Earth stewardship: Shaping a sustainable future through interacting policy and norm shifts

Transformation toward a sustainable future requires an earth stewardship approach to shift society from its current goal of increasing material wealth to a vision of sustaining built, natural, human, and social capital—equitably distributed across society, within and among nations. Widespread concern about earth’s current trajectory and support for actions that would foster more sustainable pathways suggests potential social tipping points in public demand for an earth stewardship vision. Here, we draw on empirical studies and theory to show that movement toward a stewardship vision can be facilitated by changes in either policy incentives or social norms. Our novel contribution is to point out that both norms and incentives must change and can do so interactively. This can be facilitated through leverage points and complementarities across policy areas, based on values, system design, and agency. Potential catalysts include novel democratic institutions and engagement of non-governmental actors, such as businesses, civic leaders, and social movements as agents for redistribution of power. Because no single intervention will transform the world, a key challenge is to align actions to be synergistic, persistent, and scalable.     

Simulating Unstressed Crop Development and Growth Using the Unified Plant Growth Model (UPGM)

Since initial development of the EPIC model in 1989, the EPIC plant growth component has been incorporated into other erosion and crop management models (e.g., WEPS, WEPP, SWAT, ALMANAC, and GPFARM) and subsequently modified to meet research objectives of the model developers. This has resulted in different versions of the same base plant growth component. The objectives of this study are the following: (1) describe the standalone Unified Plant Growth Model (UPGM), initially derived from the WEPS plant growth model, to be used for merging enhancements from other EPIC-based plant growth models; and (2) describe and evaluate new phenology, seedling emergence, and canopy height sub-models derived from the Phenology Modular Modeling System (PhenologyMMS V1.2) and incorporated into UPGM. A 6-year (2005–2010) irrigated maize (Zea mays L.) study from northeast Colorado was used to calibrate and evaluate UPGM running both the original (i.e., based on WEPS) and new phenology, seedling emergence, and canopy height sub-models. Model statistics indicated the new sub-models usually resulted in better simulation results than the original sub-models. For example when comparing original and new sub-models, respectively, for predicting canopy height, the root mean square error (RMSE) was 53.7 and 40.7 cm, index of agreement (d) was 0.84 and 0.92, relative error (RE) was 26.0 and ?1.26 %, and normalized objective function (NOF) was 0.47 and 0.33. The new sub-models predict leaf number (old sub-models do not), with mean values for 4 years of 2.43 leaves (RMSE), 0.78 (d), 18.38 % (RE), and 0.27 (NOF). Simulating grain yield, final above ground biomass, and harvest index showed little difference when running the original or new sub-models. Both the new phenology and seedling emergence sub-models respond to varying water deficits, increasing the robustness of UPGM for more diverse environmental conditions. Future research will continue working to incorporate existing enhancements from other EPIC-based plant growth models to unify them into one model such as multispecies competition and N cycling.     

Modeling the dispersion of drilling muds using the bblt model: the effects of settling velocity

The benthic boundary layer transport (bblt) model was widely used in the Atlantic Canadian offshore region to assess the potential impact zones from drilling wastes discharges from offshore oil and gas drilling. The current version of the bblt uses a single-class settling velocity scenario, which may affect its performance, as settling velocity is size, shape, and material dependent. In this study, the effects of settling velocity on bblt predictions were assessed by replacing this single-class settling velocity scenario with a multi-class size-dependent settling velocity scenario. The new scenario was used in a hypothetical study to simulate the dispersion of barite and fine-grained drilling cuttings. The study showed that the effects of settling velocity on bblt predictions are spatial, temporal, and material dependent.     

Structure and antioxidant activity of phenolic compounds isolated from the edible fruits and stem bark of Harpephyllum caffrum

Antioxidant activity in edible fruits is an important characteristic in the choice of fruits for human consumption, and has profound influence on nutrition and health. Two pharmacologically active triterpenoids, β-sitosterol and lupeol, and the powerful flavan-3-ol antioxidant, (+)-catechin, were isolated from the edible fruits of Harpephyllum caffrum while a mixture of cardanols, an alkyl p-coumaric acid ester, and (+)-catechin were isolated from the stem bark. This is the first report of these compounds being isolated from this plant. The antioxidant capacity of (+)-catechin was higher than the other isolated compounds as well as the known antioxidant, ascorbic acid.     

