Jane C. Powell’s research while affiliated with University of East Anglia and other places

Making choices on the basis of environmental assessment techniques such as life cycle analysis (LCA) requires a valuation of the impacts. A mature approach for doing this is economic valuation in which money values are ascribed to environmental and social costs associated with alternative products, processes or policies. In this chapter economic valuation is applied to a case study of waste management options including landfilling, incineration and recycling. The results show that the environmental costs of waste management options are specific to location, technology and material. Recycling is shown to be clearly beneficial in most cases.

The cycad Cycas armstrongii is endemic to the north-western corner of the Northern Territory in Australia. Here we provide data on its life history and population structure from four populations across its range. Few plants reproduced before they were 1 m in height. There was considerable variation in the proportion of reproductive plants between sites and years, but the sex ratio in all populations was close to 1:1. The growth rate of plants was approximately 4.5 cm year−1 which indicates that most plants are less than 100 years old and that the tallest individuals are likely to be little older than this. The annual fecundity of female plants ranged from 12 to 80 seeds; there was no evidence that fecundity varied with plant height. Dispersal was restricted generally to less than 1 m and the distribution of dispersal distances was fitted well by a gamma distribution. Recruitment occurred through both seedlings and vegetative sprouts and the proportion of juveniles (plants without trunks) in the populations varied between one-quarter and two-thirds. The data indicate that recruitment is episodic, but occurs more frequently under the current fire regime than amongst the canopy trees. It is shown that there is considerable variation in the dynamics of populations between sites and that the long term dynamics of a population cannot readily be inferred from an examination of the size structure at a single point in time.

One of the major problems with the future development of lifecycle assessment is the difficulty in converting lifecycle inventory results into environmental impacts, owing to problems associated with the interpretation and weighting of the data. The four main valuation approaches: distance-to-target, environmental control costs, environmental damage costs and scoring approaches are assessed and the individual methodologies evaluated. In conclusion it is considered that in a country which has clear, up-to-date, politically acceptable emission standards, a distance-to-target valuation system maybe acceptable. However, these circumstances are likely to be rare, and the choice of standards arbitrary and not scientifically based. Therefore a better choice is probably environmental damage costs, provided suitable economic damage figures are available.

Until recently the disposal option for municipal waste was selected purely on the grounds of financial effectiveness, but now with an increased concern for the environment other criteria such as resource use and environmental impact must also be taken into consideration. The incorporation of a range of different criteria into the decision making process is, however, a formidable task. One potential solution is to use multicriteria evaluation which provides for a systematic appraisal of a number of alternative projects on the basis of a series of criteria. In this study the multicriteria evaluation of six waste disposal options (landfill, incineration and refuse-derived fuel (RDF), each with and without recycling) resulted in RDF with recycling coming out as the best option under a variety of weighting scenarios. Only when a high weighting was put on cost criterion did landfill become the better option.

Recycling is widely assumed to be environmentally beneficial, although the collection, sorting and processing of materials into new products also entails significant environmental impacts. This study compares the relative environmental impacts of a recycling system (incorporating the kerbside collection of recyclable materials and their subsequent use by manufacturers), with a waste disposal system (in which the waste is disposed to landfill and primary raw materials are used in manufacture), using the technique of lifecycle assessment. The methodology is then extended to incorporate an economic evaluation of the environmental impacts. This combination of lifecycle assessment and economic evaluation can be termed ‘Lifecycle Evaluation’. Lifecycle assessment quantifies and evaluates the environmental impacts of a product from the acquisition of raw materials, through manufacture and use, to final disposal. Lifecycle assessment can also provide a framework for the analysis of environmental impacts from systems such as transport, or waste management, as demonstrated in this paper. The results, for a case study of Milton Keynes in Central England, show that the recycling system generally performs better than the waste disposal system in terms of contribution to global warming, acidification effects and nutrification of surface water. An alternative method of analysis is then used, in which an economic valuation of the environmental impacts is carried out. This produces net benefits for recycling, per tonne of material, of £1769 for aluminium, £238 for steel, £226 for paper and £188 for glass, and net costs of £2.57 for high density polyethylene (HDPE), £4.10 for poly (vinyl chloride) (PVC) and £7.28 for poly (ethylene terephthalate) (PET). It is concluded that lifecycle evaluation, the combination of lifecycle assessment and economic valuation, can be applied to a variety of waste management issues such as the appraisal of alternative methods of collection for recycling or an examination of the UK waste management hierarchy. This technique allows impacts to be expressed in homogenous units, and the inclusion of social and environmental impacts that would not normally be addressed within a lifecycle assessment. The approach would also facilitate the evaluation of environmental and social effects at a local level, which are particularly crucial to the success of community recycling schemes. Lifecycle evaluation could provide a powerful tool to aid the development of sustainable waste management and recycling policy.

