Climate Control on Erosion: Evolution of Sediment Flux From Mountainous Catchments During a Global Warming Event, PETM, Southern Pyrenees, Spain

Extreme hydroclimates impact sediment fluxes from mountainous catchments to the oceans. Given modern global warming, a challenge is to assess the sensitivity of erosion in mountainous catchments to extreme climate perturbations. Here, we reconstruct paleo‐sedimentary fluxes across an abrupt global warming, the Paleocene‐Eocene Thermal Maximum (PETM, ∼56 Ma), using sedimentary archives and numerical modeling. In the Tremp Basin (Southern Pyrenees, Spain), our results demonstrate that depositional volumetric rates of siliciclastic sediments increased two‐fold during the PETM. According to the BQART and stream power law models, changes in mean annual temperature and precipitation explain only 9%–27% of the flux increase. This comparison between field data and model predictions suggests that even with high uncertainty on paleoclimate data, extreme rainfall events and landslides may have been crucial sediment generation processes during the PETM. This is consistent with predictions of enhanced climate variability in a warmer world, leading to significant sediment flushing.