The Government’s proposal for a Zero Carbon Bill has exposed an argument between scientists about the importance of methane. But it’s not really about science, as Eloise Gibson reports in this deep-dive news feature.

There’s beef in the world of methane.

Like a piece of marbled Wagyu, it is probably quite healthy — if consumed in moderation.

The argument is over when and how much New Zealand should reduce the methane from cow and sheep burps, which make up almost a third of our emissions, as we currently record them.

On one side is David Frame, director of Victoria University’s Climate Change Research Institute. He says we shouldn’t pressure farmers to cut livestock methane until we’ve got a bigger bogey, carbon dioxide, under control. Even then, he’d be content to keep methane flowing at its current rate or make very gentle cuts.

On the other side are several other prominent New Zealand climate researchers and scientific heavyweights. They say every molecule of methane heats the climate and the more we’re able to cut it, the better.

It might seem like an argument only climate scientists would care about. But the outcome may help shape the government’s planned Zero Carbon Bill and the rolling targets that will be set by a climate commission.

A very strict methane target could change the face of New Zealand’s $20 billion meat and dairy export industry.

A very light one might mean farming-as-usual.

While cowboys duel with pistols at dawn, climate researchers battle using charts and graphs attached to terse-but-polite emails. People on both sides are vying for the ears of policy-makers and any journalist who ventures into methane territory risks being cc’ed on group arguments.

Ordinary people are, understandably, confused.

Photo: Sir Peter Gluckman 

Take this string of numbers: In August, the Parliamentary Commissioner for the Environment, Simon Upton, issued a report saying 10-22 percent cuts to methane would be needed by 2050 to stabilise New Zealand livestock’s contribution to climate change.

In September, Sir Peter Gluckman put out his final report as Jacinda Ardern’s chief science advisor, which said there were “many reasons for acting aggressively” on animal gases, adding that calls to put less emphasis on methane were “counter-productive”. (That stung. Frame emailed Gluckman asking: why?).

In October, an IPCC report said countries needed to cut methane by 35 percent by 2050, to stay within 1.5C warming.

Then the submission-writers had their say: 91 percent of long public submissions on the proposed Zero Carbon Bill favoured getting all gases, including methane, to net zero.

A little confusingly, almost a third of those people went on to say they’d be okay with some ongoing methane emissions, provided there were “significant” cuts.

Meanwhile Frame was writing op-ed articles, explaining why he thought everyone else was being too hard on methane. He’d support anywhere between 0 and 25 percent reductions by 2050, he says, but he’d prefer a soft start followed by a stricter cut if new technologies come off.

The flurry of views made people think there must be scientific disagreement. “Which PhD is right?” quailed Federated Farmers’ climate change spokesman Andrew Hoggard after the IPCC report.

But it turns out this beef is not about science. The numbers aren’t contradictory, they just measure different things. The hard part is picking a target. And that turns on how you, ahem, frame the science.

Swamp gas

A quick recap: methane comes from rice paddies, coal seams, wetlands, cows’ stomachs and other swampy, airtight spaces. In New Zealand, it mostly comes from cow and sheep burps, which gives methane targets potential to pit city against country people.

Methane doesn’t cause much angst in most developed countries, since carbon almost totally dominates their greenhouse gas ledgers. But New Zealand’s high number of ruminant animals per capita makes us the highest per-capita emitter of methane. Methane makes up around one third of our emissions, as they are currently accounted for internationally. There is another greenhouse gas from farming, nitrous oxide, but it barely features in this argument because both sides agree it should be treated the same as carbon dioxide. And, while some countries have stemmed methane at no cost just by plugging natural gas leaks, cutting methane from animals is a trickier proposition. Doing so requires taming their gut microbes, which has proved challenging.

If you’ve had a beer with a switched-on farmer lately, you’ve probably heard that methane is short-lived. It’s true, at least on geological timescales. Methane mostly disappears from the atmosphere within a decade or two, although it leaves some lingering effects. (How big these are is a matter of slight disagreement). That makes its lifetime short compared to carbon dioxide, which is basically immortal. But while methane remains in the atmosphere, it’s potent.

It’s easy to think that temperatures are on a one-way trajectory up, and, with CO2, they are, because releasing carbon dioxide locks in warming for centuries. But with methane, if the flow stops, so does most of its warming. Cutting methane emissions (along with obliterating CO2) could cause temperatures to fall, or at least rise less than they would have. The effect would be similar to taking carbon out of the atmosphere, as scientists hope to one day do with carbon sequestration.

