Philip H. Byer

Methods for addressing climate change uncertainties in project environmental impact assessments

Climate change has important implications for assessing impacts of many types of project. If climate change is to be included in environmental assessments, then proponents must be able to incorporate its impacts and inherent uncertainties effectively into their analysis; many proponents do not possess sufficient grounding in how to accomplish this task successfully. In this paper, three basic analytical approaches to uncertainty analysis — scenario analysis, sensitivity analysis, and probabilistic analysis — are presented that proponents could use for integrating climate change induced impacts and their uncertainties into their environmental assessments, together with a framework for judging the circumstances that determine which method would be applicable. The use of these three approaches is illustrated on the environmental impacts of a run-of-the-river hydroelectric project.

Household, hotel and market waste audits for composting in Vietnam and Laos

In Da Nang and Ha Long, Vietnam and in Vientiane, Laos, there was interest by local authorities in separating and composting waste in order to reduce environmental and health problems at the local landfills and to produce a soil conditioner for local agricultural use. To assist in the planning of composting projects, three studies were carried out to estimate waste quantities and composition. 1. A 9-day audit of waste from 45 vendors in a market in Vientiane, the capital of Laos. The total quantity of waste and the quantity in each of nine categories were estimated for each of six different types of vendors. 2. A 7-day audit of waste disposed by three hotels in the tourist area of Ha Long, Vietnam. Waste quantities were estimated in total, on a per guest basis, and in three main categories: compostables, recyclables and miscellaneous. 3. A 7-day audit of waste collected from 74 households in Da Nang, the fourth largest city in Vietnam. Waste from each household was separated into compostable and non-compostable waste. Over 60% of each waste source comprised compostable waste and this was considered significant enough to warrant further planning of composting operations.

Use of knowledge-based systems for the review of environmental impact assessments

Environmental impact assessments (EIA) have the potential for improving public decisions affecting environmental quality. Such assessments facilitate rationality, comprehensiveness, accountability, and public participation in the decision-making process. However, many reviews of the environmental assessment process show that EIA are often carried out in an adhoc and methodologically unsound way (Rosenberg, et al., 1981; Nichols and Hyman, 1982; Whitney and Maclaren, 1985). Too often, this results in questionable documents that merely attempt to rationalize and justify decisions not made with due concern for the environment.

Bias-by-selection: The accuracy of an unbiased estimator

In a previous paper, a method for the elimination of bias-by-selection from before-and-after comparisons has been suggested. While the suggested estimator is unbiased, there is reason to be concerned about its precision. In this paper expressions are obtained for the variance of the unbiased estimator and the mean square error of the commonly used biased estimator. Their comparison yields conditions under which the unbiased has the smaller error. It is also shown that the sum of unbiased estimators for n sites is asymptotically normally distributed. The use of this information for significance tests and the determination of confidence limits is illustrated.

ADDRESSING AND COMMUNICATING CLIMATE CHANGE AND ITS UNCERTAINTIES IN PROJECT ENVIRONMENTAL IMPACT ASSESSMENTS

While climate change has become an important concern at both regional and global levels, its inherent uncertainties have often been cited as the main reason for delaying many actions to mitigate its potential impacts. Reviews of environmental assessments (EAs) have shown that impacts from climate change have been inadequately addressed within them and that the corresponding uncertainties have been addressed even more poorly. This paper describes several basic approaches for addressing and analysing climate change within the EAs of individual projects with a focus on its uncertainties. Subsequently, the paper describes how the results from this analysis can be effectively and comprehensively communicated to the EAs disparate set of technical and non-technical decision-makers and stakeholders. Based upon this overall approach, the paper proposes a general set of guidelines that enables proponents to incorporate climate change and its uncertainties into project EAs.

Moisture control during landfill operation

During the operation of a landfill, significant quantities of moisture may infiltrate the facility, with the infiltration volume dependent upon both soil cover design and operational practices. A simulation model has been developed to represent the construction of a landfill and the associated moisture control options. Modelling results show that stochastic rather than average precipitation inputs should be considered. Cell building pattern and snow removal are shown to be operational variables that potentially have a significant impact upon moisture content buildup within a landfill facility.

A fuzzy screening model for multiple attribute decision-making

Abstract A method for the screening of multiple attribute decision-making problems is presented. The model assists the decision-maker in eliminating inferior alternatives and insignificant attributes prior to a detailed evaluation. A preliminary evaluation of the alternatives provides the information necessary for the reduction of the decision problem. The procedure calculates maximum preference factors on which the decision-maker can base his screening decisions. These factors assess the role of alternatives in the final ranking by estimating their potential to become superior to other alternatives. Since screening tasks are carried out early in decision-making, the information available is generally uncertain. Uncertainty is represented in the model using fuzzy sets. This framework permits the handling of both imprecise and precise (crisp) estimates of impacts and provides a possibil-istic assessment of the risk associated with screening decisions.

Adaptation, flexibility and project decision-making with climate change uncertainties

Project planning in the future must directly address both climate change and uncertainties about it. This paper presents the use of classical decision criteria, such as maximin and minimax regret, and approaches for adapting to climate change given the uncertainties. Adaptation strategies can help reduce the effects of uncertainties by allowing for adjustments in designs as the future climate evolves, although at a cost for such future flexibility. Adding such options and evaluating them against other design options using the decision criteria can provide valuable information to decision-makers and other stakeholders during project planning. A hypothetical example of a hydroelectric project illustrates the use of these approaches.

A SCREENING MODEL FOR THE SELECTION OF EVALUATION TECHNIQUES FOR LARGE-SCALE SYSTEMS

There are many techniques available to the systems analyst to evaluate alternative system plans and designs. The analyst faces the problem of choosing the evaluation technique most suited to the problem at hand. A discussion and methodology are presented to help the analyst make this choice. It is based upon making appropriate assumptions about the problem and choosing the technique that can incorporate these assumptions into the evaluation. A taxonomy of the techniques, based upon their abilities to consider specific types of assumptions, is presented. The basis for making appropriate assumptions is also discussed. The use of screening models to help make these choices is introduced. Two related models for helping analysts screen system attributes and uncertainties are presented. Their application to an analysis of building codes for protection against seismic activity illustrates their usefulness and their implications for the choice of evaluation techniques.

Modelling the cost-effectiveness of sanitary landfill leachate control systems

Abstract Leachate leakage is a major risk associated with sanitary and hazardous waste landfills. This paper describes how two simple performance models, time to breakthrough and leachate leakage flux, can be used in conjunction with a cost model to develop cost-effectiveness relationships which can be used to assist the leachate control system design and planning decision-making process, and, thereby, reduce this risk. Sensitivity and marginal analyses indicate that time to breakthrough (tb) is most sensitive to liner hydraulic conductivity and thickness and that increasing liner thickness yields increasing marginal returns to fb. Leachate leakage flux (qL) is sensitive to liner hydraulic conductivity and the leachate collection pipe spacing-liner thickness ratio. For a given pipe spacing, increasing liner thickness yields decreasing marginal returns to qL. Hypothetical cost-effectiveness relationships for tb and qL are developed analytically and numerically. As a means of introducing the concept of risk...