Antarctic ice - growing or shrinking? NASA vs Princeton and Leeds etc

There's a new paper out about Antarctic ice, from H. Jay Zwally and colleagues at NASA. They report that over the period from 2003 to 2008, there was a net increase in ice over all Antarctica of 82±25 Gt/year. This paper looks to be based on a conference paper at a SCAR workshop back in July 2012 (though that doesn't explain why there wasn't data from the past six years in the final published paper).

These findings are different to the results of work reported earlier this year from two scientists at Princeton, Christopher Harig and Frederik J. Simons. The Princeton team found that over the period January 2003 to 2014, there was a loss of ice overall. the overall mass loss from Antarctica since January 2003 at 92 ±10 Gt/yr.

It's also different from the results reported in a paper by Malcolm McMillan and colleagues last year. They estimated the current mass loss over all Antarctica at 159 ± 48 Gt/year. ".

So one group of scientists find that ice has been on balance increasing, while others find that ice has been on balance decreasing.