简介：Whenwetrytoestimatefutureenvironmentalcostsresultingfromourcurrenteconomicactivities,weusuallycalculatethepresentvalueoftheconsequencesforourfuturegenerationsbyutilizingadiscountrateasastandardeconomicprocedure.Thepopularityofthisprocedureissolelysupportedbyitssimplicitywhichassumes:(1)aperfectfinancialmarketovereven100years,and(2)existenceofastabletimepreferencebetweentwoconsecutiveperiodsforanindividualconsumer.Anapparentdeficiencyofthisapproachisthatthepresentvalueoflifequalityoffuturegenerationsvariestoalargeextentalonganarbitrarilychosendiscountrate.Asamatteroffact,thediscountrate,whichcouldreflectthetimepreferenceas2%or5%,matterswhenwepredictcurrentstrategiesofenvironmentalprotectionforfuturegenerations.Simplyapplyingadiscountratetoevaluatethequalityofourfuturegeneration,withoutclarifyingtheactualproductionmechanismbehindthis,isalmosttothesameasignoringthefactthatallofthegoodsareproducedthroughanactualproductionprocessandthatenvironmentaldegradationreducestheefficiencyofthatprocess.Thegreatestconcernforourfuturegenerationsshouldnotbegivenbyanassumeddiscountrate,sincethediscountrateitselfisdeterminedbyfinancialmarketconditionsatcertainpointsintime.