Common turf

Frame and his opponents share a lot of common turf. Here are some uncontroversial points:

(Conflicting charts can be addressed to the editor at Newsroom).

1.  CO2 is a much bigger climate problem than methane and there’s much more of it. It needs to fall to zero to avoid catastrophic climate change involving temperatures of 3C, 4C or 5C higher or worse. If we don’t tackle carbon, as one researcher put it: “Methane scarcely matters because we’re all going to hell in a hand basket anyway.”

2. No-one wants to go to hell in a hand basket.

3. As well as making deep and urgent cuts to carbon we could reduce peak temperatures (and cool things down a bit along the way) by cutting methane. But methane needn’t fall to zero. (This is lucky because it would make farming difficult. Rice and lots of other farm animals make methane, too, just not as much as cows do).

4. The constant flow of methane we produce with human activities keeps the planet consistently warmer (maybe in the order of 0.25C to 0.4C warmer) than it otherwise would be. Stabilising or making small cuts to methane would be enough to stop temperatures rising further, if COhit net zero. Making deeper cuts to methane would take away some of the warming it is causing now, aka cool things off. 

5. None of this come across very well in the methods countries often use to compare greenhouse gases (called GWP100). This exercise involves pretending each gas’ effects are spread over 100 years and converting each gas to CO2-equivalents. On that measure, a unit of methane is about 31 times worse than a unit of carbon. But that doesn’t tell you much about what methane does to temperatures. Researchers on both sides are devising and using alternative metrics to do this better, and those are the basis for their views in this story.

Different Frames 

This is the point where Frame starts to diverge from many of his colleagues. By the way, he knows he’s making his contemporaries grumpy, and, yes, it’s a bit uncomfortable. “There’s a lot more grief than there is high-fiving,” he says. “I know I’m irritating people and I don’t enjoy that.”

For the record, Frame says he doesn’t get any funding from agricultural interests. Beef & Lamb NZ bought him two pints of IPA and a flat white when they met him to discuss methane and that, he says, is about the extent of the farm industry’s largesse. “I’ve felt like I’ve had to pipe up because, if I don’t, who else is going to?” he says. “I’ve felt like there was research missing from official positions.”

Frame is a former Senior Research Fellow at the Smith School of Enterprise and the Environment at the University of Oxford who once led New Zealand’s climate change-themed Deep South National Science Challenge.

The research Frame highlights models what happens to temperatures if people make cuts to various gases. If people cut methane instead of cutting carbon dioxide that would be a mistake, he says, because it leaves the planet warmer, long-term. If they cut both gases, the cuts to methane would help lower the peak of global warming. But there’s little benefit to making cuts early, because long-term the temperature ends up the same regardless of whether the methane is cut now or in 20 years’, he says. And, no matter what we do with methane, CO2 determines most of the temperature rise. “If you stabilise the methane and get the two long-lived gases (CO2 and nitrous oxide) to zero, you basically stop the warming,” he says.

What Frame takes from this is that we aren’t taking carbon dioxide nearly seriously enough in New Zealand. He acknowledges that the Productivity Commission and others have started trying to map a path to carbon zero. But based on our current efforts (rising transport emissions) he thinks the idea that carbon will fall to zero by 2050 is “Pollyanna-ish”.

Frame says it doesn’t make sense to pressure farmers to cut methane until we’re well on the way with carbon. “At this point it is really about stopping the growth of CO2so why not stop pretending it’s about anything else and get on with that?” he says. “Where is the plan?” he says. “Once you have that, yes, let’s talk about methane.”

His opponents agree that COmust fall to zero, though they don’t see any obstacle to cutting methane as well. But Frame thinks focusing on methane has an opportunity cost. “If I thought people were sincerely on board with the CO2 point then sure,” he says.  “I don’t see it.”

This brings him to a sore point about funding, and what he thinks it has done to this debate. He thinks our policy-makers are receiving advice that blames methane too much for things. They’re hearing the correct science, he says, but it’s being phrased the wrong way. “Yes we all agree CO2 is really important but I feel like that’s in little 8 point font at the beginning of the sentence and then in 42 point font BUT WHAT ABOUT METHANE?,” he says. “It’s the way the New Zealand conversation goes.”

“There’s a strong willingness to emphasise the badness of methane but anything that might count in its defence is not shared so widely,” he says. “I think it has to do with the urban/rural divide.”

