A report out two days from polling day poses climate change questions for us all. David Williams reports
In May last year, Nelson’s City Council declared a climate emergency. It seemed to have good reason.
The Nelson-Tasman region declared a state of emergency after being battered by Cyclone Gita in 2018, and, a year later, on Waitangi Day, the Pigeon Valley fire led to another Civil Defence emergency.
Three months later – soon after the Zero Carbon Bill was introduced to Parliament – Nelson Mayor Rachel Reese asked councillors at an extraordinary meeting to support the recommendation to declare a climate emergency. The community had a “different voice” on climate change, she said – even from two or three years back.
“We’re going to need a new way of thinking and working to meet the expectations of our youth and of the next generation,” Reese said in a press statement after the meeting. (Three councillors voted against the motion.)
Nelson’s council was already measuring and reducing its corporate greenhouse gas emissions, and thinking about how to protect its infrastructure from sea level rise and rainfall intensity. It was starting to talk to residents about climate change and coastal hazards. “However, climate change-related work is likely to need to accelerate,” a council report to the extraordinary meeting said.
Nelson’s always been known as sun-drenched, with some of the highest sunshine hours in the country. Now, the city is revealed as one of the country’s places most affected by climate change.
A joint Ministry for the Environment (MfE)/Stats NZ report, Our Atmosphere and Climate 2020, released today, uses data from 30 environmental monitoring sites around the country, between 1972 and 2019, to show where climate change is hitting the hardest, and by how much.
(It’s too early to say what effect the Covid-19 lockdowns had on greenhouse gas emissions.)
Nelson topped the country for the fastest rate of annual average temperature increase – an average rate of 0.29 degrees Celsius per decade, ahead of Reefton, on the West Coast, and Canterbury’s Tara Hills, near Omarama.
Despite last year’s fire, Nelson’s days of very high to extreme fire danger is very likely decreasing. But, clearly, big fires are still possible.
Nelson featured in the top three for plenty of stats – rapidly warming winter temperatures (0.35°C per decade), fastest increase in annual average maximum temperature, and declines in frosty days (an average loss of five per decade).
The summer of 2018 was unprecedentedly hot. Average summer temperatures were more than 2°C above the 1961-1990 baseline at 11 of the 30 sites, including – you guessed it – Nelson. (In January of that year, Invercargill had three consecutive days above 30°C, and Cromwell’s average maximum temperature between the 19th and 31st of that month was 33.1°C.)
“The climate is warming, and changes are projected to intensify,” MfE deputy secretary for the environment Natasha Lewis says. “We can expect increased flooding in wet areas, more droughts in dry areas, more days of extreme fire danger. How much further change we can expect depends on the amount of greenhouse gases added globally to what already exists within the atmosphere.”
“This report demonstrates that climate change is not a far-off threat. It is affecting us and our environment in profound ways, here and now,” – Natasha Lewis
The trend is clear.
Last winter was the warmest on record. Earlier this year, Auckland experienced its longest dry spell of 47 days. (On average, between 1960 and 2019, our biggest city’s dry spells lasted 10 days.) An alarming disintegration of Southern Alps glaciers has set some on the path to extinction.
Climate scientist Gregor Macara, of Crown research institute NIWA, part of the report’s review team, says via the Science Media Centre: “I have been involved in writing New Zealand’s monthly climate summaries since 2013. In that time, for each location that has observed a near-record low monthly temperature, twelve locations have observed near-record high monthly temperatures.”
We don’t need a new report to tell us most of these things.
But, usefully, Our Atmosphere and Climate 2020 pinpoints climate change-related trends in those 30 chosen places. The report’s a synthesis of new data and insights since the last such report, three years ago.
(Seventeen are in the North Island – Kerikeri, Whangerei, Whangaparoa, Auckland, Tauranga, Hamilton, Rotorua, Gisborne, Taupo, Taumarunui, New Plymouth, Waiouru, Napier, Whanganui, Dannevirke, Masterton and Wellington – and 13 in Te Waipounamu, the South Island: Nelson, Blenheim, Reefton, Hokitika, Christchurch, Lake Tekapo, Timaru, Tara Hills, Milford Sound, Queenstown, Dunedin, Gore and Invercargill.)
Changes bring, to some places, more infrastructure-damaging rain storms, longer growing seasons as winter temperatures become more confined, and more energy-sapping or fire-inducing hot days. More generally, the rising ocean is becoming warmer and more acidic.
“This report demonstrates that climate change is not a far-off threat. It is affecting us and our environment in profound ways, here and now,” MfE’s Lewis says.
The report says rainfall’s changing, but in different ways in different places, showing the complexity of climate change.
A third of locations, many in the northern half of the North Island, had less rain, between 1960 and 2019. Southern South Island sites and the West Coast, meanwhile, had more rain.
The places with the biggest decrease in rainfall were Whangārei (4.3 percent per decade), and Tauranga (3.2 percent). The largest increases were experienced in Whanganui (2.8 percent per decade), Milford Sound (a 2.1 percent increase for what is the wettest of the 30 sites), and Hokitika (a 1.3 percent hike).
