基于跨期排污权交易的最优环境监管策略

The Optimal Supervision Mechanism Based on Inter-temporal Emission Trading

政府有效监管是我国排污权交易市场顺利运行的一个关键因素。通过构建一个连续动态模型,讨论了跨期排污权交易条件下政府最优的环境监管策略,并对影响政府最优监管策略选择的因素展开进一步讨论。结论表明:企业选择不违法排放污染物时,政府应将监管水平设置在一个最低水平上,该监管水平受时间偏好率、排污税及补贴等因素影响,当时间偏好率较大时,政府最优监管水平应随时间呈先增加后不变趋势;当时间偏好率较小时,政府最优监管水平应随时间呈先减小后不变趋势;排污税及补贴水平越大,最优监管水平越高。企业违法排放污染物时,单纯依赖政府的监管并不能让企业守法排污,政府需选择一个合适的违法排污惩罚力度与监管相结合,并将跨期交易时长选在企业违法排污转折点处;此时,最优监管水平不仅受排污税和补贴水平的影响,还受违法排污惩罚力度和政府单位惩罚成本等因素的影响。

Government regulation is one of the key factors in emissions trading.By building a continuous dynamic model,this article discusses the optimal environmental regulation of government policy under the condition of inter-temporal emissions trading,and further discusses the factors that affect the government regulatory strategy choice.The results show that when firm refuses to choose illegal discharge,the government should set the supervision level at a minimum level,and the supervision level is influence by the rate of time preference,sewage,tax and subsidy factors.For instance,when polluters pay more attention to the current cost,the government＇s optimal level of regulation will increase first and then keep fixed over time.When polluters pay more attention to long-term costs,the government＇s optimal level of regulation will decrease first and then increase over time;The higher the pollution tax and subsidy level,the higher the optimal supervision level.When firm decides to accept illegal discharge,relying only on the government＇s regulation cannot force corporate law-abiding drainage,in fact,the government needs to determine a suitable illegal dredge penalties combined with regulation,and select inter-temporal trading hours at the place of illegal dredge turning point.At this point,the optimal level of regulation is not only influenced by the level of pollution taxes and subsidies,but also by illegal dredge penalties and government unit cost.