Warming-induced global soil carbon loss attenuated by downward carbon movement

Zhongkui Luo, Yiqi Luo, Guocheng Wang, Jianyang Xia, Changhui Peng

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

The fate of soil organic carbon (SOC) under warming is poorly understood, particularly across large extents and in the whole-soil profile. Using a data-model integration approach applied across the globe, we find that downward movement of SOC along the soil profile reduces SOC loss under warming. We predict that global SOC stocks (down to 2 m) will decline by 4% (~80 Pg) on average when SOC reaches the steady state under 2°C warming, assuming no changes in net primary productivity (NPP). To compensate such decline (i.e. maintain current SOC stocks), a 3% increase of NPP is required. Without the downward SOC movement, global SOC declines by 15%, while a 20% increase in NPP is needed to compensate that loss. This vital role of downward SOC movement in controlling whole-soil profile SOC dynamics in response to warming is due to the protection afforded to downward-moving SOC by depth, indicated by much longer residence times of SOC in deeper layers. Additionally, we find that this protection could not be counteracted by promoted decomposition due to the priming of downward-moving new SOC from upper layers on native old SOC in deeper layers. This study provides the first estimation of whole-soil SOC changes under warming and additional NPP required to compensate such changes across the globe, and reveals the vital role of downward movement of SOC in reducing SOC loss under global warming.

Original languageEnglish (US)
Pages (from-to)7242-7254
Number of pages13
JournalGlobal change biology
Volume26
Issue number12
DOIs
StatePublished - Dec 2020

Keywords

  • carbon model
  • carbon sequestration
  • carbon stock
  • deep soil carbon
  • leaching
  • priming effect
  • temperature sensitivity
  • warming

ASJC Scopus subject areas

  • Global and Planetary Change
  • Environmental Chemistry
  • Ecology
  • Environmental Science(all)

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