Estimating regional flood discharge during Palaeocene-Eocene global warming.
Chen Chen, Laure Guerit, Brady Z Foreman, Hima J Hassenruck-Gudipati, Thierry Adatte, Louis Honegger, Marc Perret, Appy Sluijs, Sébastien Castelltort
Author Information
Chen Chen: Department of Earth Sciences, University of Geneva, Rue des Maraîchers 13, 1205, Geneva, Switzerland.
Laure Guerit: Department of Earth Sciences, University of Geneva, Rue des Maraîchers 13, 1205, Geneva, Switzerland.
Brady Z Foreman: Department of Geology, Western Washington University, Bellingham, Washington, 98225, USA. ORCID
Hima J Hassenruck-Gudipati: Jackson School of Geosciences, The University of Texas at Austin, 2305 Speedway Stop, C1160, Austin, Texas, USA.
Thierry Adatte: ISTE, Geopolis, University of Lausanne, 1015, Lausanne, Switzerland.
Louis Honegger: Department of Earth Sciences, University of Geneva, Rue des Maraîchers 13, 1205, Geneva, Switzerland.
Marc Perret: Department of Earth Sciences, University of Geneva, Rue des Maraîchers 13, 1205, Geneva, Switzerland.
Appy Sluijs: Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Heidelberglaan 2, 3584CS, Utrecht, Netherlands.
Sébastien Castelltort: Department of Earth Sciences, University of Geneva, Rue des Maraîchers 13, 1205, Geneva, Switzerland. sebastien.castelltort@unige.ch. ORCID
Among the most urgent challenges in future climate change scenarios is accurately predicting the magnitude to which precipitation extremes will intensify. Analogous changes have been reported for an episode of millennial-scale 5 °C warming, termed the Palaeocene-Eocene Thermal Maximum (PETM; 56 Ma), providing independent constraints on hydrological response to global warming. However, quantifying hydrologic extremes during geologic global warming analogs has proven difficult. Here we show that water discharge increased by at least 1.35 and potentially up to 14 times during the early phase of the PETM in northern Spain. We base these estimates on analyses of channel dimensions, sediment grain size, and palaeochannel gradients across the early PETM, which is regionally marked by an abrupt transition from overbank palaeosol deposits to conglomeratic fluvial sequences. We infer that extreme floods and channel mobility quickly denuded surrounding soil-mantled landscapes, plausibly enhanced by regional vegetation decline, and exported enormous quantities of terrigenous material towards the ocean. These results support hypotheses that extreme rainfall events and associated risks of flooding increase with global warming at similar, but potentially at much higher, magnitudes than currently predicted.
References
Science. 2016 May 6;352(6286):694-7
[PMID: 27151865]
