Editorial: Marine heatwave spells trouble but we shouldn't be surprised

Last summer had some of the strongest marine heatwave conditions New Zealand has recorded. Photo / Alan Gibson, File

EDITORIAL

Scientists now warn average sea temperatures around New Zealand could rise by 1.4C within four decades – and almost 3C by the century's end.

If the pattern continues we could be experiencing 260 days of marine heatwaves per year by mid-century – and 350 days by 2100 – compared with the 40-odd days as is the case now.

Our seas have been warming by an average of 0.2C per decade – and the pace of heating is quickening.

For some regions, such as the southern tip of the South Island, recent Niwa-led research found a high chance that marine heatwaves could start to last more than a year.

Last spring, sea surface temperatures quickly rose to 1.1C to 1.4C above average – and more than 3C around some parts of the country, helping round out New Zealand's warmest year on record.

That marine heatwave is continuing in some places. Seas in the Bay of Plenty have been persistently warmer for the better part of a year. Marine heatwave conditions recently in the Fiordland region raised sea surface temperatures to 5C above normal.

We can agree with science on the causes - or look to the history of the planet for previous changes of such spectacular effect - but the fact remains that our activities are affecting the outcomes. And the consensus is that we are not doing enough about it.

Former prime minister Helen Clark issued a rare public admonishment to current officeholder Jacinda Ardern this week. "It's taken forever and we're really behind. We're talking the talk, but people need to see that we're stepping up," Clark said.

Herself raised in a farming community at Te Pahu, Clark said agricultural emissions in particular were a problem for New Zealand. Other countries are aware very little is being done on emissions reduction despite them making up about half of New Zealand's total emissions profile.

In a blunt speech to leaders gathered in New York this week, United Nations Secretary-General António Guterres said the global community was still not willing to tackle the "challenges of our age".

"We cannot go on like this," Guterres said. "We have a duty to act - and yet we are gridlocked in colossal global dysfunction."

Guterres also spoke again at length on the threat of climate change, urging wealthy nations to tax fossil fuel companies and divert the fund to those countries in need.

"Our world is addicted to fossil fuels. It's time for an intervention. We need to hold fossil fuel companies and their enablers to account," he said.

"The hotter summers of today may be the cooler summers of tomorrow."

Expect to hear more from the general assembly in the coming days but, once again, the conversation has been hijacked, this time by Russia's war in Ukraine and a global food crisis, partly as a result.

The ambitions of nations and leaders continue to carve rifts in any meaningfully unified action as the pot we are all in heats up.