University of Bucharest, Faculty of Geography, 1 Nicolae Bălcescu Street, 010041, Bucharest, Romania; University of Bucharest, Research Institute of the University of Bucharest (ICUB)/Romanian Young Academy, 90-92 Sos. Panduri, 5th District, 050663, Bucharest, Romania.
National Meteorological Administration (Meteo Romania), Department of Research and Meteo Infrastructure Projects, 97 București-Ploiești Street, 013686, Bucharest, Romania; Alexandru Ioan Cuza University, Faculty of Geography and Geology, Department of Geography, 20A Carol I Street, 700506, Iaşi, Romania.
Environ Res. 2021 Oct;201:111580. doi: 10.1016/j.envres.2021.111580. Epub 2021 Jun 26.
Soil organic carbon (SOC) is a critical indicator for healthy and fertile lands across the world. It is also the planet's largest terrestrial carbon pool, so any changes of this pool may have profound implications for both land productivity and climate stability. However, SOC changes have so far remained largely unexplored, although their understanding is essential for many international environmental policies. Here we investigate for the first time recent global SOC changes, based on some SOC stock interannual data that were processed for the 2001-2015 period on a planetary scale. We analysed the global SOC dynamics using the Mann-Kendall test and Sen's slope estimator, which are widely acknowledged to be reliable geostatistical tools for detecting various environmental trends from global to local scale. We explored SOC changes via three metrics (averages, quantities, areas) of negative and positive trends, but also of the balance between soil carbon trends, a key statistic for monitoring land quality stability and soil-atmosphere carbon fluxes in the global environmental policies. Globally, we estimated a net average decrease of -58.6 t C km yr, a total loss of ~3.1 Pg C, and an area affected by net SOC losses of ~1.9 million km. Using this triple statistic, we found that 79% of countries worldwide have been affected by net declines of SOC after 2001, which suggests that halting land degradation and mitigating climate change through the SOC pathway are still far from being achieved by international policies.
土壤有机碳 (SOC) 是全球健康肥沃土地的关键指标。它也是地球上最大的陆地碳库，因此这个碳库的任何变化都可能对土地生产力和气候稳定性产生深远影响。然而，到目前为止，SOC 的变化在很大程度上仍未得到探索，尽管了解 SOC 的变化对于许多国际环境政策至关重要。在这里，我们首次根据一些 SOC 存量的年际数据，对 2001-2015 年期间进行了行星尺度的处理，调查了最近全球 SOC 的变化情况。我们使用曼恩-肯德尔检验和 Sen 斜率估计器分析了全球 SOC 动态，这两种方法被广泛认为是从全球到局部尺度检测各种环境趋势的可靠地统计学工具。我们通过负趋势和正趋势的平均值、数量和面积这三个指标，以及监测土地质量稳定性和全球环境政策中土壤-大气碳通量的土壤碳趋势之间的平衡来探索 SOC 的变化。全球范围内，我们估计净平均下降了-58.6 t C km yr，总损失约为 3.1 Pg C，受到净 SOC 损失影响的面积约为 190 万 km。使用这三个统计指标，我们发现全球 79%的国家在 2001 年后受到 SOC 净减少的影响，这表明通过 SOC 途径停止土地退化和减缓气候变化的目标在国际政策层面上仍远未实现。
