环境政策与经济绩效——基于污染的健康效应视角

Environmental policy and economic performance: a perspective of the health effects of pollution

文章基于环境污染的健康效应的视角,通过考察环境污染对居民健康的负面影响,进而经由健康水平影响有效劳动、经济产出及福利水平的作用机制,在一个扩展的Ramsey模型中探讨了环境污染、健康人力资本与经济增长之间的动态关系,运用数值模拟的方法对模型的稳态特征做了比较静态分析和政策影响分析。研究表明:(1)代表性个人的"时间偏好率"直接影响着经济的动态行为与长期特征;(2)当考虑污染的健康效应时,环境政策与均衡产出和福利水平分别呈不完全相同的倒"U"型关系。具体来看,在"时间偏好率"非常大(即,主要关注当前财富价值,较少关注未来财富价值)的经济体中,增加环境治理投资可能会挤占物资资本积累,然而健康状态不被重视,这是因为此时健康人力资本水平主要由消费水平而不是健康支出决定;而在"时间偏好率"非常小的经济体中,增加环境投资和健康投资都不会挤占物质资本积累,此时健康人力资本水平主要由健康支出而不是消费水平决定。再者,基于环境投资目的的"环境税"会对与健康人力资本相关的参数变化产生反应,会显著影响"最优环境税"和每一环境税所对应的均衡产出与福利水平。文章的经济学含义以及政策启示在于:政府在制定环境政策时,面对着"环境污染→社会成员健康水平→人力资本的有效劳动→经济产出""环境投资(环境税)→物质资本投资→经济产出"的双重影响关系,亦即,面临"经济产出"与"社会福利"的权衡,最终的权衡决策取决于决策者所代表主体的"时间偏好率"。

This paper studies the relationship between environmental pollution,health human capital and economic growth in an extended Ramsey model with assumption that the main consequence of pollution is the deterioration of individuals’health and the effective labor is determined by the health of the workers.And then it applies the numerical simulation method to analyze comparative statics and environmental policy effect.The paper findings indicate that:first,individuals’subjective rate of time preference directly affects the dynamic and long-term characteristics of the economy.Second,when considering the health effects of pollution,environmental policies and equilibrium output and social welfare are not exactly the same inverted‘U’relationship.Specifically,in an economy with the high rate of time preference,which pays more concern to the current value of wealth while less concern to the value of future wealth,increasing environmental investment will squeeze out the accumulation of material capital,but the health status has not been paid attention to;this is because health human capital is mainly determined by consumption level rather than health expenditure.In an economy with a very small time preference rate,increasing environmental investment and health investment will not expropriate physical capital accumulation.At this time,health human capital is mainly determined by health expenditure rather than consumption.Furthermore,the environmental tax for environmental investment purposes will respond to changes in parameters related to health human capital,which will significantly affect the optimal environmental tax and the level of welfare corresponding to each of the environmental tax.The study has such important implication:when developing environmental policies,government faces the trade-off between economic output and social welfare,which depends on the decision-maker’subjective rate of time preference on behalf of individuals.