基于各国NDC/INDC目标的全球减排不确定性研究

doi:10.12006/j.issn.1673-1719.2020.104

摘要/Abstract

摘要：

基于各国提交的165份国家自主贡献文件,以其中提出的减排目标为基准,尽可能充分地考虑了减排目标的范围不确定性、不同经济情景带来的碳强度减排目标不确定性、减排气体种类边界差异、碳排放达峰约束等因素,并通过蒙特卡洛模拟的方法对全球、各区域和主要经济体的温室气体排放总量、不确定度及其来源进行了定量分析。结果表明,到2030年全球温室气体排放总量将达到62.69 Gt CO₂当量,其90%信度的置信区间为53.17~74.26 Gt CO₂当量;由于未来经济总量预期不确定对排放量的影响最显著,因此,不同地区之间不确定性来源差异较大。同时,基于到2050年排放总量比2010年下降40%~70%的2℃目标排放情景,2030—2050年全球温室气体排放年均需要下降5.0% %。为了尽可能减小全球温室气体排放预期目标的不确定性和继续实现2℃目标,各国在进行自主贡献文件更新时进一步提出统计边界更为明确和统一且更有雄心的减排目标将是第一次全球盘点继续解决的重点问题。

关键词: 国家自主贡献（NDCs）, 巴黎协定, 减排目标, 不确定性

Abstract:

Based on the 165 Nationally Determined Contributions/Intended Nationally Determined Contributions (NDC/INDCs) submitted by countries, the emission reduction targets proposed in NDC/INDCs were taken as the benchmark in this paper. Some factors were considered including the uncertainty of the scope of the emission reduction target, the uncertainty of the carbon intensity reduction target derived from economic scenarios, boundary differences of emission reduction gas type and carbon emission peak constraints, and Monte Carlo simulation were used to quantitatively analyze GHG emissions, uncertainties and their sources of global, regional, and major economies. The results show that by 2030, the total global GHG emissions will reach 62.69 Gt CO₂e, with a 90% confidence interval of 53.17-74.26 Gt CO₂e; since the uncertainty of expected future economy has the most significant impact on emissions, the sources of uncertainty vary greatly among regions. Meanwhile, based on the 2℃ target emission scenario where total emissions by 2050 are 40%-70% lower than in 2010, global GHG emissions need to be reduced by 5.0% % annually from 2030 to 2050. In order to minimize the uncertainty of the global GHG emissions target and continue to work towards the completion of the 2℃ target, countries have to further propose clearer and unified statistical boundaries and more ambitious emission reduction targets when updating their NDCs during the first global stock take.

Key words: NDC/INDCs, Paris Agreement, Emission reduction target, Uncertainty

陈楠, 林炫辰. 基于各国NDC/INDC目标的全球减排不确定性研究[J]. 气候变化研究进展, 2021, 17(2): 223-235.

CHEN Nan, LIN Xuan-Chen. Estimation of uncertainty based on emission reduction targets in NDC/INDCs[J]. Climate Change Research, 2021, 17(2): 223-235.

图/表 9

图1 中国碳排放达峰目标分析流程图

Fig. 1 Flow chart of China’s CO2 emission peaking target analysis

图2 NDC/INDCs减排目标不确定性分析蒙特卡洛模拟路径图注：Ei（i=1,2,…,7）为模拟各个阶段所产生的温室气体排放量阶段值（t CO2e);Ef为模拟的最终温室气体排放量（t CO2e),包括各个国家以及相应的区域和全球合计;I为碳排放强度（t CO2e/万元)。σi（i=1,2,…,6）为各个影响因素作为随机变量考虑所引入的不确定度。具体各不确定度对应的影响因素、随机变量以及相应的分布函数如表1所示。

Fig. 2 Monte Carlo simulation analysis path of uncertainty of NDC/INDCs emission reduction target

表1 不确定性因素作为随机变量

Table 1 Uncertainty factors as random variables

表2 不同研究给出的全球及主要国家和地区的2030年温室气体排放量

Table 2 2030 GHG emissions of the globe and a few major regions estimated by various studies Gt CO2e

表3 各种因素对全球2030年温室气体排放量的不确定度贡献

Table 3 Uncertainty attributable to various identified drivers in 2030 global emissions

图3 CEPII模型数据库下不同SSP情景2030年全球温室气体排放量分布注：其中纵坐标为蒙特卡洛模拟在区间范围的结果计数。

Fig. 3 Distribution of global GHG emissions under different SSP scenarios using CEPII model database

图4 各地区2030年排放量不确定度来源（CEPII模型）

Fig. 4 Sources of uncertainty in emissions by region in 2030 (CEPII model)

图5 全球及主要国家和经济体2010、2030年人均排放量注：图中2030年人均排放量以四分位数的盒图表示。

Fig. 5 Global and major countries’ and economies’ emissions per capita in 2010 and 2030

图6 2℃情景下2010,2030及2050年全球温室气体排放量及不确定度

Fig. 6 Global emissions and uncertainty ranges in 2010, 2030 and 2050 under the 2℃ target emission scenario

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