Postdoctoral Fellowship: EAR-PF: Linking the past to the future: Using PETM fluvial records to understand the effects of climate change on rivers

Howes, Bolton John, Princeton NJ

Investigators

Abstract

Dr. Bolton Howes has been awarded an NSF Earth Sciences Postdoctoral Fellowship to carry out research and professional development activities under the mentorship of Dr. Akshay Mehra at the University of Washington and Dr. Brady Foreman at Western Washington University. From providing irrigation and nourishment for agriculture to acting as transport routes that connect inland areas to the coasts, rivers and floodplains are critical to the functioning of humanity and our planet. Rivers and floodplains also are highly sensitive to changes in climate, vegetation cover, and land use. Since rivers can pose risks to cities, agriculture, and infrastructure through flooding and the movement of channels, it is crucial to understand how river systems will respond to ongoing climate change. For clues about the future of rivers, geologists can turn to the sedimentary record. The Paleocene-Eocene Thermal Maximum (PETM) represents a significant period of rapid warming in our planet's past, analogous to the current climatic changes. Scientists know that the environmental changes triggered by the PETM affected sediment patterns and river behavior. For instance, research indicates an increase in channel movement at several locations during the PETM. Increased mobility in modern rivers could lead to infrastructure damage, alterations in water availability, and shifts in navigational routes. This project has two objectives: (1) to determine if the increased channel movement during the PETM was specific to certain basins or a widespread phenomenon, and (2) to use historical data from satellites and surveys to ascertain if anthropogenic climate change has led to increased migration rates of modern rivers. The findings of this project will provide valuable insights into how humanity can better prepare for anticipated changes in river systems over the coming century. This project will also culminate in the development and dissemination of open-source software for 3D modeling. Undergraduate students will be active contributors to the research, learning skills in field geology and quantitative methods for the geosciences. Finally, the project will foster public engagement through lectures at museums within the field area. This project employs a two-pronged approach to explore the impacts of climate change on the behavior of fluvial landscapes. First, the project will utilize traditional stratigraphic techniques in conjunction with drone-derived digital elevation models and photo-orthomosaics to measure the morphology and size of fluvial sandstones before, during and after the PETM in the Piceance, Hanna, and Bighorn Basins. Three-dimensional models, created from drone imagery, will facilitate more accurate measurements of ancient rivers geometry and improve the estimation of uncertainty and lateral variability. These measurements will enable the project to accurately characterize the changing fluvial dynamics induced by the heightened temperatures and increased seasonality during the PETM. Secondly, the project will employ historical records of modern rivers, sourced from satellite imagery, maps, and surveys, to ascertain if anthropogenic climate change and alterations in land use have influenced modern river behavior. This analysis of modern rivers will determine if modern rivers have already adjusted to the changing climate, or if (and how much) infrastructure plans need to accommodate future change in fluvial landscape behavior. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.