The Effectiveness of Voluntary Environmental Programs—A Policy at a Crossroads?

Voluntary environmental programs (VEPs) have been used as a policy tool in the United States since the early 1990s and come in many forms. Early assessments of VEPs targeting changes in production processes showed that industrial participants improved their environmental performance and VEPs were celebrated as a viable alternative to more traditional regulation. Recent analyses using more sophisticated techniques, however, paint a less favorable picture. On the one hand, firms appear willing to sign up to VEPs, and in some cases, participants may be able to create a shield against future losses in shareholder value. On the other hand, these VEPs targeting production processes appear not to generate significant pollution abatement. The latter finding is particularly disturbing and this article discusses various explanations, including institutional failure and participant motivations. Future research needs to focus on understanding the firm motivation to invest in production‐related pollution abatement under a VEP. For policymakers, the research offers a warning on the limited impact to date of VEPs targeting production processes. However, the multitude of other VEPs, such as those which target new product development and changing market demands, merit a closer look to determine the overall potential of VEPs to engender positive environmental change.     

Maintaining high fluid pressures in older sedimentary basins

High fluid pressures in old geologic basins, where the mechanisms that generate high fluid pressure have ceased to operate, pose the problem of how high fluid pressures are maintained through geologic time. Recent oil and gas exploration reveals that low permeability shales, the source beds for oil and gas, contain large quantities of gas that are now being exploited in many sedimentary basins in North America. No earlier analyses of how to maintain high fluid pressure in older sedimentary basins included a shale bed as a source of adsorbed gas; this is a new conceptual element that will fundamentally change the analysis. Such a large fluid source can compensate for a low rate of bleed off in a dynamic system. If the fluid source is large enough, as the gas within these shale source beds appears to be, there will no appreciable drop in pressure accompanying a low rate of leakage from the basin for long periods. For the dynamic school of basin analysts this may provide the missing piece in the puzzle, explaining how high fluid pressures are maintained for long periods of geologic time in a crust with finite, non-zero permeability. This is a hypothesis which needs to be tested by new basin analyses.     

The application of failure mode diagrams for exploring the roles of fluid pressure and stress states in controlling styles of fracture-controlled permeability enhancement in faults and shear zones

Permeability enhancement associated with deformation processes in faults and shear zones plays a key role in facilitating fluid redistribution between fluid reservoirs in the crust. Especially in high fluid flux hydrothermal systems, fracture-controlled permeability can be relatively short-lived, unless it is repeatedly regenerated by ongoing deformation. Failure mode diagrams in pore fluid factor and differential stress space, here termed λ–σ failure mode diagrams, provide a powerful tool for analysing how fluid pressure and stress states drive failure, associated permeability enhancement and vein styles during deformation in faults and shear zones. During fault-valve behaviour in the seismogenic regime, relative rates of recovery of pore fluid factor, differential stress and fault cohesive strength between rupture events impact on styles of veining and associated, fracture-controlled permeability enhancement in faults and shear zones. Examples of vein-rich fault zones are used to illustrate how constraints can be placed, not just on fluid pressure and stress states at failure, but also on the fluid pressurization and loading paths associated with failure and transitory permeability enhancement in faults and shear zones. This provides insights about when, during the fault-valve cycle, various types of veins can form. The use of failure mode diagrams also provides insights about the relative roles of optimally oriented faults and misoriented faults as hydraulically conductive structures. The analysis highlights the dynamics of competition between fluid pressures and loading rates in driving failure and repeated permeability regeneration in fracture-controlled, hydrothermal systems.     

