First the good news. You shouldn’t need gumboots, a raincoat or even a canoe to leave the house next summer. Well, probably. For those fearing that climate change means this year’s appalling weather is New Zealand’s new normal, chances are it won’t be.
With rising global average temperatures expected to breach the crucial 1.5°C above pre-industrial levels as early as 2027, the increasing warming of the planet because of man-made greenhouse gases means more extremes in climate and weather around the world. But the headline for New Zealand from one of our most prominent climate scientists is that this year’s ruinous weather may just be down to rotten luck. Well, probably.
“My hope,” says James Renwick, doing his best to sound hopeful, “is this unfortunate sequence of events in the North Island so far this year is not going to be the norm in the future. I can’t be sure it won’t be, but there’s no real reason to think it will be. My seat-of-the-pants feeling is it won’t be.”
Seat-of-the-whatnots or not, Renwick has the expertise to make the call. He was a climate research scientist at Niwa, the National Institute of Water and Atmospheric Research, for 20 years. Now, he’s a professor of physical geography at Victoria University of Wellington Te Herenga Waka and a member of New Zealand’s Climate Change Commission. He’s also been a key contributor to the global Intergovernmental Panel on Climate Change since the early 2000s.
So any prediction Renwick makes should be listened to by those who are worried about where our climate and weather are headed – and that’s most of us. A poll of New Zealanders taken by insurer IAG last year found 75% of those surveyed said they were seeing, or were expecting to see, more frequent and extreme floods, while 72% thought they were seeing, or were expecting to see, more frequent and more severe storms.
If you are already expecting things to get worse because of climate change, it’s a natural assumption after disasters like the swamping of Auckland and the devastation of Hawke’s Bay and Tairāwhiti to expect such events to be our lot from now on. Although they probably won’t be, Renwick is clear that without worldwide action to decarbonise, climate change will fundamentally alter our climate, how we live and work, and reshape our world.
Still, there is some comfort to be taken from this year’s destructive events being likely aberrations, though those in the direct path may feel differently.
“I feel sorry for the people who were in the firing line,” says Renwick, who lives on the Kāpiti Coast. “I’ve never had my house flooded out. But it must be a terrifically dispiriting thing to have happen. And to have it happen again and again – awful.
“We have had a lot of those events this year, but I don’t think that’s a sign of climate change, it’s just a sign of bad luck.”
Wake-up calls
But here’s the terrible irony: disasters get our attention. Extreme events such as Cyclone Gabrielle are unavoidable even for those not directly affected, and they force us to think about what Renwick calls the “existential threat to global civilisation” caused by man-made climate change. “I wish it wasn’t this way. I wish we didn’t have to have death and destruction to get to that point.”
But it is the silver lining to all those goddamn storm clouds. As Renwick writes in Under the Weather, his book on what climate change means for New Zealand, he believes the more we talk about the issue, the more we care about it, and the more likely we are to do something about it. “I’m a big advocate for conversation being the most important first action anyone can take – to just talk about climate change,” he tells the Listener. “We hear a lot more about it these days than we’re used to because of all the extremes that are happening. Even so, it’s still not part of the everyday conversation that most people have. We need to be having those conversations.”
As a conversation starter for New Zealanders, Under the Weather should prove invaluable for those worried about the threat of climate change but still puzzled or confused about the mechanics. It’s divided into four sections: the first two survey what drives global climate and the peculiarities of our local climate. The second half of the book takes a shot at forecasting Aotearoa’s climate future, what the best- and worst-case scenarios are and, most importantly, what nations, communities and individuals need to do in the next decade to avoid catastrophe.
Renwick, who won the Prime Minister’s Science Communication Prize in 2018, hopes it will teach the reader how the climate works, helping them to understand the climate-change forecast both in the immediate and long-term future.
It is an FYI, but is it a cri de coeur [cry from the heart], too? “It’s definitely a cri de coeur. I am passionate about at least trying to make the future better for those who come after us.”
