Cyclones are getting so big that New Zealand is considering an extra category

Cyclones are getting so big that New Zealand is considering an extra category

Scientists may need to create a sixth category for cyclones as climate change creates more extreme weather events, according to New Zealand's Climate Change Minister.


Key points:

  • Minister says some category five cyclones could have a higher rating
  • Comments come as Pacific nations continue clean-up from Cyclone Gita
  • Expert says Pacific will be particularly vulnerable to climate change

James Shaw said there had already been category five storms that would have been given a higher rating if one was available.

A category five cyclone, as defined by New Zealand's MetService, has winds speeds between 215 and 230 kilometres per hour.

This differs from category five cyclones in Australia, which have winds exceeding 280 kilometres per hour.

Mr Shaw's comments at the Pacific Climate Conference in Wellington come as some New Zealanders affected by Cyclone Gita have been told it could take up to a year to clean up the region.

The storm devastated Pacific islands including Tonga and Fiji, before dumping large amounts of rain on New Zealand.

Cyclone Gita damaged or destroyed about 1,400 homes in Tonga.

Mr Shaw said scientists were linking extreme weather events to climate change and the stronger cyclones were challenging weather classifications.

One such storm was category five Cyclone Winston, the strongest cyclone on record, which killed dozens of people in Fiji in 2016.

"MetService experts tell me that it had much stronger winds than the 230 kilometre per hour upper-limit of a category five cyclone," he said, according to Radio New Zealand.

"The only reason it wasn't a category six cyclone is because we don't have a category six, but we might need one in the future."

Pacific vulnerable to climate change

Among the nearly 400 academics, scientists, policy makers and politicians at the conference in the New Zealand capital is American climatologist Michael Mann.

Dr Mann told the conference that climate change was happening at a rate that outstripped the predictions of many climate models.

"We're talking about a substantial increase in the risk of catastrophic coastal flooding and nowhere is that more apparent than here in the Pacific," he said.

"Climate change is no longer a theoretical problem, it's no longer some far-off distant threat."