Quantifying secondary migration efficiencies

Exploration success relies on properly risking the hydrocarbon system relevant for each prospect. Accurate risking of secondary migration efficiencies has been difficult due to lack of simple procedures that relate rock properties such as permeability and entry pressures to migration velocities, oil stringer heights and saturations. In order to achieve improved estimates of charge probabilities, equations for the secondary migration process are formulated based upon the Darcy flow and buoyancy conditions. An analytical solution of the formulated equations is shown, making it possible to construct charts for efficiently assessing the column height of secondary migration hydrocarbon stringers. The average oil (hydrocarbon) saturation of the migrating stringer can be computed, making it easy to compute the permeability related, secondary migration losses. Inputs to the chart are hydrocarbon flow‐rates and flow‐path width, hydrocarbon viscosity and density, carrier bed dip, permeability and entry pressures. Outputs are stringer heights, hydrocarbon saturation, relative permeability, migration velocities and migration losses. A procedure for including the new equations into existing basin scale fluid flow simulators is outlined and a Java applet for calculating the properties is described. The Java applet is useful for sensitivity studies, and can also be used to test results from basin simulators with the new migration efficiency equations. The analytical solution suggests that many published methods for calculating hydrocarbon migration in fluid flow simulators will over‐estimate hydrocarbon saturations and therefore losses. Calculated migration velocities will also be too low.     

Motivations for Voluntary Environmental Management

This article examines the motivations for firms to participate in voluntary environmental programs and to adopt environmental management practices using data gathered from a survey conducted in 2005 of facilities located in Oregon operating in six industrial sectors. It is one of the first studies of voluntary environmental management to include small‐, medium‐, and large‐sized facilities as well as to include both privately and publicly owned facilities. In particular, we examine the effects of both external factors such as regulatory, consumer, and investor pressures, and internal factors such as technical and resource capacity, in influencing voluntary environmental behavior. The intent is to describe potential influences that have implications for designing and implementing private and public policies that foster effective voluntary environmental management by firms. We find that larger facilities are more likely to participate in more voluntary environmental programs, but are likely to adopt more environmental management practices only if environmental issues are of significant concern to them. Presence of an R&D department stimulates the adoption of more environmental management practices, particularly if environmental issues are of significant concern to the facility, but does not have a statistically significant impact on participation in voluntary programs. We also find that while regulatory pressures are significant in motivating participation in voluntary programs and adoption of environmental management practices, competitive pressures are only important in motivating the former. Pressure from final good consumers or from investors in publicly traded facilities is not found to have a significant influence on voluntary environmental behavior of facilities in this study.     

Measured domestication rates in wild wheats and barley under primitive cultivation,and their archaeological implications

Man's (or, more probably, Woman's) first cereal crops were sown from seed gathered from wild stands, and it was in the course of cultivation that domestication occurred. Experiments in the measurement of domestication rates indicate that in wild-type crops of einkorn, emmer, and barley under primitive systems of husbandry: (a) domestication will occur only if they are harvested when partially or nearly ripe, using specific harvesting methods; (b) exposure to shifting cultivation may sometimes have been required; and (c) under these conditions, the crops could become completely domesticated within 200 years, and perhaps only 20–30 years, without any conscious selection. This paper (a) considers possible delays in the start of domestication due to early crops of wild-type cereals lacking domestic-types mutants; (b) examines the husbandry practices necessary for these mutants to enjoy any selective advantage; (c) considers the state of ripeness at harvest necessary for the crops to respond to these selective pressures; (d) outlines field measurements of the selective intensities arising from analogous husbandry practices applied experimentally to living wild-type crops; (e) summarizes a mathematical model which incorporates the measured selective intensities and other key variables and which describes the rate of increase in domestic-type mutants in early populations of wild-type cereals under specific combinations of primitive husbandry practices; (f) considers why very early cultivators should have used those husbandry methods which, we suggest, led unconsciously to the domestication of wild wheats and barley; and (g) considers whether these events are likely to leave archaeologically recognizable traces.     

Analysis of the role of fluids in causing fractures in the Spraberry Trend,Midland Basin

The Spraberry Formation in west‐central Texas is a highly fractured formation with both extension and shear fractures. At least two sets of natural fractures exist in two reservoir intervals. We have considered two possible origins for the fracturing: (i) high fluid pressure plus tectonic stress and (ii) tectonic stress at near‐hydrostatic fluid pressure. Reconstruction of geologic, thermal and hydrodynamic histories suggests that high fluid pressures probably did not occur during the basin’s history. To explore the second hypothesis, we developed and applied a calibrated, discrete‐element model of Spraberry strata to investigate whether weak Laramide compressional forces could cause fractures in the absence of high fluid pressures. Simulation results suggest that a mild compressional episode of geologically short duration may indeed have induced conjugate shear fractures.