New Zealand glaciers turn brown due to Australian bushfires

Snow and glaciers in New Zealand have turned brown after being exposed to dust from the Australian bushfires, with one expert saying the incident could increase glacier melt this season by as much as 30%.

On Wednesday many parts of the South Island woke up to an orange haze and red sun, after smoke from the Victorian and New South Wales blazes drifted east on Tuesday night, smothering many parts of the island for most of the day.

On Thursday, pictures taken from the Southern Alps showed the smoke haze carrying particles of dust had tinged snow-capped mountain peaks and glaciers a shade of caramel, with former prime minister Helen Clark expressing concern for the long-lasting environmental impacts on the mountains.

“Impact of ash on glaciers is likely to accelerate melting,” Clark tweeted. “How one country’s tragedy has spillover effects.”

There are more than 3,000 glaciers in New Zealand and since the 1970s scientists have recorded them shrinking by nearly a third, with current estimates predicting they will disappear entirely by the end of the century.

Professor Andrew Mackintosh is head of the school of earth, atmosphere and environment at Monash University, and the former director of the Antarctic Research Centre.

He said in nearly two decades of studying glaciers in New Zealand he had never seen such a quantity of dust transported across the Tasman, and the current event had the potential to increase this season’s glacier melt by 20-30%, although Mackintosh stressed this was no more than an estimate.

“It is quite common for dust to be transported to New Zealand glaciers, but I would say that the amount of transport right now is pretty phenomenal – I don’t think I’ve ever seen anything like it,” Mackintosh said.“It is concerning to me to see so much material being deposited on the glaciers.”

Mackintosh said the whiteness of snow and ice reflected the sun’s heat, and slowed melting. But when this whiteness was obscured the glacier could melt at a faster rate.

The higher glaciers around Mount Cook could likely get more snowfall soon, Mackintosh said, but the lower glaciers may not get another dump till March, and the dust would sit there until then, likely turning pink when algae began to grow.

The impacts of the dust event would likely last no longer than a year, Mackintosh said, but if Australia continued to be impacted by extreme wildfires and droughts “it will be one of the factors that is accelerating the demise of glaciers in New Zealand overall”.

The recent smoke haze drifting over New Zealand is the fourth such event this summer, the Met Service said, and despite no official health warnings being issued, many with asthma said they were choosing to remain indoors during the unusual conditions.

The Met Service said most of the smoke remaining over New Zealand would clear by Friday.

Early in December travel writer Liz Carlson took pictures of regions of the Southern Alps turning pink following exposure to smoke from Australia early in the bushfire season.

In a blog Carlson wrote: “It’s pretty remarkable to see the impact of the fires from so far away.”

“Our glaciers don’t need any more battles as they are already truly endangered; it puts the impact of climate change into even more stark reality we can’t ignore.”

Residents in Auckland and some parts of the North Island woke to an unusually bright orange sun on Thursday, thought to be a result of the bushfires 2,000km across the Tasman sea.

The Ministry of the Environment has been contacted for comment.