Bjoern Hagen

Cities increasingly recognize the importance of shade to reduce heat stress and adopt urban forestry plans with ambitious canopy goals. Yet, the implementation of tree and shade plans often faces maintenance, water use, and infrastructure challenges. Understanding the performance of natural and nonnatural shade is critical to support active shade management in the built environment. We conducted hourly transects in Tempe, Arizona, with the mobile human-biometeorological station MaRTy on hot summer days to quantify the efficacy of various shade types. We sampled sun-exposed reference locations and shade types grouped by urban form, lightweight/engineered shade, and tree species over multiple ground surfaces. We investigated shade performance during the day, at peak incoming solar, at peak air temperature, and after sunset using three thermal metrics: the difference between a shaded and sun-exposed location in air temperature (∆ T _a ), surface temperature (∆ T _s ), and mean radiant temperature (∆ T _MRT ). Air temperature did not vary significantly between shade groups, but ∆ T _MRT spanned a 50°C range across observations. At daytime, shade from urban form most effectively reduced T _s and T _MRT , followed by trees and lightweight structures. Shade from urban form performed differently with changing orientation. Tree shade performance varied widely; native and palm trees were least effective, while nonnative trees were most effective. All shade types exhibited heat retention (positive ∆ T _MRT ) after sunset. Based on the observations, we developed characteristic shade performance curves that will inform the City of Tempe’s design guidelines toward using “the right shade in the right place” and form the basis for the development of microclimate zones (MCSz).

There has been a recent upswing of academic interest in the social dimensions of sustainable cities, especially the dynamics of Quality of Life (QoL), Environmental Equity, Ecosystem Services, Eco-Friendliness, Public Engagement, and Well-Being and Happiness Indicators. These factors are only now being evaluated as critical aspects of sustainable place-making and community development. This paper explores the social dimensions of neighborhood development in what some believe to be one of the most sustainable cities—Freiberg, Germany. We look at two neighborhoods that were specifically designed and built with sustainability principles and practices at their core. The authors surveyed residents of these neighborhoods to measure their levels of well-being, satisfaction with place, and other important QoL factors. Quantitative data was ascertained from residents using a survey questionnaire. The results show a high correlation between QoL factors as a function of place-making and sustainability practice.

To broaden our understanding of global climate change (GCC), this article presents results from an ongoing longitudinal research project that investigates public GCC risk perceptions in nine countries focusing on different perceptions important in policy formulation. A key goal of the study is to understand which nations express similar or different viewpoints with respect to explanatory factors such as threat perceptions, hazard experience, socio-demographics, knowledge of climate change, and other factors found in the environmental hazards literature. Despite many variances in GCC perceptions among the surveyed national populations, the analysis shows that some differences are marginal, while others allow the grouping of countries based on different perception factors. Survey results reveal a high degree of uncertainty with regards to climate change dimensions including risk, science, knowledge, and policy approaches to mitigate GCC.