Niwa scientist Dr Andrew Lorrey undertook the annual end-of-summer snowline survey with Dr Lauren Vargo, of Victoria University in Wellington, and fellow Niwa scientist Gregor Macara on Thursday, during which thousands of photographs of glaciers were taken, which will be stitched together and used to create 3-D models.
That, in turn, will enable scientists to understand how glaciers are changing and how much mass they are losing, year on year.
Dr Lorrey said heat waves in 2018 and 2019 had done no favours for the South Island’s glaciers, and while there more snow had been carried over from last winter during this year’s survey, the ash from the Australian bushfires was prevalent.
"The effect of the ash, I think more work needs to be done on that.
"What you can expect with ash falling on to snow is that it’s dark, it’s going to absorb more heat, and with that you’re going to get more melt of the surrounding snow and ice that’s in contact with it.
"But, until scientists get up to the glaciers and actually measure vertically what’s happening with those glaciers, we don’t know yet."
Dr Lorrey said the remaining ash would be covered by new snow this winter and, hopefully, transform into compressed ice, to eventually become part of the ice’s history.
"But I guess unto itself, it is quite striking and also just looking at the changes in the environment and digesting what we’ve seen in the last two, five, 10 years even, in terms of the ... changes I’ve seen in the alpine environment, it’s quite dramatic."
Describing it as a "relatively good year" for glaciers, he said that was nothing more than a temporary stay and by no means a "turnaround".
"For our glaciers despite having what looks to be a decent year, it would take many, many, many, many decent years, in a long run, to even begin to undo some of the damage that we’ve seen in recent years.
"Unless there’s some miracle that humanity improves dramatically, in a very, very rapid
way ... We’re going to have fewer glaciers at the altitudes that were lower, that we were accustomed to seeing in the 1970s and ’80s.
"As the warmth increases, as the snowlines rise, we are going to lose some of that part of our alpine environment.
"It’s not going to be glacierised anymore, it’s going to be bare rock."
The group
however, was unable to see the terminus of the Fox or Franz Josef glaciers due to cloud cover on Thursday, he said.
While the South Island would still have glaciers for "some time to come", in time there would be fewer as part of the broader landscape, he said.
More than 3000 glaciers and about 53cu km of ice were part of the survey when it began in the late 1970s — most recent estimates indicated up to a third of the ice has since been lost.
