Randerson James T, Li Yue, Fu Weiwei, Primeau Francois, Kim Jinhyuk E, Mu Mingquan, Hoffman Forrest M, Trugman Anna T, Yang Linqing, Wu Chao, Wang Jonathan A, Anderegg William R L, Baccini Alessandro, Friedl Mark A, Saatchi Sassan S, Denning A Scott, Goulden Michael L
Department of Earth System Science, University of California, Irvine, CA 92697, USA.
Department of Civil and Environmental Engineering, University of California, Irvine, CA 92697, USA.
Sci Adv. 2025 Sep 12;11(37):eadr5489. doi: 10.1126/sciadv.adr5489. Epub 2025 Sep 10.
Over the past three decades, assessments of the contemporary global carbon budget consistently report a strong net land carbon sink. Here, we review evidence supporting this paradigm and quantify the differences in global and Northern Hemisphere estimates of the net land sink derived from atmospheric inversion and satellite-derived vegetation biomass time series. Our analysis, combined with additional synthesis, supports a hypothesis that the net land sink is substantially weaker than commonly reported. At a global scale, our estimate of the net land carbon sink is 0.8 ± 0.7 petagrams of carbon per year from 2000 through 2019, nearly a factor of two lower than the Global Carbon Project estimate. With concurrent adjustments to ocean (+8%) and fossil fuel (-6%) fluxes, we develop a budget that partially reconciles key constraints provided by vegetation carbon, the north-south CO gradient, and O trends. We further outline potential modifications to models to improve agreement with a weaker land sink and describe several approaches for testing the hypothesis.
在过去三十年中，对当代全球碳预算的评估始终报告陆地存在强劲的净碳汇。在此，我们回顾支持这一范式的证据，并量化源自大气反演和卫星衍生植被生物量时间序列的全球和北半球净陆地碳汇估计值之间的差异。我们的分析与其他综合分析相结合，支持了一个假设，即净陆地碳汇比通常报告的要弱得多。在全球范围内，我们对2000年至2019年净陆地碳汇的估计为每年0.8±0.7皮克碳，几乎比全球碳项目的估计低了一半。通过同时调整海洋通量（+8%）和化石燃料通量（-6%），我们制定了一个预算，部分调和了植被碳、南北CO梯度和O趋势提供的关键约束。我们进一步概述了对模型的潜在修改，以改善与较弱陆地碳汇的一致性，并描述了几种检验该假设的方法。
