Australia: The Land Where Time Began

A biography of the Australian continent 

Greenland’s Marine Terminating Glaciers – Changes to Understanding the Dynamic Response to Oceanic and Atmospheric Forcing

The contribution of the Greenland ice sheet to sea level rise of 0.6 ± 0.1 mm/yr and the discharge of its water into the North Atlantic have been increased by the recent retreat and increasing speed of outlet glaciers, as well as enhanced melting at the surface around the margin of the ice sheet. According to Straneo et al. a common driver is suggested by the widespread retreat of glaciers that is near-synchronous, and its coincidence with a time when oceanic and atmospheric warming is occurring. The margins of these glaciers are pointed to by the available evidence as the regions from which changes propagated inland. The forcings and mechanisms on which these dynamic changes are based are not well understood and in climate and ice sheet models they are either missing or parameterised crudely. As a result the sea level rises contributions from Greenland by 2100 that have been projected have remained largely uncertain.

In this paper Straneo et al. have summarised the current state of knowledge as well as highlighting key physical aspects of the coupled ice-sheet-ocean-atmosphere system of Greenland. There are 3 research thrusts that have been identified as yielding fundamental insights into ice sheet, ocean, sea ice, and atmosphere interactions, their role in the climate system of the Earth, and probably trajectories of changes into the future:

1.      Focused studies that address critical glacier, ocean, atmosphere, and coupled dynamics;

2.      Sustained observations at key sites;

3.      Inclusion in Earth system models of relevant dynamics.

Straneo et al. say an understanding of the dynamic response of the glaciers on Greenland to climate forcings constitutes a scientific and a technological frontier, given the challenges involved in obtaining the appropriate measurements from the marine termini of the glaciers, and the complexity of the involved dynamics, including the coupling of the ocean, atmosphere, glacier, and sea ice systems. Crucial factors in making progress on this novel and complex problem are interdisciplinary and international cooperation.

Sources & Further reading

1. Straneo, F., P. Heimbach, O. Sergienko, G. Hamilton, G. Catania, S. Griffies, R. Hallberg, A. Jenkins, I. Joughin, R. Motyka, W. T. Pfeffer, S. F. Price, E. Rignot, T. Scambos, M. Truffer and A. Vieli (2013). "Challenges to Understanding the Dynamic Response of Greenland's Marine Terminating Glaciers to Oceanic and Atmospheric Forcing." Bulletin of the American Meteorological Society 94(8): 1131-1144.