What Under the Weather isn’t is an activist’s manual. Rather, Renwick sees the book as a manual of solutions to inspire action on climate change. “The way I do that is to paint a picture of how bad it could be to scare people into wanting to do something, and then say, ‘Well, if we do this, this and this, here’s how good the future could be, so let’s get on with that’.”
Coming our way
So what should the fearful many (and the wilfully ignorant or uninterested minority, for that matter) expect for our climate’s future? The fact that Renwick has subtitled his book A Future Forecast for New Zealand suggests nothing is certain, at least not yet.
“I’ve spent my whole professional career forecasting either the weather or the climate. I know in my bones that nothing is certain. We can never be perfectly right in our forecasts, even of the next few hours, let alone the next few centuries. So, Under the Weather is a possible future for us – which is really about what are the possible futures for action on climate change.”
Forget Australia. New Zealand is the lucky country, at least when it comes to climate. Our nearest neighbour is, sadly, a good example of a place of climate extremes that will become only more acute as global temperatures rise. Melbourne and Sydney, for example, are already experiencing temperatures of over 40°C, and may face highs over 50°C before the end of the century.
New Zealand, meanwhile, is in a sort of climate sweet spot, thanks to its literal place in the world. We are right in the middle of the latitudes, and we’re surrounded by ocean which tends to buffer the climate and keep it temperate. “It’s a pretty variable place,” Renwick says. “We have ups and downs, wet and dry, hot and cold, which means the climate-change trends are a bit drowned out by the noise of the ups and downs in our regular climate.”
This is not likely to change noticeably over the next century. Which means it is very unlikely any part of New Zealand will be made uninhabitable as global average temperatures overtake the 1.5°C above pre-industrial levels set as a hopeful limit by the 2016 Paris Agreement, and towards an even more worrying 2°C.
That Aotearoa won’t be uninhabitable is about as encouraging as Renwick’s forecast for New Zealand gets, at least if the world does nothing or little to eradicate greenhouse gases.
Much less encouraging, if global warming isn’t halted, is that parts of Aotearoa might become more difficult to live in – though how much and how badly depends on what the world decides to do this decade.
Although warming here is expected to be a little less than the global average rate, rising temperatures will lead to the westerly winds that dominate our climate gradually increasing for at least the rest of the century, further warming the entire country.
Stronger westerlies will make the west of the country wetter, and the far north and east of the country drier. Renwick predicts that a couple of degrees of global warming could see a doubling or tripling of droughts in regions such as Canterbury, Hawke’s Bay and Northland. Land use and agricultural changes will be locked in by this, too, possibly for hundreds of years. Canterbury, for example, now dominated by dairying, will have to revert to drylands agriculture such as grain growing, and further south, winters may no longer be cold enough for stone-fruit trees such as apricots.
Drier, warmer days mean greater risk of wildfires, too. Though New Zealand won’t be Australia, in the east of both islands there could be a doubling or tripling of the yearly period spent with very high or extreme fire danger.
“I think there could be movement in populations, too,” Renwick says. “People might want to move out of dry places like Hawke’s Bay or Whangārei, for example, and go somewhere where it’s easier to get water. Water availability is going to be the big issue.”
Shrinking coastlines
Elsewhere, the issue is going to be what could be called an over-availability of water. Many thousands of homes and businesses, along with roads and other expensive pieces of infrastructure, sit within metres of the sea and are threatened by eroding coastlines from rising sea levels.
How high will the seas ultimately rise? As ever, it will depend. Sea levels around New Zealand have already risen 20cm in the past century, and Renwick says we are guaranteed at least another 30cm by around 2080. In many parts of Aotearoa, that will mean 1-in-100-year sea erosion events happen every one to four years.