Those wetter places also experienced more intense rainfall – the kind of weather causing floods, landslides, road washouts – while in drier places, the rain was calmer, lazier.
Seasonally, more changes were felt in spring, and the fewest in autumn.
“It can take time observations related to climate change to be confirmed statistically,” deputy government statistician Rachael Milicich says. “For infrequent events, like extreme rainfall, it can actually take several decades for those clear signals to emerge.”
Timaru led the country for the biggest average increase in sudden downpours, 2 percent up per decade, followed by Kerikeri (1.6 percent) and Napier (1.5 percent). The place with the biggest fall in frequent downpours is New Plymouth, a decline of 1.6 percent per decade.
Masterton has the country’s highest increase (0.38°C per decade) in higher average maximum temperatures, while minimum temperatures are rising most quickly in Whangārei, Nelson and Gisborne.
Dannevirke’s average annual temperature was 1.73°C higher in 2013 than the 1961-1990 reference temperature – the largest anomaly of 16 comparable sites. Winters have changed markedly at Tara Hills, in Canterbury. Between 1972 and last year, the season warmed at an average of 0.41°C per decade – one of the highest rates of change of any site in any season.
Average winter temperatures increased at all 30 sites, while annual average temperatures increased at all but two of them. As it gets warmer, nearby farmers will have noticed their elongated growing season.
There were fewer frost days in many places. Whangārei hasn’t had a temperature below zero since 1994, whereas it’s very likely Lake Tekapo and Timaru have had more frost days each year.
Annual heatwave days increased at more than half the 30 sites. Warm days, in which the mercury climbs above 25°C, “very likely” increased at nearly 20 of the reference locations.
“We’ve all got choices to make and the action is required across the country.” – Dr Alison Collins
The report’s broad conclusions are well-known. (A big improvement on previous reports is the inclusion of stronger te ao Māori voices, and the link made between climate change and human wellbeing.)
Overall, New Zealand’s average annual temperature has increased by 1.13°C (plus or minus 0.27) since 1909. The country’s gross greenhouse gas emissions rose 24 percent from 1990 to 2018, with transport and agriculture creating our biggest headaches.
Global temperatures are expected to increase and, without dramatic cuts in greenhouse gas emissions (45 percent below 2010 levels by 2030), average global temperatures will go above 1.5°C the pre-industrial level, causing dramatic changes.
Climate research tells us the last time carbon dioxide levels were as high as they are now – was three million years ago. At that time, temperatures were 1.8-3.6°C warmer, trees grew in Antarctica and seas were at least 20 metres higher.
Each tonne of climate-changing carbon dioxide accumulates in the atmosphere, hangs around for thousands of years, and locks in a warmer world. By 2100, the world could be 3.4-3.9°C warmer, under current policies.
For New Zealand, that could mean warmer temperatures, with Auckland getting “warm days” (maximums over 25°C) four times as often by 2090. The Wellington region is predicted to get intense, extreme rainfall more often. Droughts will be more severe, killing native forests and increasing wildfire risk. Wellington and coastal Otago, in particular, are projected to experience more days of very high or extreme fire danger.
Rising sea levels and more severe storms will threaten coastal populations, as well as marae (meeting places), ancestral Māori urupā (burial grounds), and traditional mahinga kai (food gathering) customs, often involving taonga (treasured) species. That’s not to mention the island nations in the Pacific.
Under the Paris Agreement, New Zealand has committed to reducing emissions by 30 percent of 2005 levels by 2030. But under existing policies, the country is projected to hit 707 million tonnes of emissions, 18 percent higher than our emissions budget of 601 million tonnes.
The report notes the target can be “met” by buying international carbon credits, but, sadly, doesn’t forecast how much that might cost – an important factor when weighing up costly changes to reduce emissions.
Prescriptive responses to environmental effects aren’t part of the report – legislation prevents it. But, in its own gentle way, it points out the logic of acting early – “some interventions take a long time to have an effect”, it says, and “if left too late, the options can be limited and more costly”.
It’s not aimed just at politicians.
The report says it’s meant to be the basis for an “open and informed conversation” about what we have, what we are at risk of losing, and where we can make changes”. We’re all responsible, it suggests. “Our activities and the choices we make every day can produce or reduce greenhouse gas emissions. At all levels, from central to local government and businesses to communities, iwi, families, and individuals, we are continually making decisions that affect the climate.”
Asked about rising transport emissions, and our high rate of car ownership (the highest in the OECD in 2017), Dr Alison Collins, MfE’s chief science advisor says that up to each person. “It demonstrates that we’ve all got choices to make and the action is required across the country.”
MfE’s Lewis warms to the same theme. “It’s clear from the findings in the report that we need to act and we need to act now, and that responsibility falls to each and every one of us.”
She adds: “It will be up to the new government to decide what sort of policy response they may wish to pursue to the issues raised in the report.”
The election campaign has centred on the Covid-19 response and the economy, but there has been plenty of scrutiny on political parties’ climate-related policies. If even the most radical policies are adopted, it’s still unclear whether they’d go far enough, the emissions cuts would be deep enough, to meet our Paris Agreement target.
That leaves it to each of us – individuals, communities and businesses. How much warming do we find acceptable?
