Co-benefits of CO_2-reducing policies in China-a matter of scale?

摘要

Acknowledgement of potential co-benefits-i.e.positive side-effects-of greenhouse gas mitigation policies may be of importance to promote climate policies.This paper argues that the issues of local and regional air pollution and their short to medium-term effects on human health and environment as well as greenhouse gas mitigation policies are environmental policy areas which would benefit from an integrated approach.The paper shows that contemporary Chinese policies aiming at improving energy efficiency and local air quality may lead to large reductions of CO_2.Conversely,an active Chinese climate policy would likely entail reductions in emissions of air pollutants and reduced damage to human health and environment as a co-benefit.The magnitude of these short to medium-term co-benefits is,however,not clear.In the paper we present and compare estimates of co-benefits of CO_2-reducing projects and policies from studies that we have carried out in China.The studies comprise a bottom-up study in the capital of Shanxi province(Taiyuan),a semi-bottom-up study in Shanxi province as a whole,and a top-down study using a computable general equilibrium model(CGE)for China.In comparing the various options for reducing CO_2,we find that the estimated co-benefits per ton carbon reduced show greater variation between options the more detailed the study design is in terms of taking into account local features of emissions and exposure.