PROXYMELT - Ice Core Climate Records in a Warming World

Ongoing global warming is driving surface melt into previously unaffected regions of the Greenland Ice Sheet, threatening this invaluable paleoclimate archive. On high alpine glaciers, meltwater percolating through snow layers has already degraded climate proxy records archived in the snow’s water isotopic composition. In Greenland, where ice cores for climate research have been preferentially drilled and where melt has historically been rare, the effects of melt-percolation and freezing processes on the stable water isotope climate proxy record have not been quantified. However, as the frequency and spatial extent of melt increase, future climate studies will depend on climate proxy records from melt-affected regions in Greenland. Consequently, a comprehensive understanding of how melt and refrozen meltwater influence the water isotope signal in snow is essential. PROXYMELT will use a comprehensive dataset of snow microstructure and stable water isotope information derived from a network of Greenland snow, firn, and ice cores, along with cold-laboratory melt experiments, to enhance the understanding of how snowmelt impacts climate records. Further, it will assess whether the melt fingerprint left in the stable water isotope record can, in turn, be used to reconstruct past melt events. It is the ambition of PROXYMELT not only to facilitate continued climate research on melt-affected water isotope ice core records but to extract supplementary and otherwise inaccessible climate information from water isotope records by establishing them as a novel melt proxy. In summary, PROXYMELT will extend the use of stable water isotopes in melt-affected ice cores while simultaneously broadening the research scope and skills of a promising and ambitious scientist, from surface snow to deeper ice. The project will position her at the nexus between the snow and ice core communities at the onset of times when melting is expected to impact both fields in polar regions increasingly.