Close to 80% of people in the U.S. live and work in urban areas. Food systems serving these areas cause large impacts on the environment due to high population densities, heavy reliance on external food sources, and failure to recycle nutrients. Approaches to analyze these systems are challenging because of disconnects among processes used for production, distribution, consumption and cycling of food, energy and water needed to support people living in urban settings.

The overall goal of this project was to develop a framework for analysis of urban food, energy, and water as integrated systems for the Des Moines, Iowa metropolitan region and the city itself (representative of mid-sized cities in rainfed agricultural landscapes). Because experiments using large-scale manipulation of the landscape are not feasible, this was explored using models to simulate effects of changes in land use, farming practices and consumer behavior on the environment (water quality, global warming potential). Investigators developed a set of what ifs? to test policies and decisions leading to increases in local table food production to supply 50% of the local population’s diet. Follow-on effects of energy and water use and environmental impacts for the metropolitan region and the city itself were quantified.

The land required to produce 50% of local diets in 2050 was determined for the metropolitan region (six counties surrounding the city) and the city itself.  For the region, approximately 18,000 hectares (2.5% of land zoned for agriculture) would meet this criterion, for the city approximately 1,450 hectares (about 6.4% of land within city boundaries) would meet it (for both this excludes pasture area for livestock). Information from focus groups and surveys of local producers were used to develop an agent-based model to predict farmer choices for land allocation to table food production (currently only about 1,500 ha for the region). If combined increases in interactions among farmers, technical assistance for them, improved policies (insurance for table food crops, zoning changes) and markets were considered, the model suggests that allocations for table food could reach 20,000 hectares.

A life-cycle assessment model used alone to quantify global warming potential (GWP), energy use and water use associated with increased local table food production for the region indicated decreases (15% less for both GWP and energy use, 25% less for water use) from 2020 to 2050 compared to current conditions (more than 90% of table food is currently produced outside the region). These effects were due to more intensive production practices used in locations producing the majority of food currently (2020) consumed, as well as transportation and food waste.  A hydrological model used alone indicated that land area changes greater than 30% would be necessary for measurable decreases in flow volumes, nitrogen, sediment and phosphorus loads in stream water draining the area. Combined models allowed better estimation of future crop yields influenced by changing climate and indicated that predicted change in local table food production from 2020 through 2040 would lead to decreases in GWP, energy and water use on a per capita basis, followed by increases in all three between 2040 and 2050 for scenarios that led to the greatest land use allocation changes.

At the city scale, additional models were used to assess effects of changes in the landscape on urban building energy use. An urban expansion map described future configurations of buildings based on population growth estimates and combined with a climate model to predict future surface temperatures. A framework was developed for building energy use models that included effects on heat transfer due to surrounding microclimate features (trees, urban agriculture production areas) and to allow scaling models from individual buildings to neighborhood and whole-city scales. These models are being integrated with life-cycle assessment and hydrological models to generate integrated analysis of food-energy-water dynamics for the city.

Stakeholder engagement in the study area included a formal 15-member stakeholder advisory board that met two to three times per year (to advise on research approaches, interpretation/presentation of results), local participants in focus groups and interviews (producers, consumers and distributors of local foods), collaboration with local food aggregators/distributors, and consultation with members of organizations involved in local food systems in Des Moines and throughout Iowa.  Stakeholders and collaborators have used research results from the project to support development of their strategic plans, address local food issues in their climate adaptation and community resilience plans, and have included project personnel in conference and local presentations in support of local foods and food systems.

The project also provided workforce development for undergraduate (15), graduate (14) and postdoctoral (2) scholars who engaged in this interdisciplinary research together and with project faculty. Students who have graduated have been successful in obtaining post-doctoral appointments at universities in Europe and Asia, with prestigious national laboratories in the US, and as practitioners and researchers in private industry.

Last Modified: 04/30/2025
Modified by: Janette R Thompson