中国碳收支对全球辐射强迫的影响

Contribution of China's carbon budget to global radiative forcing

中国作为全球最主要的CO_(2)排放国之一和主要贸易国,人为和自然因素均对中国碳收支和全球辐射强迫具有重要作用。但现有研究多单独关注人为或自然因素的作用,尤其缺乏考虑贸易转移的碳排放及其对全球增温影响的研究。本文使用CarbonTracker CT2019B同化数据集和中国贸易排放量数据开展研究。结果表明,全球CO_(2)通量的变化趋势具有明显的空间异质性,这主要是受人为CO_(2)通量的影响。2000—2018年全球及中国化石燃料的碳排放呈现明显的增加趋势,但增加的幅度趋于变缓。2018年中国进出口贸易产生的辐射强迫为-0.0038 W m^(-2),自然碳收支产生的辐射强迫为-0.0027 W m^(-2),分别抵消了当年化石燃料产生辐射强迫的1.54%和1.13%。中国在2000—2018年间化石燃料排放CO_(2)对全球辐射强迫的贡献为11.32%,考虑到中国进出口贸易后,中国人为CO_(2)对全球辐射强迫的贡献为9.50%;进一步考虑到中国陆地生态系统,中国净CO_(2)对全球辐射强迫的贡献下降至7.63%。本文表明了中国陆地生态系统及进出口贸易均在缓解中国对全球增温的作用,也证实了在气候变化研究中把人为和自然源碳收支综合考虑才能系统认知区域或国别碳收支对全球增温的影响。

As the world's largest carbon dioxide(CO_(2))emitter and a major trading country,both anthropogenic and natural factors play an important role in China's carbon budget.However,previous studies mostly focused on evaluating anthropogenic emissions or the natural carbon cycle separately,and few included trade-related(import and export)CO_(2) emissions and its contribution to global warming.Using the CarbonTracker CT2019 assimilation dataset and China trade emissions from the Global Carbon Project,we found that the change trend of global CO_(2) flux had obvious spatial heterogeneity,which was mainly affected by anthropogenic CO_(2) flux.From 2000 to 2018,carbon emissions from fossil fuels in the world and in China showed an obvious increasing trend,but the magnitude of the increase tended to slow down.In 2018,the radiative forcing(RF)caused by China's import and export trade was 0.0038 W m^(-2),and the RF caused by natural carbon budget was-0.0027 W m^(-2),offsetting 1.54%and 1.13%of the RF caused by fossil fuels that year,respectively.From 2000 to 2018,the contribution of China's carbon emission from fossil fuels to global RF was 11.32%.Considering China's import and export trade,the contribution of anthropogenic CO_(2) emission to global RF decreased to 9.50%.Furthermore,taking into account the offset of carbon sink from China's terrestrial ecosystems,the net contribution of China to global RF decreased to 7.63%.This study demonstrates that China's terrestrial ecosystem and import and export trade are all mitigating China's impact on global anthropogenic warming,and also confirms that during the research process on climate change,comprehensively considering the carbon budget from anthropogenic and natural carbon budgets is necessary to a systematic understanding of the impacts of regional or national carbon budgets on global warming.