Envisioning a metropolitan foodshed: potential environmental consequences of increasing food-crop production around Chicago
Esther Bowen and Pamela Martin
2009 AGU abstracts
Abstract: Nationwide, cities are increasingly developing policies aimed at greater sustainability, particularly focusing on reducing environmental impact. Such policies commonly emphasize more efficiently using energy to decrease the greenhouse gas (GHG) footprint of the city. However, most plans ignore the food system as a factor in regional energy use and GHG emissions. Yet, the food system in the United States accounts for ~20% of per capita greenhouse gas emissions. Local, sustainable food production is cited as one strategy for mitigating GHG emissions of large metropolitan areas. “Sustainable” for regional agriculture is often identified as small-scale, diversified food crop production using best practices management. Localized food production (termed “foodshed”) using sustainable agriculture could mitigate climate change in multiple ways: (1) energy and therefore CO2-intensive portions of the conventional food system might be replaced by local, lower-input food production resulting in carbon offsets; (2) increased regional carbon storage might result from well-managed food crop production vs. commodity crop production; and (3) averted N2O emissions might result from closing nutrient cycles on agricultural lands following changes in management practices. The broader implications for environmental impact of widespread conversion to sustainable food crop agriculture, however, remain largely unknown. We examine the Chicago metropolitan region to quantify the impact of increased local food production on regional energy efficiency and GHG emissions. Geospatial analysis is used to quantify the resource potential for establishing a Chicago metropolitan foodshed. A regional foodshed is defined by minimizing cost through transportation mode (road, rail, or water) and maximizing the production potential of different soil types. Simple biogeochemical modeling is used to predict changes in N2O emissions and nutrient flows following changes in land management practices. Ultimately, quantification of impacts from changes in regional land use can inform regional planning for climate change mitigation strategies.
Effort Optimization in Minimizing Food Related Greenhouse Gas Emissions, a look at "Organic" and "Local"
Esther Bowen, Pamela Martin and Gidon Eshel
2008 AGU abstracts
Abstract: The adverse environmental effects, especially energy use and resultant GHG emissions, of food production and consumption are becoming more widely appreciated and increasingly well documented. Our insights into the thorny problem of how to mitigate some of those effects, however, are far less evolved. Two of the most commonly advocated strategies are "organic" and "local", referring, respectively, to growing food without major inputs of fossil fuel based synthetic fertilizers and pesticides and to food consumption near its agricultural origin. Indeed, both agrochemical manufacture and transportation of produce to market make up a significant percentage of energy use in agriculture. While there can be unique environmental benefits to each strategy, "organic" and "local" each may potentially result in energy and emissions savings relative to conventionally grown produce. Here, we quantify the potential energy and greenhouse gas emissions savings associated with "organic" and "local". We take note of energy use and actual GHG costs of the major synthetic fertilizers and transportation by various modes routinely employed in agricultural distribution chains, and compare them for ~35 frequently consumed nutritional mainstays. We present new, current, lower-bound energy and greenhouse gas efficiency estimates for these items and compare energy consumption and GHG emissions incurred during producing those food items to consumption and emissions resulting from transporting them, considering travel distances ranging from local to continental and transportation modes ranging from (most efficient) rail to (least efficient) air. In performing those calculations, we demonstrate the environmental superiority of either local or organic over conventional foods, and illuminate the complexities involved in entertaining the timely yet currently unanswered, and previously unanswerable, question of "Which is Environmentally Superior, Organic or Local?". More broadly, we put forth a database that amounts to a general blueprint for rigorous comparative evaluation of any competing diets.
Assessing Sustainability in the University of Chicago Dining Halls: Food, Energy and Greenhouse Gas Emissions
Esther Bowen and Pamela Martin
2008 AASHE abstracts
Sustainability proponents are increasingly calling on academic institutions to render their food procurement practices more sustainable. "Locally produced" and "organic" are currently the only two available sustainable options, with availability widely variable in space and time. However, as we show, no universally applicable generalization exists regarding which of those two models is more "sustainable." Here, we use the University of Chicago dining services and a single environmental metric, carbon dioxide emissions, as a case study quantitatively comparing the above competing "sustainability" models. We estimate the emissions of local and organic options for 54 produce items served in the University of Chicago dining halls. Our estimates of emission savings associated with organic versus conventional production are narrowly defined as carbon emissions associated with manufacturing fertilizers and pesticides customarily used in conventional production for each item. Similarly, we define averted emissions associated with local food as emissions that can be reasonably attributed to transportation of the food item from its origin to Chicago, accounting for both mode and distance. For each produce item, emissions savings are compared between local and organic production. Based on this comparison, incurring larger transportation distances to source organically results in emissions savings for some items (e.g. tomatoes, summer squash) but not for others (e.g. carrots, potatoes) and suggests that purchasing changes at the University would lead to reduced emissions. We present an equation for calculating emissions savings per dollar per kg to evaluate tradeoffs between cost and reduced carbon impact, allowing administrators to make informed policy decisions.