Frame’s complaint about funding is that in the decade to 2019, governments allocated $48.5 million to the New Zealand Agricultural Greenhouse Gas Research Centre (NZAGRC), a hub that co-ordinates scientists’ efforts to cut methane and nitrous oxide. There’s also been additional money for a global project that we launched with the United States a decade ago. While there are funds that carbon-focused researchers can apply for, we’ve assumed that other countries would put the big bucks into carbon-cutting tech, says Frame.

Frame thinks that was a mistake. “If agriculture is the only thing you invest it in will be the only thing you’re good at,” he says. “Why not tidal power or smart grid management?”

Frame goes further – he thinks that methane-specialists get too much air-time with policy influencers in Wellington, because of their strong government investment. It irks him that people like Gluckman don’t consult someone like him who’d give them an alternative view on methane. “I would have loved the chance to talk to Peter Gluckman,” he says.

Frame doesn’t blame the NZAGRC; it’s their job to focus on methane. But he wishes there was a carbon-equivalent: “Where is the analogous organisation like the NZAGRC to mitigate CO2, because if you had it there would be a voice for it and it could irritate all the people I’m irritating,” he says. “It would save me a job.”

Frame didn’t see a strong counterpoint on methane, so he decided to become it. Hence his volley of op-eds.

The case for cuts 

Other prominent climate researchers, both methane specialists and others, find Frame’s views a little puzzling.

“Every bit of methane emitted keeps the world warmer than it would be without that methane. That’s unambiguously true,” says Andy Reisinger, the deputy director of the NZAGRC. Reisinger is something of a go-to farm gas expert in Wellington, so you might describe him as Frame’s main adversary, were this not such a polite and personable battle (remember, climate scientists fight with graphs only).

Both men agree that their science is mostly compatible.

“It’s about emphasis and priorities,” says Frame.

“On the science, you’d hardly get a sheet of paper between us,” says Reisinger. “It’s how you frame the science.”

How Reisinger frames it is like this. He says that if politicians seriously want to stay within 1.5C or 2C of warming: “We cannot reduce Co2 rapidly enough to remain within that kind of temperature limit, [so] we’d need to reduce emissions of all gases and even more urgently with methane emissions,” he says. “They don’t have to go to zero, because any reduction is good, but the more we can reduce methane the better from a climate perspective.”

Martin Manning, the former director (before Frame) of Victoria’s University’s Climate Change Research Institute, agrees. “I’d use the analogy of the medical profession,” says Manning. “If you tried to get them to prioritise one aspect of human healthcare they’d just laugh because you can’t do that,” he says. It’s the same with carbon dioxide and methane, says Manning. “It’s not one or the other. You’ve got to look at everything,” he says. “If a dairy farmer’s feeding practices for his cows can reduce emissions, he can do that in parallel with bringing in electric cars faster.”

Suzi Kerr is an economist specialising in climate change at Motu. She agrees with Frame there could be more funding for carbon dioxide-cutting techniques, although she doesn’t think a single NZAGRC-like entity would work. “There are obvious things that could be researched in New Zealand…for example we might be one of the first countries in the world to go genuinely zero emission for our electricity and that’s not something other counties have had to do yet. Working out how to convert our steel production to zero emissions – someone needs to work out how to do that.”

Kerr also agrees that urban people have been blaming farmers for emissions – and it’s been counterproductive. “I agree that urban New Zealand has had a big thing about dirty dairying and there is a whole lot of emotion around that, but there is also a reality to it as well,” she says. “Yes, we need to do something about biological emissions, but people talk as if it’s the farmer’s fault and the farmers feel terrible,” she says.

But Kerr says that just because the rhetoric is blaming, it doesn’t mean farmers have been unfairly targeted. “We have had all of the energy and processing emissions in the emissions trading scheme for the last 10 years and we have done nothing on methane and nitrous oxide emissions,” she says. “Yes, there was a period of about five years when the [emissions] price was almost nothing. But increasingly firms are thinking about it,” she says. “The agricultural sector has been behind that because they have mostly been in ‘fight regulation’ mode.”

While many farmers have been resistant, Kerr thinks they’d be better off if New Zealand as a whole started finding ways to shrink their emissions now.

Some 23,000 households live and work on farms, and finding ways to change their practices without bankrupting or blaming them is a major exercise, she says. “We need to move on to more useful conversations because [the methane debate] is becoming another distraction,” she says. “Dave Frame presents this as we either deal with CO2, or we deal with methane, as though there’s a fixed amount of effort we can make,” says Kerr. “But…it’s possible we will do more on both. And if we reduce [methane] now, it would have immediate impacts on current temperature and temperature over the next 15-18 years.”

