ABSTRACT

Understanding complex and adaptive socio-ecological systems (SES) to deal with our most challenging and overlapping problems such as global climate change, biodiversity loss, and rising consumption rates requires sustainability theory that is commensurate with these problems’ size and complexity. The received United Nations-based sustainability framework aims to achieve a balance among three pillars—economics, environment, and social equity—for today and for future generations. Yet, despite applying this sustainability framework for over a quarter of a century, the Earth is less sustainable, not more. Theoretical trade-offs between environmental conservation and economic growth have often reinforced business-as-usual practices and educational paradigms, and emphasized economic values over ecological limits.

How can the principles of foundational naturalists help clarify, enhance, and advance sustainability discourse? I propose that the principles of Henry David Thoreau (1817-1862), Aldo Leopold (1887-1948), Rachel Carson (1907-1964), and Edward O. Wilson (1927-), express a worldview that captures and integrates a range and depth of historical, normative, economic, ecological, scientific, and social values for a viable and applicable discourse of sustainability.

This analytical study relies on (i.) textual analysis and interpretation of four key naturalists and humanists, (ii.) analysis of secondary sources that illuminate their proto- ecological and sustainability principles, and (iii.) interviews with leading sustainability scholars. Because these thinkers integrate science and ethics, natural history and philosophy, ecology and society, and environmental and economic problems within a holistic worldview, I call them systems naturalists. Their transdisciplinary worldview of one holistic system, with economics subordinated to environmental limits, links important values from the natural sciences and the humanities. The writings and examples of systems naturalists provide more robust historical sustainability principles that can help solve our most challenging SES problems by synthesizing a broad range of knowledge in the sciences, social sciences, and the humanities to inform sustainability paradigm, practices, and pedagogy.

In recent years environmental life-cycle assessments (LCA) have been increasingly used to support planning and development of sustainable infrastructure. This study demonstrates the application of LCA to estimate embedded energy use and greenhouse gas (GHG) emissions related to materials manufacturing and construction processes for low and high density single-family neighborhoods typically found in the Southwest. The LCA analysis presented in this study includes the assessment of more than 8,500 single family detached units, and 130 miles of related roadway infrastructure. The study estimates embedded and GHG emissions as a function of building size (1,500 - 3000 square feet), number of stories (1 or 2), and exterior wall material composition (stucco, brick, block, wood), roof material composition (clay tile, cement tile, asphalt shingles, built up), and as a function of roadway typology per mile (asphalt local residential roads, collectors, arterials). While a hybrid economic input-out life-cycle assessment is applied to estimate the energy and GHG emissions impacts of the residential units, the PaLATE tool is applied to determine the environmental effects of pavements and roads. The results indicate that low density single family neighborhoods are 2 - 2.5 X more energy and GHG intensive, per residential dwelling (unit) built, than high density residential neighborhoods. This relationship holds regardless of whether the functional unit is per acre or per capita. The results also indicate that a typical low density neighborhood (less than 2 dwellings per acre) requires 78 percent more energy and resource in roadway infrastructure per residential unit than a traditional small lot high density (more than 6 dwelling per acre). Also, this study shows that new master planned communities tend to be more energy intensive than traditional non master planned residential developments.