近日，澳大利亚西悉尼大学Hannah Carle团队报道了澳大利亚热带森林的地上生物量现在是净碳源。相关论文于2025年10月15日发表在《自然》杂志上。

热带森林作为全球重要的碳汇，地球系统模型预测其短期碳汇能力将持续增强，因为大气二氧化碳浓度升高被认为会促进树木生长。然而，当前森林清查数据分析表明，原始热带森林的碳汇能力可能正在衰退，预示着未来可能从碳汇转变为碳源。

研究组基于澳大利亚湿润热带森林的长期清查数据（1971至2019年），运用因果推断框架评估了木质部地上立木生物量的碳平衡动态、其人口学过程及气候驱动因素（包括气旋影响）。研究发现这些森林的地上木质生物量已实现从碳汇（0.62±0.04兆克碳/公顷/年：1971-2000年）向碳源（-0.93±0.11兆克碳/公顷/年：2010-2019年）的转变，碳汇能力以每年0.041±0.032兆克碳/公顷的速度持续衰退。

这种转变的主要驱动因素是日益极端的高温及其他气候异常，它们导致树木死亡率上升及相应生物量损失，而并未发现二氧化碳对木本植物生长的施肥效应。影响碳汇能力的森林动态还受到气旋干扰，其影响强度与长期气候驱动因素相当。该研究结果表明全球湿润热带森林的地上木质生物量可能对气候变化产生类似响应，最终导致从碳汇向碳源的长期转变。

附：英文原文

Title: Aboveground biomass in Australian tropical forests now a net carbon source

Author: Carle, Hannah, Bauman, David, Evans, Michael N., Coughlin, Ingrid, Binks, Oliver, Ford, Andrew, Bradford, Matthew, Nicotra, Adrienne, Murphy, Helen, Meir, Patrick

Issue&Volume: 2025-10-15

Abstract: Tropical forests act as important global carbon sinks1, and Earth System Models predict increasing near-term carbon sink capacity for these forests, with elevated atmospheric carbon dioxide concentration thought to stimulate tree growth2,3. However, current forest inventory data analyses suggest that the carbon sink capacity of intact tropical forests may be in decline, portending a possible future switch from carbon sinks to carbon sources3,4,5,6,7. Here we use long-term forest inventory data (1971–2019) from Australian moist tropical forests and a causal inference framework8,9,10 to assess the carbon balance of woody aboveground standing biomass over time, the demographic processes accounting for it, and its climatic drivers, including cyclones. We find that a transition from sink (0.62±0.04MgCha1yr1: 1971–2000) to source (0.93±0.11MgCha1yr1: 2010–2019) has occurred for the aboveground woody biomass of these forests, with sink capacity declining at a rate of 0.041±0.032MgCha1yr1. The transition was driven by increasingly extreme temperature and other climate anomalies, which have increased tree mortality and associated biomass losses4, with no evidence of the carbon fertilization (stimulation) of woody tree growth. Forest dynamics underlying carbon sink capacity were also punctuated by cyclones, with impacts of a similar magnitude to long-term climate-induced changes. Our findings suggest the potential for a similar response to climate change by woody aboveground biomass in moist tropical forests globally, which could culminate in a long-term switch from carbon sinks to carbon sources.

DOI: 10.1038/s41586-025-09497-8

Source: https://www.nature.com/articles/s41586-025-09497-8