Global Carbon Budget 2020
Global Carbon Budget 2020
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DOI：
10.5194/essd-12-3269-2020
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发表时间：
2020-12-11
影响因子：
11.4
通讯作者：
Zaehle, Sonke
中科院分区：
文献类型：
--
作者：
Friedlingstein, Pierre;O'Sullivan, Michael;Zaehle, Sonke
准确评估人类活动产生的二氧化碳排放及其在气候变化中在大气、海洋和陆地生物圈中的再分配--“全球碳预算”--对于更好地理解全球碳循环、支持气候政策的制定和预测未来气候变化非常重要。在这里，我们描述和综合数据集和方法来量化全球碳预算的五个主要组成部分及其不确定性。化石CO2排放量是根据能源统计和水泥生产数据计算的，而土地利用变化（主要是毁林）排放量是根据土地利用和土地利用变化数据和簿记模型计算的。大气CO2浓度直接测量，其增长率（G（ATM））计算从浓度的年变化。利用观测约束的全球过程模式估算了海洋CO2汇（SOCEAN）和陆地CO2汇（S-LAND）。由此产生的碳收支不平衡（B-IM），即估计的总排放量与估计的大气、海洋和陆地生物圈变化之间的差异，是对当代碳循环不完善数据和理解的一种衡量。所有不确定性报告为+/- 1 sigma。在过去十年（2010-2019年），E-FOS为9.6 +/- 0.5 GtC yr（-1），不包括水泥碳酸化汇（9.4 +/- 0.5 GtC yr（-1），包括水泥碳酸化汇），ELUC为1.6 +/- 0.7 GtC yr（-1）。在同一个十年中，全球大气环流模式为5.1 +/- 0.02 GtC yr（-1）（2.4 +/- 0.01 ppm yr（-1）），海洋生态系统评估为2.5 +/- 0.6 GtC yr（-1），土地利用率为3.4 +/- 0.9 GtC yr（-1），预算不平衡BIM为0.1 GtC yr（-1），表明在过去十年中估算的源和汇之间接近平衡。仅在2019年，EFOS的增长仅约为0.1%，化石排放量增加至9.9 +/- 0.5 GtC yr（-1），不包括水泥碳酸化汇（9.7 +/- 0.5 GtC yr（-1），包括水泥碳酸化汇），ELUC为1.8 +/- 0.7 GtC yr（-1），人为CO2排放总量为11.5 +/- 0.9 GtC yr 1（42.2 +/- 3.3 GtCO（2））。同样在2019年，GATM为5.4 +/- 0.2 GtC yr 1（2.5 +/- 0.1 ppm yr 1），SOCEAN为2.6 +/- 0.6 GtC yr 1，SLAND为3.1 +/- 1.2 GtC yr（-1），BIM为0.3 GtC。2019年全球大气二氧化碳浓度平均达到409.85 +/- 0.1 ppm。2020年的初步数据，考虑到COVID-19引起的排放变化，表明EFOS相对于2019年减少约7%（中位数估计），这是基于四项研究的6%，7%，7%（3%至11%）和13%的单独估计。总的来说，全球碳收支各组成部分的平均值和趋势在1959-2019年期间得到了一致的估计，但在CO2通量的半年度变化的代表性方面存在高达1 GtC yr 1的差异。对不同方法和观测结果的估计值进行比较表明：（1）在过去十年中土地利用变化排放的平均值和趋势方面没有达成共识，（2）不同方法对北方热带外陆地CO2通量的一致性持续较低;（3）不同方法对热带外海洋汇的一致性明显不同，特别是在南大洋。这一动态数据更新记录了这一新的全球碳预算中使用的方法和数据集的变化，以及与该数据集以前的出版物相比，在理解全球碳循环方面取得的进展（Friedlingstein等人，2019; Le Quere等人，2018 b，a，2016，2015 b，a，2014，2013）。本工作中提供的数据可在https://doi.org/10.18160/gcp-2020获得（Friedlingstein等人，2020年）。
Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate - the "global carbon budget" - is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesize data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2 emissions ( EFOS) are based on energy statistics and cement production data, while emissions from land-use change ( ELUC), mainly deforestation, are based on land use and land-use change data and bookkeeping models. Atmospheric CO2 concentration is measured directly and its growth rate (G(ATM)) is computed from the annual changes in concentration. The ocean CO2 sink ( SOCEAN) and terrestrial CO2 sink ( S-LAND) are estimated with global process models constrained by observations. The resulting carbon budget imbalance ( B-IM), the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a measure of imperfect data and understanding of the contemporary carbon cycle. All uncertainties are reported as +/- 1 sigma. For the last decade available (2010-2019), E-FOS was 9.6 +/- 0.5 GtC yr(-1) excluding the cement carbonation sink (9.4 +/- 0.5 GtC yr(-1) when the cement carbonation sink is included), and ELUC was 1.6 +/- 0.7 GtC yr(-1). For the same decade, GATM was 5.1 +/- 0.02 GtC yr(-1) (2.4 +/- 0.01 ppm yr(-1)), SOCEAN 2.5 +/- 0.6 GtC yr(-1) and SLAND 3.4 +/- 0.9 GtC yr(-1), with a budget imbalance BIM of 0.1 GtC yr(-1) indicating a near balance between estimated sources and sinks over the last decade. For the year 2019 alone, the growth in EFOS was only about 0.1% with fossil emissions increasing to 9.9 +/- 0.5 GtC yr(-1) excluding the cement carbonation sink (9.7 +/- 0.5 GtC yr(-1) when cement carbonation sink is included), and ELUC was 1.8 +/- 0.7 GtC yr(-1), for total anthropogenic CO2 emissions of 11.5 +/- 0.9 GtC yr 1 (42.2 +/- 3.3 GtCO(2)). Also for 2019, GATM was 5.4 +/- 0.2 GtC yr 1 (2.5 +/- 0.1 ppm yr 1), SOCEAN was 2.6 +/- 0.6 GtC yr 1, and SLAND was 3.1 +/- 1.2 GtC yr(-1), with a BIM of 0.3 GtC. The global atmospheric CO2 concentration reached 409.85 +/- 0.1 ppm averaged over 2019. Preliminary data for 2020, accounting for the COVID-19-induced changes in emissions, suggest a decrease in EFOS relative to 2019 of about 7% (median estimate) based on individual estimates from four studies of 6 %, 7 %, 7% ( 3% to 11 %), and 13 %. Overall, the mean and trend in the components of the global carbon budget are consistently estimated over the period 1959-2019, but discrepancies of up to 1 GtC yr 1 persist for the representation of semi-decadal variability in CO2 fluxes.Comparison of estimates from diverse approaches and observations shows (1) no consensus in the mean and trend in land-use change emissions over the last decade, (2) a persistent low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) an apparent discrepancy between the different methods for the ocean sink outside the tropics, particularly in the Southern Ocean. This living data update documents changes in the methods and data sets used in this new global carbon budget and the progress in understanding of the global carbon cycle compared with previous publications of this data set (Friedlingstein et al., 2019; Le Quere et al., 2018b, a, 2016, 2015b, a, 2014, 2013). The data presented in this work are available at https://doi.org/10.18160/gcp-2020 (Friedlingstein et al., 2020).