The night the floods hit Auckland, Climate Change Commissioner James Renwick was at home in Wellington, scrolling. When the first photos came up he thought he was looking at Bangladesh. “‘Oh it’s Auckland?!’ My mouth fell open. I just haven’t seen those sorts of images in this country before.”

It’s one thing to write a report predicting events like the floods and Cyclone Gabrielle, he says. Quite another to watch it happening.

“You can’t be certain that you’re absolutely right, you can’t prove it, you’ve got to wait for it to happen—but you really don’t want it to happen.”

Let’s dispense with the obvious. Of course it’s climate change. A redundant question, agrees Renwick. “Climate is already different. Every weather event, every sunny day, is different—even benign weather is different.”

Much as it’s human nature to cast around for patterns and certainty, he’d also like us to shelve the phrase “one-in-100-year storm”, and versions of. They’ve lost all meaning.

“If the climate’s stable it makes sense to say ‘Oh yes, this kind of event will happen on average every two years’ or something, but when both the average climate is changing and the variability of the climate is changing, then it’s pretty much impossible to really pin down the return period for any of these events.”

More of the bleedingly obvious: we have to stop burning fossil fuels, stat. We also have to roll out “serious adaptation plans, and I think that will involve shifting communities away from very risky locations. Such as beaches. Such as flood plains.”

John Cowpland, the Hawke’s Bay photojournalist who shot the Cyclone Gabrielle images on these pages, says if he lived in the region’s worst-hit areas, “I would be thinking exactly that: ‘Why would I bother trying to rebuild?’”

Eskdale, a bucolic valley of vineyards and lavender farms near the coast north of Napier, is one of those places. You can only see the tops of the vineyard poles there, he says. “It’s just all silt.” Quite different from the floods two years ago which left parts of Napier underwater. That was rain. This time it’s the rivers. “Obviously they snake their way through Hawke’s Bay… So for all of them to go at once—every one of them is bursting its banks or taking out the bridges.”

Pakowhai, a flat area of orchards near the coast between Napier and Hastings, is bordered by two of the big rivers, the Tutaekuri and the Ngaruroro. “Both of them have gone, so that whole plain in the middle has just become the river, heading out towards the sea.”

Cowpland got a drone up over Eskdale but as we went to press he hadn’t managed to get near Pakowhai. Bridges are gone, roads are gone; he’s been stuck in Napier for two days, chasing any fleeting patch of cellphone signal. He’s unable to properly do the job he loves, for the region he loves, and it’s eating him up. “Frustrating,” is the first thing he says, asked how it’s been. And: “It’s been humbling.” People have been good to each other. One woman packed her station wagon with bread and milk and quietly did the rounds. An older man hopped on his paddleboard to bang on doors of people he knew were housebound.

Unlike in Auckland, which braced for Cyclone Gabrielle while still wringing itself out from the floods, Cowpland says in Hawke’s Bay there was no mad dash for the supermarkets beforehand, no “Holy sh*t here it comes”.

That, in not so many words, could be Erick Brenstrum’s mantra. The former severe weather meteorologist with MetService (and a longtime weather columnist for New Zealand Geographic), has long been watching similar extreme events surprise countries all over the world.

He reels them off: “Flood in Naples 11 years ago where in the steep streets there was water a metre deep travelling at 30 kilometres per hour, with cars bouncing around like marbles. Fifty per cent greater than the heaviest rain they had on record. Majorca. One of the islands near Sicily last year.

“We had that absolutely horrific event in Western Europe last year, where the rivers gouged a huge trench out of parts of Western Germany and Belgium and Holland.”

It’s to do with the physics of our warming air, he explains: its increased ability to hold onto water vapour, the heat released when the vapour’s pushed upward by a thunderstorm or cyclone, the way that heat can make a storm “drop anchor” and rain, and rain, and rain.

“I often talk to people and say, ‘Look, the peak of the last ice age was only five degrees difference in global average temperature but the sea was 120 metres below what it is today—and we’re talking about the possibility of a three- or four-degree increase in global average temperature. That’s absolutely unthinkable.

“The weather can do worse than what we’ve just seen, and I’d be surprised if it doesn’t in my lifetime.” Brenstrum is 71.