The Greenland Ice Sheet
IPCC and other sources consider the Greenland Ice Sheet to be one of the main contributors to glacially-induced sea level change, along with the Antarctic ice cap and other glaciers/sea ice. The 2007 Fourth Assessment Report notes that “the Greenland Ice Sheet has also been losing mass in recent years” and suggests that its contribution to total sea level change is between +0.14 and +0.55 mm per year.
Results and Implications of the Greenland Glaciers Study
The study analysed a range of data for around 200 glaciers in Greenland over a ten-year period. Although there is considerable variation, lead author Twila Moon told Decoded Science that the scale and extent of the study are significant because “we have greatly increased our knowledge of how glacier speeds change. This knowledge is important for … making better prediction of future changes and the role those changes play in sea level rise.”
Despite the variations identified between glaciers of different types and in different regions, the overall findings suggest that, although the rate of acceleration (and consequent melting) of Greenland’s glaciers is increasing as the IPCC reported, it is not increasing as fast as had been feared.
Sea Levels Rising
The study did not provide all good news, however. “The bad news,” says Moon, “is that we are still seeing speedup…many previous researchers have suggested that sea level rise on the order of 1 m by 2100 is reasonable and our research is in line with these results.”
Moon, T., I. Joughin, B. Smith, I. Howat. 21st century evolution of Greenland outlet glacier velocities. (2012). Science, vol. 337, doi:10.1126/ science.1219985. Accessed May 3, 2012.
IPCC. Fourth Assessment Report: Climate Change 2007. Accessed May 3, 2012.
Wilson, R.C.L. et al. The Great Ice Age: Climate Change and Life. (2000). Routledge/The Open University. Accessed May 3, 2012.