Featured Science Paper
Acceleration of snow melt in an Antarctic Peninsula ice core during the twentieth century
This paper reports the use of a ‘linescan’ optical record from the James Ross Island ice core (continuous scanning through slabs of ice cut from along the length of the core) to record melt layers in the ice. Surprisingly perhaps, this paper is the first long, detailed, melt record from Antarctica. It demonstrates that the intensity of melting in the near-surface snow cover at this site is higher in the last few decades than at any point in the last 1000 years. Melting correlates well with temperature at the site (from the stable water isotope record) — the coldest conditions around 1450 were about 1.6°C lower than present, and shows the least melting. The warming from then to the present day has increased the melt intensity by around ten-fold to the point where about 5% of the snowfall on JRI now melts.
While the melting at this site is not, on its own, indicative of increased regional melting, it does graphically demonstrate that once the temperature/energy balance conditions for melting are reached, any further warming leads to rapidly melting surfaces. This is relevant to surface melting, percolation and destabilisation of lower altitude glaciers and ice shelves.
Nerilie J. Abram, Robert Mulvaney et al.
Nature Geoscience, 6, (5). 404-411