The question has puzzled scientists: when the world's glaciers were retreating, why were New Zealand's glaciers getting bigger?\
New research from a group of New Zealand scientists may have solved the mystery, but it's not good news; New Zealand's glaciers are now likely to continue melting at a dramatic rate.
Between 1983 and 2008, when the vast majority of the world's glaciers were shrinking in a warming world, at least 58 New Zealand glaciers grew bigger.
The Southern Alps was one of a handful of areas internationally where glaciers were growing – In 2005, 15 of the 26 advancing glaciers worldwide were in New Zealand.
In that time, Franz Josef Glacier regained nearly half the mass it had lost during the 20th century.
The unusual period of advance came after several decades or rapid decline, which for many glaciers has resumed since 2008.
Many of the country's largest glaciers have retreated substantially since 2011 with several on track to disappear entirely.