Scholarlink

<p>Permafrost carbon vulnerability, particularly concerning temperature thresholds and old carbon mobilization, remains a critical uncertainty in climate projections. Through a five-year, multi-level warming experiment on the Tibetan Plateau, we investigate these dynamics using &gt;40,000 hourly flux measurements combined with vertical CO<sub>2</sub> concentration and δ<sup>13</sup>C-CO<sub>2</sub> profiling. Here we demonstrate under low-to-moderate warming (&lt;2 °C), respiratory carbon loss (<i>R</i><sub>eco</sub>) increments exceed photosynthetic carbon uptake (GPP) gains by 1–16 fold, driving a quantitative shift toward ecosystem carbon source. Extreme warming (2−4 °C) triggers a surge in growing-season deep carbon loss to 59% <i>R</i><sub>eco</sub>, while GPP declines precipitously. The decoupling between <i>R</i><sub>eco</sub> and GPP drives a qualitative transition to strong carbon source, implying the existence of a tipping point within 2−4 °C. Projected to end-of-century warming levels (2.69 °C) across Tibetan permafrost regions, this could release 24−47 g CO<sub>2</sub> m<sup>−2</sup> yr<sup>−1</sup> old carbon. These findings establish quantitative thresholds for permafrost carbon vulnerability and inform carbon-climate feedback projections in global cold regions.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Permafrost tipping point triggered by warming-driven loss of old carbon

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年4月17日

查看全文
  • Yuxi Wei,
  • Juan Li,
  • Xiling Gu,
  • Huangyu Huo,
  • Tao Wang,
  • Shiping Wang,
  • Baosheng An,
  • Tandong Yao,
  • Shilong Piao,
  • Jinzhi Ding

摘要

Permafrost carbon vulnerability, particularly concerning temperature thresholds and old carbon mobilization, remains a critical uncertainty in climate projections. Through a five-year, multi-level warming experiment on the Tibetan Plateau, we investigate these dynamics using >40,000 hourly flux measurements combined with vertical CO2 concentration and δ13C-CO2 profiling. Here we demonstrate under low-to-moderate warming (<2 °C), respiratory carbon loss (Reco) increments exceed photosynthetic carbon uptake (GPP) gains by 1–16 fold, driving a quantitative shift toward ecosystem carbon source. Extreme warming (2−4 °C) triggers a surge in growing-season deep carbon loss to 59% Reco, while GPP declines precipitously. The decoupling between Reco and GPP drives a qualitative transition to strong carbon source, implying the existence of a tipping point within 2−4 °C. Projected to end-of-century warming levels (2.69 °C) across Tibetan permafrost regions, this could release 24−47 g CO2 m−2 yr−1 old carbon. These findings establish quantitative thresholds for permafrost carbon vulnerability and inform carbon-climate feedback projections in global cold regions.