The Value of Monitoring for Radon in the Home: A Decision Analysis

In light of the recent publicity about the adverse health effects of radon gas, many citizens and government officials are considering whether or not to monitor for radon in homes. This paper presents a formal decision analysis of the monitoring dilemma from the perspective of hypothesized homeowners. The analysis considers the costs of radon monitoring and control, the carcinogenic risks of radon exposure, the demographics of household size, and a hypothetical homeowner's knowledge of radon exposure levels—with and without the benefit of specific monitoring data. Since monitoring every home in the United States would be quite expensive, the analysis reveals some more efficient monitoring strategies that might be employed by citizens and government officials. While the paper presents a new analytic perspective in the monitoring problem, the results should not be considered definitive. Further study is necessary to clarify precisely what is known about radon exposure, health effects, and control strategies.     

Overview of Proposed Air Emission Standards and Guidelines for Municipal Waste Combustors

The EPA proposed regulations for municipal waste combustors (MWCs) on December 20, 1989. The regulations include (1) performance standards under Section lll(b) of the Clean Air Act (CAA) for new, modified, or reconstructed MWCs and (2) draft emission guidelines and compliance schedules for the states to use to develop control requirements from existing MWCs under Section 111(d).

This paper will outline the proposed air emission standards and guidelines, as well as the basis for the prescribed emission limits. The schedule for the remainder of the regulations development will also be discussed.     

Summary of the 1991 EPRI/EPA/DOE SO2 Control Symposium

The 1991 SO₂ Control Symposium was held December 3-6, 1991, in Washington, D.C. The symposium, jointly sponsored by the Electric Power Research Institute (EPRI), the U.S. Environmental Protection Agency (EPA), and the U.S. Department of Energy (DOE), focused attention on recent improvements in conventional sulfur dioxide (SO₂) control technologies, emerging processes, and strategies for complying with the Clean Air Act Amendments of 1990. Its purpose was to provide a forum for the exchange of technical and regulatory information on SO₂ control technology. Over 800 representatives of 20 countries from government, academia, flue gas desulfurization (FGD) process suppliers, equipment manufacturers, engineering firms, and utilities attended. In all, 50 U.S. utilities and 10 utilities in other countries were represented. In 11 technical sessions, a diverse group of speakers presented 111 technical papers on development, operation, and commercialization of wet and dry FGD, Clean Coal Technologies, and combined sulfur dioxide/nitrogen oxides (SO₂/NO_x processes.     

Soil salinity,household wealth and food insecurity in tropical deltas: evidence from south-west coast of Bangladesh

As a creeping process, salinisation represents a significant long-term environmental risk in coastal and deltaic environments. Excess soil salinity may exacerbate existing risks of food insecurity in densely populated tropical deltas, which is likely to have a negative effect on human and ecological sustainability of these regions and beyond. This study focuses on the coastal regions of the Ganges–Brahmaputra delta in Bangladesh, and uses data from the 2010 Household Income and Expenditure Survey and the Soil Resource Development Institute to investigate the effect of soil salinity and wealth on household food security. The outcome variables are two widely used measures of food security: calorie availability and household expenditure on food items. The main explanatory variables tested include indicators of soil salinity and household-level socio-economic characteristics. The results of logistic regression show that in unadjusted models, soil salinisation has a significant negative effect on household food security. However, this impact becomes statistically insignificant when households’ wealth is taken into account. The results further suggest that education and remittance flows, but not gender or working status of the household head, are significant predictors of food insecurity in the study area. The findings indicate the need to focus scholarly and policy attention on reducing wealth inequalities in tropical deltas in the context of the global sustainable deltas initiative and the proposed Sustainable Development Goals.