So the Antarctic land ice sheet might (for now) still be putting on weight overall, not loosing it? As a researcher says, though, this does raise an interesting question about the tricky field of sea level rise:
"The good news is that Antarctica is not currently contributing to sea level rise, but is taking 0.23 millimeters per year away," Zwally said. "But this is also bad news. If the 0.27 millimeters per year of sea level rise attributed to Antarctica in the IPCC report is not really coming from Antarctica, there must be some other contribution to sea level rise that is not accounted for."Anyhow, I'd be sure that there is more to come from Real Climate and others about this.
Update: here's a post at Hotwhopper that puts some perspective on this (including how it is a quite different different result from some other, recent work.) It's all to do with the complexities of using satellites that measure different things, over different periods. I would have guessed that the GRACE satellite that measures mass via changes in the gravity field would be the most reliable for working out the ice sheet balance, but this latest study (I think) doesn't use it.