1. Sensitivity of glacially-fed rivers to rapid climate change: Ladakh, NW Himalaya Daniel Hobley Supervisors: Hugh Sinclair, Patience Cowie, Tibor Dunai Grant Institute

2. ? “Late Cenozoic uplift of mountain ranges and global climate change: chicken or egg?” (Molnar & England, 1990) Disequilibrium alters process rates Timescales? Erosive mechanisms? Relative importance?

3. Glacial rivers vs normal rivers Enhanced erosion Enhanced discharge Reduced variability Temperature controlled Altered sediments …but with Jokulhlaups Signals transmitted …we need to quantify these effects.

4. Study area: Ladakh, NW Himalaya Restricted glacial area, variable down batholith Simple chronology Dry (Arctic desert) Constant forcings Limited human alteration Many comparable catchments 100km

5. Approach 1. GIS study Unglaciated catchment Typical fluvial profile Glaciated catchment Fluvial section Major knickpoint Increased concavity (elevated erosion rates) Slope plot Max modern glacial extent Approx extent of significant glacial alteration DEMs used to obtain channel form, drainage area, slope data

6. 2. Fieldwork Groundtruthing Measuring critical field parameters… …and how they vary downstream Cosmogenic samples Compare glaciated and unglaciated catchments Sediment supplied Channel morphometry Sediment caliber Channel width Modern glacial behaviour Nature of knickpoint & gorging

7. (Crave & Davy 2001) 3. Modelling Can we mechanistically understand the response to the imposed disequilibrium? Shape vs hydrology Analytical models? Or numerical? (e.g., EROS) Non-“steady state” analysis required…

8. Outstanding questions Glaciers seem to increase downstream erosion, but… Fluvial (shape) vs glacial (hydrological) response? Distribution of erosion in time? Lifetimes of various aspects of disequilibrium? Can we scale up? (e.g., to Indus) Understanding of transient responses of systems?