by
273 miles the average one-way distance that produce traveled by truck, this
reduction would translate into savings of 8.8 million gallons of diesel fuel
per year. The amount of CO2 emissions would decrease by 194.8
million pounds.
The infrastructure and
decision-making in the current food system are based on profitability, and
often do not take into account external environmental or community costs.
This paper has documented several cases and scenarios where food produced
within local or regional food systems travels fewer miles (from farm to point
of sale) than the food produced within a conventional system. The shorter
transportation distances for these local and state-based regional food systems
led to reduced transportation fuel use and CO2 emissions compared to
the conventional system. We hope that this study will encourage others
involved in local food system efforts to compare their transportation fuel use
and resulting CO2 emissions with the conventional system.
The energy crisis in California
has resulted in higher prices for cooling and storing California-grown produce
and other foods, resulting in higher selected food prices for distributors,
retailers, and consumers.[80] High
fuel costs have led to protests by independent truckers, who claim the
increases threaten their livelihoods.[81]
Rising fuel and electricity costs may make food distributors, brokers, and
retailers more receptive to using local and regional food systems.
Given that fuel expenses are only
a small percentage of total transportation and distribution costs, however,
fuel costs will need to rise significantly if they are the only factor
considered in determining whether local and regional systems are economically
competitive with the conventional system. According to
research conducted at Iowa State University in 1985, rising fuel costs did not
provide a competitive advantage to producing 13 different horticultural crops
in Iowa rather than shipping them in from other states.[82] This research, however, did not
assign economic value to the environmental benefit of reducing fossil fuel use
and greenhouse gas emissions. It also did not take into account the community
benefit to increasing markets for Iowa producers. Based on our consumption
estimates for the 28 fruits and vegetables discussed earlier in this paper, if
an additional 10 percent of these produce items were grown and sold in Iowa, it
would result in $54.3 million dollars in sales for Iowa farmers (based on
wholesale prices). These dollars would multiply several times in Iowa
communities rather than communities in other states or countries.
"Cause marketing" is
marketing that connects a business' product to a particular cause or set of
values, in the hope that those consumers with similar values will be more
likely to purchase the product.[83]
A 1997 marketing report indicated that price and quality being equal, 76
percent of consumers would switch to a brand of product they considered to be
supporting a good cause.[84]
Some consumers may buy a food product because it is locally grown, while others
may be interested in whether it is organic, protects soil and water resources,
or provides good wages and working conditions for the farm workers. Others may
be looking for several of these attributes. Collaborative cause marketing,[85] which
correlates different value sets with food product attributes, may answer their
needs.
We believe there is a segment of
the population who support environmental causes and are concerned about CO2
emissions and fossil fuel use. It is uncertain whether these
consumers see a move to a more local or regional food system as relevant to
their own cause. This paper helps to make the connection between food
choices, fossil fuel use, and greenhouse gas emissions. The information may be
useful for producers, processors, and retailers wanting to build relationships
with consumers concerned about these environmental issues.
Although food transported in local
and regional food systems may travel fewer miles and use less fossil fuel to
reach the consumer, one cannot assume that these systems are more energy
efficient compared to the conventional food system. The importance of
Life Cycle Assessment (LCA) cannot be overlooked when considering
transport-related fuel use and carbon dioxide emissions within the context of
the entire food system. Carbon dioxideequivalents per kilogram of tomato
were compared over a 20-year period for tomatoes grown in Denmark, the
Netherlands, Sweden (with Sweden being the end consumption point), and other
countries.[86]
Spanish tomatoes were shown to have lower CO2 equivalents than those
produced in Denmark, the Netherlands, and Sweden, even though the
transportation distances to Sweden were shorter than for the Spanish
tomatoes. The reason is that the Spanish tomatoes were raised in open
ground while the Swedish, Dutch, and Danish tomatoes were raised in heated
greenhouses, which required more fossil fuel energy in crop production.
Transportation energy savings for the systems with shorter transport distances
were overshadowed by higher energy needs in crop production. The results of
this Swedish study underscore the importance of examining fuel use and CO2
emissions across all sectors of the food system.
These actions are suggested to
better document the external costs of the current food system, reduce fuel use
and CO2 emissions from food transport, and to examine potential
benefits of more local and regional food systems:
· Buy local or regionally grown food whenever possible.
Several resources produced by the Iowa Department of Agriculture and Land
Stewardship, Practical Farmers of Iowa, and ISU Extension give Iowans
information on how and where to sell or purchase food through farmers markets,
community supported agriculture enterprises, direct sales, on-farm stores, and
institutional markets.[87] [88]
· Grow your own fruits and vegetables, and look for
opportunities to participate in community gardens.
· Plan effectively to minimize the number of shopping trips
you make to purchase food. Whenever possible, coordinate your trip to the
grocery store with your trip to the farmers market.
· Encourage grocery store managers and farmers market
managers to work together so that farmers markets can be held in or close to
the parking lots of grocery stores.
· Consult with nutritionists to encourage replacement of
foods with low nutrient value with more nutrient dense fresh foods that can be
easily grown in Iowa. For example, cabbage has more nutrients and can be
stored for longer time periods than lettuce.
· Pursue opportunities to market produce and meats locally
and regionally. These opportunities include direct marketing efforts and
cooperative supply networks. Groups such as Practical Farmers of Iowa and
the Iowa Network for Community Agriculture can provide information and
contacts.
· Diversify production and processing to meet the growing
demand for local food products.
· Research opportunities to add value to foods grown on Iowa
farms.
· Work with researchers on season-extending technologies for
fruits, vegetables, grains, and legumes, keeping in mind external environmental
and community costs.
· Work to locate farmers markets near grocery stores and
supermarkets. This would reduce consumer fuel usage and may increase business
for both groups.
· Conduct baseline research that compares conventional,
regional, and local food systems regarding fossil fuel energy used in all
sectors of the food system (production, processing, storage, transportation,
distribution).
· Compare energy efficiencies and greenhouse gas emissions
between truck and rail transport systems.
· Conduct baseline research to show whether increased use of
local and regional food systems in the United States would decrease the
ecological foot print.[89]
(The ecological footprint measures human impact on nature.)
· Begin pioneering research in Iowa on the use of Life Cycle
Assessments [90] [91] for
specific fresh and processed food items.
· Develop or create simple stories that can be understood by
consumers to explain the true price tag for each food item. Hidden
external environmental and community costs need to be documented and presented
to consumer groups. A set of educational materials entitled "Price
Tags, Cost Tags,"[92]
developed by the University of Wisconsin's Center for Integrated Agricultural
Systems, could serve as a model.
· Develop economic models that assign value to the external
environmental costs of our current food system and compare the same
environmental costs with regional or local food systems.
· Continue on-farm research on extending Iowa's fruit,
vegetable, legume, and grain production season, keeping in mind external
environmental and social costs.
· Conduct on-farm research on renewable alternative fuels for
food production, processing, and transport within local and regional food
systems.
· Require that national and state and local food policy
councils address energy efficiency of the food system in their work.
· Modify or eliminate state and federal rules that limit
commerce of local and regional food systems.
· Formulate policy that provides incentives and regulations
to develop new food labels that inform consumers on the relative level of
external environmental and community costs.
Sector
|
Average (percent) |
|
Production |
17.5 |
|
Processing |
28.1 |
|
Transportation |
11 |
|
Restaurants |
15.8 |
|
Home preparation |
25 |
|
|
|
|
Food system** |
15.6 |
* (Excerpted from Table 2,
"Energy Use in the Food System: A Summary of Existing Research and
Analysis." Center for Integrated Agricultural Systems, University of
Wisconsin-Madison.)