Two very different photos of Franz Josef Glacier taken from the same spot 13 years apart have highlighted the urgent need for climate action for a local geologist.
The first, taken in December 2007, shows Kā Roimata o Hine Hukatere reaching right down to the valley floor; but in the second, snapped just a few days ago, you can barely see the glacier at all.
"When I saw the glacier I was shocked to see how much it had retreated since I last visited with my father in 2007," geologist Christoph Kraus, who works for an engineering consultancy in Wellington, told Newshub.
"I knew it had retreated over that time, but it was still surreal to see it in person... Visual comparisons like these clearly show that we need to take urgent action to mitigate climate change."
Staff at Franz Josef Glacier Guides told Newshub the size of the glacier doesn't really change between December and February, so the fact the two photos were taken at opposite ends of summer isn't important.
Kraus shared the photos on his Instagram account.
"I had a very similar experience last year... sad you can barely see it now," responded one follower.
"I remember me standing in front of the glacier in 2008, looked pretty much like your 2007 photo - terrible what climate change is resulting in," said another.
At its maximum extent, Franz Josef Glacier is about 12km long. It advances and retreats over the years following fluctuations in the local climate, but since 2008 has been rapidly retreating.
It's lost 800m in length since Kraus last visited, and is about three kilometres shorter now than it was in the 1880s. Each advance it makes is usually followed by an even greater retreat. Computer modelling a few years ago suggested at current rates of warming, by 2100 it could be eight kilometres shorter and "unrecognisable".
Seven of New Zealand's warmest 10 years on record have occurred since 2008, NIWA data shows.
Kraus doesn't think New Zealand's small size should preclude it from doing its bit to fight climate change.
"Any bit helps. I actually think New Zealand is in a unique position to be a global leader in making significant changes to combat climate change if we take bold actions at all levels - Government down to individuals."