But what happens to our sea levels in the next 50 years really depends on how much global action is taken to quickly reduce greenhouse gases. Renwick says if the world acts now, we could get away with a less-than-1m rise over the next century; if we’re unlucky, it could be 2m. But if the world’s average temperature rises by more than 2°C, it will lock in at least a 5m sea-level rise, putting downtown Auckland, South Dunedin and Lower Hutt under water.
Those not living near the coast won’t escape the deluge. Two-thirds of us live on flood plains, and the heavier rain events climate change is already delivering will mean we will face more frequent and more record-breaking floods – and the “rivers” above us will be mostly to blame. So-called atmospheric rivers are long filaments of moisture in the sky that can stretch from the tropics to the middle latitudes where New Zealand sits.
Renwick says a single atmospheric river can stretch thousands of kilometres and carry more water (in the form of gas) than the Amazon. And it is these rivers that are already causing serious flooding, including the Auckland Anniversary Weekend disaster that took four lives.
The larger amount of moisture in the atmosphere will also contribute to storms. Interestingly, there will be fewer of them, but their strength is another matter: Renwick predicts storm damage is likely to grow because of the wind and rain intensity created by the increase in atmospheric moisture.
Pacific cyclones will have a similar profile: fewer of them, perhaps, but more intensity in those that do form. How much more? We don’t yet know. But local and international scientists issued an “attribution statement” in March suggesting the worst storm to hit Aotearoa this century, February’s Gabrielle, dropped as much as 30% more rain because of climate change.
Missing the tipping points
There is a way to make this daunting forecast go away: stop burning fossil fuels. If we waved a magic green wand and woke up tomorrow in a zero-carbon world, Renwick says, we would not see a 1.5°C average increase in global temperatures after all, and the climate would begin to stabilise where it is now. But the world is not going to go to zero carbon tomorrow.
“Given the pace of change, we have locked in 1.5°C and probably a bit more than that,” he says. “But it becomes really important to know, are we stopping at 1.7°C? Or at 2.3°C? The higher the number goes, the more warming, the more risk, and there are thresholds and tipping points, especially around sea-level rise.”
How high average temperatures go is up to us, so the shape of the future is up to us, too. “The reality is this is a human problem and human institutions are going to have to solve these problems – and they usually operate very slowly. But the response to the Covid-19 pandemic gives me a bit of hope that when governments realise they’re in big trouble, they can take action very quickly, and people can go along with it.”
Only, the world’s governments aren’t responding to climate change in the way they did to the pandemic. In his book, Renwick says that while global leaders now talk a lot more about climate change, the global community still subsidises the fossil-fuel sector to the tune of hundreds of billions of dollars each year. Big oil is still in charge, he believes. “It staggers me,” he writes, “that there are business leaders and world leaders who are prepared to gamble with billions of lives for the sake of profit.”
He is more positive about our government’s response these past five years, which has included the passing of the Climate Change Response (Zero Carbon) Amendment Act in 2019 and the creation of the Climate Change Commission to provide evidence-based advice to the government.
“I’m really pleased that there is a start,” he says. “What I’m not so sure about is how quickly action will happen from here, but things are going in the right direction in this country.”
Interestingly, Renwick is less concerned about the emissions from our browbeaten agricultural sector than other industries, mainly it seems because, although methane gas produced by ruminant animals is much more potent than carbon dioxide at trapping heat in the atmosphere, it doesn’t last nearly as long as CO2, which will stay around for hundreds of years.
New Zealand’s biggest CO2 emitter in the past 30 years is actually the transport sector (that’s mostly individuals driving cars), followed by industry and energy production. So the “most urgent issue” is to decarbonise these sectors by moving to renewables as quickly as possible.
What’s stopping us? “It comes down to cost,” Renwick says. “To build a replacement for the [gas- and coal-fired] Huntly power station is very expensive. But treating such things as just costs is absolutely the wrong way to think about them. It’s an investment, and the pay-off is astronomical, because we are able to save the future.”
Under the Weather: A Future Forecast for New Zealand by James Renwick (HarperCollins, $39.99)
