PhD defence: Jeppe Kjeldahl Malmros – Københavns Universitet

IGN > Ph.d.-forsvar > 2019 > PhD defence: Jeppe Kje...

PhD defence: Jeppe Kjeldahl Malmros

Jeppe Kjeldahl Malmros defends his PhD thesis

Snow and ice changes in the Andes – Assessing trends and drivers from 1950's to present day 

Supervisors
Professor Rasmus Fensholt, IGN
Professor Sebastian H Mernild, NERSC 

Assessment Committee
Professor Jason Box, GEUS
Professor Francesca Pellicciotti, Northumbria University
Associate Professor Birger Hansen (chair), IGN 

After the PhD defence there will be a reception in Rød Stue, Øster Voldgade 10, Area 6, First floor – everybody is welcome

Summary
This dissertation aims to improve our understanding of the cryosphere, its evolution and drivers specific to the Andes Cordillera of South America, especially related to snow cover, glacier area, and glacier mass-balance. The cryosphere of the Andes Cordillera is undergoing changes at a rapid and accelerating pace. Reductions in snow and ice cover impact surface energy and hydrological balances in affected areas. Also affected are populations who rely on the steady flow of river freshwater for irrigation, drinking, and in hydropower production that originate from snow and ice melt. Retreat and melting of glaciers often leads to a redistribution of seasonal runoff regimes leaving a reduced river runoff in late summer. Subsequently, the added meltwater contributes to sea-level rise with global impact. This thesis improves our knowledge about ice and snow conditions in the Andes from 1955 to 2016. It examines the impact from drivers of change, e.g., temperature, precipitation and large-scale atmospheric oscillations and utilizes a wide range of time-series including remote sensing imagery, climate station data, glacier mass-balance observations, as well as measured and modelled climate forcing, and simulated data to explore and improve our current knowledge of climate change impacts in the cryosphere of the Andes Cordillera.

This thesis shows that glaciers in the Andes Cordillera are negatively out of balance with current climate. Especially glaciers in the north and central parts of the Andes show negative mass-balances. In addition, glacier area changes in the central Andes of Chile and Argentina show recession on average 30% since the 1950’s, recession rates that are accelerating. The state and evolution of glaciers in the Andes links with ongoing climate warming and changing precipitation patterns influenced by large-scale climate oscillations. If these climate conditions are to persist over longer periods it will have severe effects on available freshwater resources.

The thesis is available from the PhD administration office 04.1.417