Kerr thinks that the last point, about temperatures, is crucial. Carbon is equally bad over all timeframes. But methane uniquely affects the short-term. Frame argues that methane can wait because making cuts in twenty years has the same impact on peak temperatures as doing it today. But Kerr says that misses something: “It’s not just peak temperature that affects people. It’s temperatures along the way,” she says. “We have to think, when do we think humans are going to experience the worst damage from climate change? It could be when the climate has heated the most. But it’s also possible that it will be in the next 20 or so years, when there are a lot of very poor people living in developing countries without the ability to adapt,” she says. “Maybe in 30 years they can cope because they have air conditioning and a stable society,” she says.

“We will have worked out how to retreat better from the coast, we will have better systems for managing extreme events, we may also find carbon sequestration and storage that’s cheap…I wouldn’t rely on it, but some people are optimistic.”

There’s one more issue about methane. Manning, a methane researcher, has concerns about the gas itself and the assumption it moves through the atmosphere quickly. “We are stressing the natural systems that [remove methane] for us,” says Manning. “If you’re stressing those natural removal processes, everything counts.”

Methane gets removed from the atmosphere by natural detergents, called hydroxyl radicals. IPCC climate models have always assumed that this self-cleaning process runs at a certain pace. But two unexplained spikes in methane led scientists to wonder if this atmospheric cleaning might be slowing down, for reasons linked to global warming. Manning says there’s increasing evidence that this happening, though he and other researchers are still trying to confirm it. “One of the reasons why you can’t ignore methane is that, although we don’t exactly know what’s going on, it’s going up at very fast rates,” he says.

Merely flattening methane could work, says Manning, if people cut CO2 very quickly. However: “If we push the whole system to the point where the natural controls for methane are no longer keeping up, we are really going to have to hit methane harder. We won’t know for probably 5-10 years just how bad this is.”


The climate doesn’t care about the cost of cutting greenhouse gases, but inevitably cost is in the background of all political conversations.

While scientists working under the auspices of the NZAGRC have made some significant findings, there’ve been no cheap, magical methane-stopping fixes. A hoped-for methane vaccine, as well as low-methane cows and low-methane genetically modified grass are works-in-progress.

Meanwhile, a Dutch company, DSM, has made an edible methane-shrinking compound, which the company will likely work with New Zealanders to try to adapt for our dairy cows. DSM’s powder cuts methane emissions by about a quarter. But until we have that kind of technology, deep methane cuts would need to come from changing land use, or carbon offsets. Good farming, such as breeding and farm management, can only reduce methane by an estimated 5-10 percent, says Gluckman. Normal productivity gains might shave off 22 percent by 2050 (based on the gains of the last twenty years), but only if we don’t increase dairy and meat production, says Reisinger.

The lack of easy options didn’t persuade Gluckman that we should back off methane. “There are no zero-emission strategies for biological greenhouse gases, yet there are many reasons to act aggressively to reduce their emissions. This goes beyond arguments of short-lived versus long-lived gases; there are also strong market and reputational reasons for driving down agricultural emissions,” he said in his report to Ardern, written with researcher Anne Bardsley.

Gluckman told Newsroom that consumers would move to alternative proteins faster than many people anticipated. “I think New Zealand faces a real threat that, if we remain a high methane producer per capita, it will be used against us by countries that can move into other ways (of farming) quicker,” he says. “The reality is that we live off selling food offshore and if the perception offshore is that our farmers are not making a contribution to reducing climate change there may be market resistance,” he says. “Freeloaders don’t tend to do very well, evolutionarily.”

But, while our reputation has value, our greenhouse targets will likely consider the domestic cost of burnishing it, by counting the cost of methane cuts. “If by 2050 we have a vaccine that costs 1c per animal and it reduces emissions by 50 percent, would it make sense to stick with only 22 percent reduction?” says Reisinger. “If mitigating methane was cost-free we wouldn’t be having this conversation.”


Exactly how much we can and should reduce emissions remains an open question. That’s despite what seemed like a series of competing reports on the topic this year.

Gluckman didn’t suggest any targets in his piece. Parliamentary Commissioner Simon Upton is writing a major report on farming emissions and greenhouse sinks currently, which will list some numbers and likely express a view. But he won’t be drawn into the quagmire of targets before it comes out in early 2019.

Upton asked Reisinger to take whatever tiny fraction of global warming was being caused by methane from New Zealand livestock, and calculate what would happen to that impact if we held our methane emissions steady. The intention was not to downplay New Zealand’s small slice of global emissions, but to find out what it would take for us to level off our impact (specifically, the impact of our farm animals).

