[baobabaobab]

Sea levels are rising 2.6-2.9mm per year.

“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.”

Complete conjecture, but my money is on IPCCs estimates for other sources being a little too conservative, not some entirely new explanation.

[kpil]

Yes, interesting question.

(Other sources are what? Arctics? Heat expansion?)

Anyway, I particularly like that they are doing observations rather than just faffing around with models. Models are good, but data is better.

[baobabaobab]

The other sources are glacial melt, heat expansion, and water storage on land decreasing.

You need both the models and the data. Facts without theory answer only what happened, not why, you can't make projections without theory. Theory without facts... pretty obvious problem there.