New Zealand glacier response to climate change of the past 2 decades

Oblique aerial photography of 111 glaciers during the past 2 decades has recorded a reversal of the past century glacier-recession trend. Cirque glaciers show little response to the recent mass balance increase; mountain glaciers show visible advances. Some valley glaciers have advanced, some have thickened in the upper trunk, and the larger ones and those with proglacial lakes continue to recede. The shift to advance is driven by an average lowering of snowlines of 67 m, equivalent to a cooling of 0.47°C if other factors are held constant.