Reisinger’s work showed that, if New Zealand kept producing the same amount of methane, the little slice of global warming that’s attributable to our livestock would be 10-20 bigger by 2050 than it is today (there are physics-related reasons why producing the same amount of methane would cause more warming over time). If we maintained the same emissions until 2100, our animals’ contribution to warming would grow by 25-40 percent compared with today, “which is quite a bit,” says Upton.

That skewered the idea that flat methane emissions would result in flat warming from methane. But the cuts needed to keep our contribution steady weren’t enormous: 10-22 percent by 2050. (Which end of the range is needed depends on how much other countries emit.)

Frame arrived independently at similar but slightly lower figures in a submission he wrote to the Environment Ministry: a 10-15 percent reduction by 2050 would hold our methane’s impact constant, he calculated. He told Newsroom he’d be happy with “anywhere from fixing methane emissions at today’s level (which would leave a little bit of warming) and reducing them by 20 to 25 per cent.”

People take different things from the numbers. Newsroom reported Reisinger’s figures for Upton as cuts that would give our cows a “clean climate conscience”. But the numbers don’t say whether ‘not worsening warming’ from our livestock is a good goal. Contributing no further warming merely means our livestock would continue to keep the planet hotter by the same tiny fraction they are responsible for today. Kerr describes it as a “random” thing to measure. “It’s become this real point of focus and it’s really farmers and sector bodies that, understandably, are looking for something that says they are not going to have to do too much.”

Reisinger says we need to ask what’s fair to other countries. “There are a lot of under-developed countries whose emissions must rise to give some space for development before they can come down again,” he says. “If all developed countries were saying ‘as long as we don’t add to further warming, we are fine’ that would leave 0.5C for all the developing world to reach the economic status that we have.”

Upton himself didn’t recommend a target, he just put the numbers out there. “I didn’t make any policy recommendations at all,” he told Newsroom. “I just wanted some good quality information.” He thinks the methane stoush is “a storm in a teacup”. “We know that…a reduction in the order of say 20 percent would put you in the ballpark of being able to say you weren’t adding to warming from the middle of the century onwards,” he says. That all he’ll say for now, except: “What I have said repeatedly is we have to do something about methane and nitrous oxide but none of that is a reason not to act much more vigorously on carbon dioxide.”

The IPCC posited deeper cuts than Upton’s numbers, because it had an ambitious goal — keeping warming within 1.5C. Unlike the simple methane-only exercise that Upton asked for, it modelled the cost-effectiveness and impact of cutting different gases for the whole globe, and looked at the interplay between gases. That’s was how the IPCC got a 35 per cent methane reduction by 2050, as well as getting carbon dioxide to zero.

You might expect that Frame would find 35 percent too high. But he found the IPCC report vindicating. “To me what it says is that even when you hit the brakes as hard as possible, harder than anyone thinks we actually will…you leave 65 per cent of the methane emissions.”


How hard people think we should combat methane partly depend whether they think people will act quickly on CO2. For people who don’t believe we’ll nail carbon dioxide, methane starts to fade into insignificance – after all, if carbon stays untrammeled, peak temperatures are a long way off and will shoot past 3C, 4C, or 5C regardless.

I ask Frame to put his Pollyanna hat on for a minute. If the government advanced a firm and credible plan for getting to zero carbon, quickly, would he be happy for New Zealand to also start now on cutting a quarter or a third off methane? “You’re assuming away the point of difference!” he says. “I would cheer loudly about the former, I would cheer about a plan to limit warming. But I would probably put the full stop there. And if we do stuff with methane too, yeah. Okay.”

And that is about as far as he’ll go towards mustering excitement about curbing methane. It’s because he cares about climate change that he wants us to put carbon first, he says. It’s never nice being at odds with your colleagues, but, then, robust discussion is a good thing, he says. Frame worked overseas for a long time and he thinks New Zealanders overrate consensus. “I think everyone’s trying to be constructive, even if we get a bit testy with each other,” he says. “People are trying to solve a problem and they are all trying to help.”

After all, this is the challenge of the century. The climate, and livelihoods are at stake. “We may believe each other mistaken but to me this is actually healthy,” says Frame. “Democracies should be contests of ideas.”

* People will have a chance to have their say on greenhouse gas targets in the Zero Carbon Bill during a select committee process, after the government introduces the bill to Parliament early next year. That bill may set a long goal, and leave short-term decisions to an independent Climate Commission. Right now, ministers are trying to win National’s support for the bill (as reported by Rod Oram)

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