Nature Communications (Oct 2024)

A supply-limited torrent that does not feel the heat of climate change

  • Jiazhi Qie,
  • Adrien Favillier,
  • Frédéric Liébault,
  • Juan Antonio Ballesteros Cánovas,
  • Jérôme Lopez-Saez,
  • Sébastien Guillet,
  • Loïc Francon,
  • Yihua Zhong,
  • Markus Stoffel,
  • Christophe Corona

DOI
https://doi.org/10.1038/s41467-024-53316-z
Journal volume & issue
Vol. 15, no. 1
pp. 1 – 10

Abstract

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Abstract Debris-flow activity in the Alps is anticipated to undergo pronounced changes in response to a warming climate. Yet, a fundamental challenge in comprehensively assessing changes in process activity is the systematic lack of long-term observational debris-flow records. Here, we reconstruct the longest, continuous time series (1626-2020) of debris flows at Multetta, a supply-limited torrential system in the Eastern Swiss Alps. Relying on growth-ring records of trees that were damaged by debris flows, we do not detect significant changes in the frequency or magnitude over time. This seeming absence of a direct climatic influence on debris-flow initiation aligns with the regular distribution of repose time patterns, indicating a dependence of local process activity on sediment discharge and recharge. This stark difference in process behavior between our supply-limited site and transport-limited catchments has implications for assessing torrential hazard and risk mitigation in a context of global warming.