Heatwaves melt 17 pct of ice off Southern Alps glaciers in three years - study

New Zealand's last three summers have brought the most intense heatwaves on record, both in the ocean and the atmosphere.

These record heatwaves have dramatically affected our fruit-growing industries, environment, and wildlife. 

A new study shows heatwaves over the last three years melted 17 percent of the ice off the Southern Alps glaciers.

Warmer waters might be linked to the starvation and death of little penguins in the Bay of Plenty, as well as the bleaching of millions of marine sponges across the north and south of the country.

The heat brought Central Otago's summer fruit harvest forward by up to two weeks, which forced orchardists to adapt to remain profitable.

Simon Webb is in tune with the subtle changes to weather resulting from a changing climate because it's tied to his livelihood. He's the owner of Webb's Fruit, an orchard in Central Otago.

"We have seen changes in the climate that impact our business. I suppose the climate just getting a bit more extreme," he said.

The summer fruit harvest in Central Otago is happening five days sooner due to heatwaves and Webb said even that impacts his business.

"We do have to take a small hit on our profitability," he said. "If there's an oversupply, we've got to increase the demand somehow, and that [means] working with the supermarkets to get the right promotions in place at the right times."

The last three summers have seen the most intense ocean and atmosphere heatwaves on record, resulting in a major loss of glacial ice in the Southern Alps.

"Looking at the three recent ones, we've lost almost a fifth of the ice volume and since 1949 we've lost half of the Southern Alps ice volume," said study co-author Dr Jim Salinger.

Warmer waters are suspected to have caused bleaching and disintegration of millions of marine sponges, which play a critical role in the ecosystem.

"So they remove food and carbon particles that are in the seawater and they take it down to the seafloor and recycle it, which then makes it available for other things that live on the seafloor," said marine biologist James Bell.

Rising sea temperature is thought to be linked to the starvation and death of kororā, or little penguins.

"The marine heat wave has caused some fish stocks and fish species to move their distributions, and as a result, we think there might not be enough food for the penguins," Bell said.

However, New Zealand has no national marine monitoring plan and no long-term data makes it hard to detect change.

Heatwaves this intense used to be rare. The study's authors found the summer of 1934 was remarkably hot and human-induced climate change wasn't a factor.

But the last three summers saw the warmest months on record and scientists said there's no doubt that increased frequency and intensity is a result of climate change caused by humans.

The changes people like Webb see might not be noticeable to the rest of us, but researchers said these dramatic heatwaves will be considered cool compared to what we'd experience with 2C or more of warming, which is what the world's on track for.