سود و زیان چین، از سه معاهده مختلف اقلیمی

There are currently several ideas on the table for a climate treaty post-Kyoto. We consider the impact on China of three ideas: a cap on the CO2 intensity, a cap on the CO2 level, and a cap on the CO2 intensity in key sectors. We find that a cap on the CO2 intensity gives large environmental co-benefits to China on aggregate, but there are significant negative effects for rural households. Assuming these are addressed the country could reduce its CO2 intensity by a third before costs outweigh environmental co-benefits. By contrast a cap confined to the manufacturing and power sector does not bring substantial co-benefits to China.

An essential issue in future climate treaties is how to bring developing countries on board. 38 countries have ratified the Kyoto Protocol and committed to greenhouse gas emission reductions. But these countries cover less than a third of global CO2-emissions (IEA, 2007) and the share is falling over time. Hence a future treaty must emphasize emission reductions in the rest of the world including developing countries. Developing countries find it difficult to commit to an emission reduction since it might interfere with the much-needed development of their economies. Besides, greenhouse gas emissions in developing countries are low on a per capita basis. China, for instance, is probably the largest source of CO2-emissions in the world (MNP, 2007), but CO2-emissions per capita are only no. 73 (WRI, 2008). The moral case for prioritizing emission cuts in country no. 73 is weak. The right of developing countries to develop on the one hand, and on the other hand the need for a future climate treaty to include as many developing countries as possible, make it important to know the impact of alternative treaty designs on developing countries. Here we discuss the costs and benefits to China of alternative treaty designs. Because of its size and position as the largest source of CO2-emissions in the world, China is an important representative of developing countries. By illuminating the costs and benefits to China of different treaty designs we are not claiming that the country is on the verge of joining any of them. Although China is taking tentative steps to formulate an active climate policy, e.g., NDRC (2007), the policy discussion in China has a focus on sulfur reductions and energy efficiency rather than explicit CO2 commitments. What we are claiming is that knowing the costs and benefits of different treaty designs is relevant background for policy discussions both in China and internationally.

We have examined the impact on China of different designs of a climate commitment: a comprehensive commitment formulated in the macro CO2 intensity; a comprehensive commitment formulated in the macro CO2 level; and a sectoral commitment in manufacturing and power production. We have examined two policy strategies for implementing a commitment: a tax or transferrable permit on CO2, and a tax or transferrable permit on SO2. Finally we have analyzed sensitivities with respect to environmental valuation, technological substitution and labour migration. The almost unanimous message from the analysis is that China could, and for the sake of its own welfare actually should commit to a significant CO2-reduction. The numbers indicate that the country can reduce CO2-emissions by a third before costs outweigh environmental co-benefits. It is uncertain how much CO2 is emitted from China, but we estimate that about two billion tons of CO2 can be eliminated before costs outweigh benefits. Two billion tons is more than the current emissions of Russia, the third largest emission nation in the world. In fact it equals between 5 and 10% of current global CO2-emissions. Chinese no-regret CO2-emission cuts matter a lot even on a global scale. This is the good news for China—and for the world. The bad news is that CO2-cuts seem to harm poor rural households more than other groups. In fact we find that a CO2-reduction of two billion tons may reduce the standard of living of poor rural households in Shanxi Province by between 5 and 10%. It is not unlikely that a similar effect is present in other provinces relying on mining and heavy industry, including several of the western provinces. The negative effect on poor rural households making a living on 1–2 dollars a day emerges from this work as a major policy challenge for China if and when it commits to CO2-reductions.