Abstract：
The uptake of carbon dioxide (CO2) by terrestrial ecosystems is critical for moderating climate change1. To provide a ground-based long-term assessment of the contribution of forests to terrestrial CO2 uptake, we synthesized in situ forest data from boreal, temperate and tropical biomes spanning three decades. We found that the carbon sink in global forests was steady, at 3.6 ± 0.4 Pg C yr-1 in the 1990s and 2000s, and 3.5 ± 0.4 Pg C yr-1 in the 2010s. Despite this global stability, our analysis revealed some major biome-level changes. Carbon sinks have increased in temperate (+30 ± 5%) and tropical regrowth (+29 ± 8%) forests owing to increases in forest area, but they decreased in boreal (-36 ± 6%) and tropical intact (-31 ± 7%) forests, as a result of intensified disturbances and losses in intact forest area, respectively. Mass-balance studies indicate that the global land carbon sink has increased2, implying an increase in the non-forest-land carbon sink. The global forest sink is equivalent to almost half of fossil-fuel emissions (7.8 ± 0.4 Pg C yr-1 in 1990-2019). However, two-thirds of the benefit from the sink has been negated by tropical deforestation (2.2 ± 0.5 Pg C yr-1 in 1990-2019). Although the global forest sink has endured undiminished for three decades, despite regional variations, it could be weakened by ageing forests, continuing deforestation and further intensification of disturbance regimes1. To protect the carbon sink, land management policies are needed to limit deforestation, promote forest restoration and improve timber-harvesting practices1,3.
摘要：
陆地生态系统吸收二氧化碳（CO2）对于减缓气候变化至关重要1。对森林对陆地二氧化碳吸收的贡献进行基于地面的长期评估，我们合成了北方森林的原位数据，温带和热带生物群落跨越三十年。我们发现全球森林的碳汇是稳定的，在1990年代和2000年代，Cyr-1为3.6±0.4Pg，和3.5±0.4PgCyr-1在2010年代。尽管全球稳定，我们的分析揭示了一些主要的生物群落水平变化.由于森林面积的增加，温带（30±5％）和热带再生长（29±8％）森林的碳汇增加了，但是它们在北方森林（-36±6％）和热带完整森林（-31±7％）中减少，由于完整森林面积的干扰和损失加剧，分别。质量平衡研究表明，全球陆地碳汇增加了2，这意味着非林地碳汇增加。全球森林汇相当于化石燃料排放量的近一半（1990-2019年为7.8±0.4PgCyr-1）。然而,三分之二的收益已被热带森林砍伐所抵消（1990-2019年为2.2±0.5PgCyr-1）。尽管全球森林汇在三十年来一直没有减少，尽管区域差异，它可能会被老化的森林削弱，持续的森林砍伐和进一步加剧的干扰机制1。为了保护碳汇，需要土地管理政策来限制森林砍伐，促进森林恢复，改善木材采伐做法1，3。
