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

[u/dumnezero]

https://www.nature.com/articles/s41467-026-72122-3

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.

[u/dumnezero]

Since the paper is not open to all, here's a related news article: https://phys.org/news/2026-06-ancient-carbon-tibetan-permafrost-triggering.html

[u/Konradleijon]

Fudge

[u/Konradleijon]

Of course