Some but not all U.S. metro areas could grow all the
food they need locally, according to a new study estimating the degree to which
the American food supply could be localized based on population, geography, and
diet.
The modeling study, led by Christian Peters at the
Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy Gerald
J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts
University, is published today in Environmental Science & Technology.
The model estimates whether 378 metropolitan areas
could meet their food needs from local agricultural land located within 250
kilometers (155 miles). Local potential was estimated based on seven different
diets, including the current typical American diet.
The results suggest:
* Metro centers in the Northwest and interior of the
country have the greatest potential for localization.
* Large portions of the population along the Eastern
Seaboard and the southwest corner of the U.S. would have the least potential
for localization.
* Surplus land existed under all diet scenarios,
raising questions about the best use of land for meeting health, environmental,
and economic goals.
"Not everyone lives near enough agricultural land
to have an entirely local or even regional food supply. Most cities along the
Eastern Seaboard and in the southwest corner of the U.S. could not meet their
food needs locally, even if every available acre of agricultural land was used
for local food production. Yet, many cities in the rest of the country are
surrounded by ample land to support local and regional food systems," said
Peters, senior author and associate professor at the Friedman School, whose
research focuses on sustainability science.
Peters and his team also modeled seven different diets
to estimate whether dietary changes could make a difference in the potential to
produce enough food for a metro area. The diets ranged from the current typical
American diet, which is high in meat, to vegan. Reducing animal products in the
diet increased the potential to produce all food locally, up to a point. Diets
with less than half the current consumption of meat supported similar levels of
localization potential, whether omnivore or vegetarian. Consumption of meat
(beef, pork, chicken and turkey) for the baseline typical American diet was
estimated at roughly five ounces per day.
"There would be different ways to do it. Imagine,
if we cut back to fewer than two and a half ounces per day by serving smaller
portions of meat and replacing some meat-centric entrees with plant-based
alternatives, like lentils, beans and nuts. More diverse sources of protein
could open new possibilities for local food. Nutrition research tells us that
there could be some health benefits, too," said corresponding author Julie
Kurtz, who was a master's degree student at the Friedman School at the time of
the study.
Under all the diet scenarios, the model projected the
United States having a surplus of land for meeting domestic food needs. In the
current American agricultural system, some farmland is used for biofuels and
export crops. The researchers point out that if metro centers focused on eating
locally, many agricultural areas would face new questions about local land use
priorities.
"It would be important to make sure policies for
supporting local or regional food production benefit conservation and create
opportunities for farmers to adopt more sustainable practices. Policies should
also recognize the capacity of the natural resources in a given locale or
region -- and consider the supply chain, including capacity for food processing
and storage," Peters said.
Economic efficiency for food production was beyond the
scope of the analysis. Also, the study is based on current conditions and does
not consider how future climate change may affect future agricultural
potential.
Story Source:
Materials provided by Tufts University, Health
Sciences