In a recent calculation of how much ice has been lost from the world’s glaciers, New Zealand’s lack of measurements proved problematic for the researchers. Inés Dussaillant (from the University of Zurich) and colleagues combined manual glacier measurements with satellite glacier elevation data to derive annual changes in glacier mass for each of the glacier regions of the world since 1976. The work assumed a region’s annual glacier mass anomaly could be reasonably estimated from available manual measurements. In New Zealand there are only two glaciers with annual mass measurements, the Brewster and the Rolleston. To beef this up a bit the authors decided to add in data from the Martial Este glacier in the Argentinian part of Tierra Del Fuego. The next problem was that neither the New Zealand or Martial Este measurements extend back very far. To fix that, the study’s authors used the measurement record from Echaurren Norte, a glacier in Chile that has a record going back to 1976. Perhaps it should not be a surprise that New Zealand had the lowest score when the calculations were assessed for robustness by excluding one glacier’s data out of the equation. They removed the Brewster’s data, thereby leaving the Rolleston Glacier and the two South American substitute glaciers as the representatives for the Southern Alps.

Fortunately, the comprehensive assessment has been prepared in such a way that enables re-calculation as new data comes available. So when some additional New Zealand glaciers start being regularly measured, they’ll be able to be used, and the Chilean and Argentinian glacier substitutes will be able to be returned to the bench.