廢棄物回收再利用、環境品質與社會效用之經濟分析

Recycling, Environment Quality, Consumption, and Social Welfare

魏國棟(Kwo-Dong Wey) ； 方振瑞(Cheng-Ray Feng) ； 鄭惠珍(Hui-Chen Cheng)

《農業與資源經濟》 8卷2期 (2014/12) Pp. 33-55

摘要

在生產與消費過程中，必然產生殘餘物質，在無法完全妥善處理下，會逐漸累積而使得生活環境品質日益惡化，加上台灣屬資源進口國家，故廢棄物的回收再生愈顯重要。本文以追求無窮期社會效用極大化為目標，建構動態最適化模型進行廢棄物回收再利用、環境品質及社會效用間的經濟性理論分析。分析結果發現，若代表性個人為改善環境品質所願意放棄的消費量愈多，反而將使消費成長率降低，而環境自淨能力提高，會對消費成長率產生負向影響。另外，經由提高回收率、增加再生料之生產，可減少因部分資源用於污染防治支出對消費與投資的負向影響。所以，若社會越重視環境品質，恆定狀態下之消費量與實體資本存量越高，廢棄物存量則越低，社會福利也會因而增加；時間偏好率愈高時，最適消費量、最適實體資本存量及最適社會福利水準皆會下降，同時最適廢棄物存量則會上升；原生料進口數量減少時，恆定狀態下之消費量與實體資本存量將會因總產出減少而下降。

關鍵字

廢棄物回收再利用 ； 環境品質 ； 社會效用 ； 動態最適化模型

並列摘要

This study employs the dynamic optimal control model to analyze the impacts of waste recycling on the social welfare. The solid wastes generate the negative social utility. However, the secondary materials, which are serving as the input of social production function, can be obtained through the wastes recycling. So, the waste recycling has positive effect on the social utility. Following the Ramsey rule in the previous studies, the optimal consumption growth rate was determined by the time preference rate and marginal productivity of capital. This paper concludes that the optimal consumption growth rate will increase when each consumer is willing to trade-off more consumption for better environmental quality. Besides, the higher self-cleaning rate of the nature will have negative effect of the optimal consumption growth rate. In addition, through the comparative static analysis, this study finds that the social welfare will increase when the society is more concerned the issue of environmental quality. But, the higher rate of time preference will cause the less social welfare. Therefore, the social welfare will be much better if the government not only encourages the industries to employ more recycled materials, but also promotes the people consciousness to protect the environmental quality.

並列關鍵字

recycling ； environment quality ； social welfare ； dynamic optimal control model