New paper shows 'dramatic slow down of ice loss in southeast Greenland'

A paper published online yesterday in the Journal of Geophysical Research finds "the loss rate in southeast Greenland for the more recent period has become almost negligible, down from 109 ± 28 Gt/yr of just a few years ago. The rapid change in the nature of the regional ice mass in southeast and northwest Greenland, in the course of only several years, further reinforces the idea that the Greenland ice sheet mass balance is very vulnerable to regional climate conditions."  Global warming allegedly due to greenhouse gases would not be expected to cause such regional interannual variability in Greenland ice loss, thus pointing to shifts in weather instead.


JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 116, B07406, 11 PP., 2011

Interannual variability of Greenland ice losses from satellite gravimetry

Key Points:

This study shows dramatic slow down of ice loss in southeast Greenland
Glaciers in northwest Greenland dominate the ice loss since 2007
Greenland ice mass shows significant interannual variability

J. L. Chen et al

Using extended satellite gravity measurements from the Gravity Recovery and Climate Experiment (GRACE), here we show that ice losses in southeast Greenland appear to have slowed down dramatically since late 2007, while those in the west, especially northwest Greenland show continued accelerations in recent years. Over the period April 2002 to November 2009, averaged ice loss rates in eastern Greenland (120 ± 31 Gt/yr) are still significantly larger than those in the west (86.3 ± 22 Gt/yr). However, the estimated ice loss rate from glaciers in northwest Greenland has increased from 30.9 ± 8 Gt/yr over the first few years (2002–2005) to 128.2 ± 33 Gt/yr for the more recent period (2007–2009), while the loss rate in southeast Greenland for the more recent period has become almost negligible, down from 109 ± 28 Gt/yr of just a few years ago. The rapid change in the nature of the regional ice mass in southeast and northwest Greenland, in the course of only several years, further reinforces the idea that the Greenland ice sheet mass balance is very vulnerable to regional climate conditions. The dramatic slow down of ice loss in southeast Greenland observed by GRACE provides an independent verification of similar reports from other remote sensing data. The observed significant interannual variability of Greenland ice mass change suggests that it is very challenging to quantify Greenland's long-term ice mass change rates, and some observed apparent accelerations might simply be a reflection of the interannual variability.