碳贸易中碳价格计算的土地机会成本模型评述及实例分析

碳价格的确定对于各类生态系统价值的估算及碳贸易具有重要的意义。碳价格是根据单位固碳量的固碳成本来确定的，而固碳成本的计算是确定碳价格中的难点，土地机会成本则是固碳成本计算中的一个重点方法。本文分析了在碳价格确定中存在的一些问题，介绍了目前在碳贸易中计算碳价格常用的3种土地机会成本的模型：自下而上模型（Bottom-up model）、部门模型（Sectoral model）和计量经济模型(Econometrical model)，并对这3种模型进行了比较和评述。结果表明，这3个模型均不适用于我国，特别是北方草原区的碳价格计算。为此，本文初步给出了一个在我国内蒙古草原区确定碳价格的固碳成本估算方法。

The Models of Land Opportunity Cost for CO2 Pricing in Carbon Trading: A Case Study in North China''''s Grassland

The development of the theory of carbon trading has been undergoing more than ten years,but the related research work of the C-trading in China has been limited.The price of carbon dioxide in C-trading was equal to the total amount of the CO_2 sequestration in a project divided by the costs of the project. It was rather a difficult process to estimate the costs of project.Moreover,the estimation of land opportunity cost as a part of the costs of project was particular hard to calculate.Presently,there are three popular models to calculate the land opportunity cost in C-trading,and they are bottom-up model,sector model and econometrical model.The three models are introduced and compared with each other in this article,and their suitability in China is assessed,especially in the northern grassland of China.In the end part,the method to calculate the carbon pricing of the grassland in Inner Mongolia of China was discussed as an example.As a comparison conclusion,the three models have their own excellences and shortcoming.The bottom-up model is much easier to understand and calculate,but it can not reflect the real wills of the landlords and the intricate relationships between the agriculture and forestry.The sector model can reflect the relationships between the agriculture and forestry well,but it is not yet considering the landlords' will.The econometrical model contains the information from the landowners,so it can predict the transformation track of the land.However,the model works on the private land,not the public land.Another drawback of sector and econometrical model is that it is too complicated to understand and compute.The judgment on the three models indicates that none of them is suitable to application in China,especially in the northern grassland of China because the environmental conditions in this zone are much different from those in the areas mentioned in the former studies.Finally,a new idea and a more suitable and feasible method has been brought forward to estimate the carbon price in this especial area.It is very important and meaningful to confirm the carbon price in the grassland of China.