We assessed area and volume of glaciers in the Ak-Shyirak massif in 2003 and 2013.

In 2003–2013 the glaciers lost 0.59 ± 0.34% a^− 1, twice the rate of 1977–2003.

Summer warming and open pit mining appear the main drivers of glacier reduction.

Mining accounts for only 7% of the glacier area and 5% of the glacier volume loss.

Slope-dependent models underestimate ice thickness in glacier headwaters.