Prime Minister Christopher Luxon. Photo: Marika Khabazi
Explainer - When asked this week about ACT's call to withdraw from the Paris Agreement on climate change, Prime Minister Christopher Luxon was quick to reject the idea.
Pulling out of Paris, the global accord to keep global warming below 2 degrees Celsius, would be "the quickest way" to hurt New Zealand farmers, he said.
"Our competitor countries would like nothing more than to see New Zealand products off their shelves. And I'm telling you, having worked in large multinationals, they would just move to another supplier anyway.
Luxon underlined that farming has been kept out of the Emissions Trading Scheme - a long-standing exemption - and said: "Very, very shortly, we'll have more to say about methane targets."
Those comments set the stage for the government's controversial proposal to adopt a new principle for methane: "no additional warming."
Lost? Here's what it means:
The great methane debate explained
New Zealand's biggest climate hurdle isn't coal or oil. It's cows. Or more specifically, the methane they emit - a greenhouse gas far more potent than carbon dioxide in the short term, and one that makes up almost half of the country's emissions.
Currently, the easiest way to cut methane is to cut the number of cows (and sheep and deer, who also produce the gas). But because cutting the number of cows could lead to lower milk production, and milk production is considered vital to farmers, business and the economy, managing methane emissions in this way is deeply unpopular among the farming community.
They're also deeply opposed to paying for their emissions in the same way other industries do, under the Emissions Trading Scheme, because it would impact profits.
That's where "no additional warming" comes in.
What is "no additional warming"?
Methane behaves differently to carbon dioxide. CO2 stays in the atmosphere for centuries, meaning even the strongest emissions reduction efforts can only stabilise its heating effect at today's levels.
Meanwhile, methane breaks down in around a decade. That means if emissions stay flat, the amount of methane in the air stops growing. In theory, that prevents further warming from methane.
Methane makes up almost half of the country's emissions. Photo: Adam Simpson
This is the idea behind "no additional warming". Instead of driving methane towards net zero, like with CO2, the proposal is to cut it just enough to hold its heating effect steady at a fixed point - in this case, 2017 levels, when New Zealand wrote its climate change targets into law.
Last year, a government-appointed science panel concluded that to keep methane's impact level with 2017, cuts of only 14-24 percent by 2050 would be needed. The current legislated target requires 24-47 percent.
The alternative
The Climate Change Commission (CCC), the independent body tasked with advising the government on emissions, says this isn't enough.
Methane is around 80 times more powerful than CO2 over 20 years. It doesn't linger as long, but while it's in the air it drives a huge share of warming. In New Zealand, it accounts for nearly two-thirds of the temperature rise the country has experienced to date.
Stabilising methane, scientists argue, therefore means "baking in" the warming we already have - floods and droughts included.
Farming is both a major cause of climate change and one of the industries worst-affected by the havoc it wreaks. Photo: Samantha Gee
Because of this, the CCC instead recommends deeper methane reductions of 35-47 percent by 2050. That wouldn't just stop methane making things worse, but actually cool the planet in the near term, buying time while the harder task of decarbonising CO2 plays out over decades.
It would also spread the cost of climate action more fairly across all emitting sectors, rather than leaving transport, industry, and households to do more.
Why farmers back "no additional warming"
Farming groups such as Federated Farmers and Beef + Lamb see "no additional warming" as a fairer goal. They argue that asking farmers to cut beyond stabilisation is like asking them to remove carbon dioxide from the atmosphere - a demand never placed on fossil fuel companies or industries that emit CO2.
The government has echoed these concerns, warning that pushing farmers too hard could drive production overseas to places with dirtier practices, a phenomenon known as "emissions leakage."
Supporting "no additional warming", they say, avoids harming New Zealand's most important export sector.
Why critics call it an "accounting trick"
Climate advocates, lawyers, and scientists view "no additional warming" very differently.
Lawyers for Climate Action call it a political choice dressed up as science - a way of sidestepping the CCC's statutory role and watering down climate ambition.
International scientists have been even more blunt, accusing New Zealand (and Ireland, which has floated similar ideas) of an "accounting trick" that allows high-emitting agricultural nations to lock in their current level of pollution as acceptable.
The result, they argue, is that the atmosphere stays hotter than it needs to be, while poorer countries and other sectors bear the burden of cutting harder.
Nestlé and Fonterra are collaborating to reduce emissions on New Zealand dairy farms. Photo: 123RF, RNZ / Rebekah Parsons-King
There are also reputational risks. New Zealand markets itself as a sustainable food producer, but companies like Nestlé are already pressing suppliers to show real climate progress.
Adopting "no additional warming", critics warn, could damage trade deals such as the EU free trade agreement and undermine the "clean green" brand.
The wider context
Ever since New Zealand signed the Kyoto Protocol in the 1990s, governments have floated ways to make agriculture pay for its emissions.
Farmers have successfully fought back, keeping agriculture out of the Emissions Trading Scheme and getting rid of a Labour-led scheme to introduce farm levies.
The "no additional warming" approach can be seen as the latest step in that campaign: by lowering the scale of required cuts, it would help protect farmers from higher emissions costs or herd reductions that would hit production.
What comes next
The government must decide whether to embrace the "no additional warming" principle or hold the line on the current, more ambitious cuts.
It faces pressure from farmers to lower the target, and from climate advocates - and its own independent climate commission - not to.
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