The financial costs of recycling schemes fail to account for external costs and benefits such as environmental pollution, road congestion and accidents. This paper compares the environmental and social impacts of a kerbside collection scheme for recyclable household waste, with a bring scheme, using lifecycle assessment. Economic valuation is used to assign relative weights to these impacts. A second comparison examines the relative external costs of recycling and landfill disposal of waste. The results show that the kerbside collection scheme has a lower external cost than the bring scheme, but this is of less importance than the benefits to be gained within the manufacturing system by using secondary materials. It is concluded that the combination of lifecycle assessment and economic valuation is an effective means of evaluation to direct the sustainable development of waste management.

Waste disposal options are often prices at levels which fail to reflect their full social cost, resulting in an over-reliance on landfill disposal. The UK Government is now advocating a more sustainable approach to waste management, by promoting the waste management hierarchy, setting recylcing targets and introducing recycling credits. The Waste Mangement Strategy endorses the use of market-based instruments to correct for market failure and influence behaviour in the direction of sustainable waste management. The Landfill Tax, initially announced in November 1994, arose after a period of research into the use of economic instruments to internalise the externalities associated with landfill disposal. The initial proposal was for an ad valorem tax of 30-50% on the disposal price paid, administered by HM Customs and Excise. The tax was not intended to increase overall business costs, and is partially offset by a reduction in employers' National Insurance contributions. Limited tax rebates can also be made by making payments to proposed Environmental Trusts. These nonprofit making bodies will receive voluntary payments from landfill site operators and disburse the funds to various approved projects. The ensuing debate in the consultation period centre around the economic and environmental implications and of an ad valorem tax versus a weight-based tax, and in the Budget of 1995, it was the latter which was adopted, a move welcomed by most of the respondents to the consultation paper. The tax has been set at a standard rate of £7.00 per tonne; £2 per tonne for 'inactive' waste.

1 A computer simulation model is developed to examine the effects of varying levels of seedling recruitment, mortality and rates of clonal growth on genet diversity in populations of the clonal perennial herb, Ranunculus repens. 2 It is shown, following an initial colonization event, that there is a rapid loss of genets from populations in which there is no further seedling recruitment, and that such populations become dominated by a few large clones. Nevertheless coexistence of a high density of genets is possible in the short term in the nonequilibrium situation occurring immediately after a large scale disturbance. 3 The input of only a few seedlings each year into a population of ramets accelerates the loss of founder genets but acts as a powerful mechanism for maintaining genet diversity in populations. Varying the level of density-dependent mortality and the rate of clonal growth also influences genet diversity. 4 Taking the results of all the simulations together it is demonstrated that it is the ratio of seedling to ramet recruits that is crucial in determining the genetic architecture of clonal plant populations both in terms of the number and size hierarchy of genets. Significant variation in the relationship between population structure and the ratio of seedling to ramet recruits was related primarily to low initial population densities and subsequent low seedling inputs. 5 The low ratio of seedling to ramet recruits observed in many plant populations where seedling recruitment occurs within established populations is shown to be sufficient to maintain quite high genet densities relative to the total number of ramets, unless there is strong competition between genets. 6 Inequality in the genet size of clonal plants increases with time and also with a decrease in the ratio of seedling to ramet recruits, except at very low values where there is again a decrease in inequality. The development of genet size hierarchies in clonal plants is compared with that of aclonal plants.