Better methods are necessary to fully account for anthropogenic impacts on ecosystems and the essential services provided by ecosystems that sustain human life. Current methods for assessing sustainability, such as life cycle assessment (LCA), typically focus on easily quantifiable indicators such as air emissions with no accounting for the essential ecosystem benefits that support human or industrial processes. For this reason, more comprehensive, transparent, and robust methods are necessary for holistic understanding of urban technosphere and ecosphere systems, including their interfaces. Incorporating ecosystem service indicators into LCA is an important step in spanning this knowledge gap.

For urban systems, many built environment processes have been investigated but need to be expanded with life cycle assessment for understanding ecosphere impacts. To pilot these new methods, a material inventory of the building infrastructure of Phoenix, Arizona can be coupled with LCA to gain perspective on the impacts assessment for built structures in Phoenix. This inventory will identify the origins of materials stocks, and the solid and air emissions waste associated with their raw material extraction, processing, and construction and identify key areas of future research necessary to fully account for ecosystem services in urban sustainability assessments. Based on this preliminary study, the ecosystem service impacts of metropolitan Phoenix stretch far beyond the county boundaries. A life cycle accounting of the Phoenix’s embedded building materials will inform policy and decision makers, assist with community education, and inform the urban sustainability community of consequences.

Hemcrete is an alternative, environmentally‐friendly building material gaining adherents in Great Britain and other European countries. It is an attractive choice as a building material because it is made from a renewable resource, hemp, a hardy plant that is a close, but non‐hallucinogenic relative of marijuana. This plant is relatively easy to cultivate, requires little in the way of pesticides or fertilizers, and almost all parts can be used for various products from paper to textiles to food.

Hemcrete is made from a mixture of lime, water, and the fibrous outer portion of the hemp plant called the “hurd” or “shive”. When mixed, it is worked and placed much like conventional concrete ‐ hence the name. However, that is where the similarities with concrete end. Hemcrete is not comparable to concrete on a strength basis, and is better described as an alternative insulation product. When built into walls of sufficient thickness, Hemcrete offers high thermal efficiency, and has strong claims to being carbon negative. The purpose of this study
was to evaluate this claim of carbon negativity, and to compare these environmentally friendly qualities against conventional fiberglass batt insulation.

Our model was constructed using two identically sized “walls” measuring eight feet square by one foot in depth, one insulated using Hemcrete, and the other using fiberglass. Our study focused on three areas: water usage, cost, and carbon dioxide emissions. We chose water
usage because we wanted to determine the feasibility of using Hemcrete in the Phoenix metropolitan region where water is a troubled resource. Secondly, we wished to evaluate the claim on carbon negativity, so CO2 equivalents throughout the production process were measured. Finally, we wished to know whether Hemcrete could compete on a cost basis with more conventional insulation methods, so we also built in a price comparison.

Since the cultivation of hemp is currently unlawful in the United States, this study can help determine whether these restrictions should be relaxed in order to allow the construction of buildings insulated with Hemcrete.