Camilla Rutherford

How to fix: Agricultural emissions

Agricultural emissions New Zealand’s biggest climate challenge is different from that of other nations: it originates in the stomachs of cows, sheep and deer. This is what we could do about it.

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It seems harmless enough. In a paddock somewhere in New Zealand, a cow burps. And no wonder: she’s busy digesting grass, which is no easy feat—you need four stomachs to get sugars out of cellulose—so she has a lie-down to let the grass stew awhile in one of them, her rumen. It’s a chemical reactor in there. The grass ferments, courtesy of specialised microrganisms called methanogens, which set about picking apart the complex molecules, producing methane and water in the process.

It’s slow work, so she gives the methanogens a hand by bringing up clumps of grass she just ate and chewing them a bit more. Each time she does, she burps some of that methane into the air. Over a normal day, she might release 140 grams of it, which would be just fine if there weren’t 6.3 million other dairy cows and 3.8 million beef cattle across Aotearoa doing exactly the same thing. Add 26 million sheep (18.3 grams a day) and 1.7 million farmed deer (31.5 grams a day) and New Zealand has a problem.

Too much methane is lethal to the climate, trapping up to 86 times more heat than carbon dioxide does.

The New Zealand Agricultural Greenhouse Gas Research Centre has pointed out that New Zealand’s animal-produced methane emissions do more to warm the climate than all our carbon dioxide and nitrous oxide emissions combined. The impact of methane in the atmosphere is like compounding interest: it mounts as time goes by.

Methane lasts only around 12 years in the atmosphere—but it’s so efficient at trapping heat that the climate system, thanks to inertia and various feedbacks, will take centuries to stabilise after its presence.

“Three hundred years after a constant flow of methane emission has started,” wrote Parliamentary Commissioner for the Environment Simon Upton in 2018, “the warming effect is more than twice as high as it is after 50 years.”

Which makes methane a logical target for climate action. The United Nations Environment Programme (UNEP) recently calculated that cutting global methane emissions by 45 per cent by 2030 would reduce peak temperatures by 0.3ºC over the following decade. That’s a lot when you’re trying to limit warming to 1.5ºC.

“Cutting methane,” says Inger Andersen, UNEP executive director, “is the strongest lever we have to slow climate change over the next 25 years.”

Methane from animals represents fully 43 per cent of all New Zealand’s greenhouse gas emissions—an order of magnitude higher than any other developed nation (it comprises, for instance, just 15 per cent of Australia’s climate footprint)—so you’d think this would be a golden opportunity to get some early, impactful runs on the board.

But no: the Government’s Zero Carbon Act specifically exempts animal-produced methane from its target of net-zero emissions by 2050. Instead, it calls only for reductions of between 24 and 47 per cent below 2017 levels by then. Remembering that methane is the greenhouse gas that keeps on giving, that target will still cause additional warming of 10 to 20 per cent by 2050, which will increase to 25 to 40 per cent by 2100.

Federated Farmers says a shortage of “tools in the toolbox” means the best its constituency can do is trim 10 per cent off its methane footprint by 2050.

New Zealand farmers have been a protected species since the earliest days of Parliament. The Emissions Trading Scheme (ETS) is a cap-and-trade system of carbon credits, each equivalent to a tonne of emissions. Polluters must buy credits on the open market, and if their emissions exceed their credits, they’re held liable. If there’s more pollution than credits, the market drives the price of those credits up until it becomes cheaper for a producer to cut their climate emissions.

Not all mammals emit the same amount of methane when they digest food. Pigs have body weights similar to ours but emit ten times as much methane. Diet plays a role, too—sheep eating grass burp up 11 times as much methane as pigs. However, cattle are the undisputed heavyweight champions of methane emissions, producing 700 times the methane output of humans per animal per year. Bear in mind that there are twice as many cattle in New Zealand as people, and five times as many sheep.

But 13 years after the ETS was introduced, farmers remain exempt from it, even though the forestry sector was bound by it in 2008, the energy, industrial process and transport industries in 2010, and the waste and synthetic gas sectors in 2013. Ever since the Lange government stripped away agricultural subsidies in 1984 under Rogernomics, our farmers have been the poster children of the free market: the open, unshackled economy. Their unarguable success in world markets is exhibit A in the argument for purging farm subsidies from global markets.

But here’s the thing: that success has come at immense environmental cost, and that cost is being paid by New Zealanders, every time the government stumps up for another lake or river cleanup, as well as by those industries already held responsible for their own climate pollution. We are, then, still subsidising New Zealand agriculture, and the Zero Carbon Act has set the stage for another handout, says the Sustainability Council: “The current exemption allows farm owners to avoid ETS charges on 35.5 million tonnes of carbon dioxide equivalents this year, where each tonne is worth around $36 at current prices. That amounts to a $1.3 billion-a-year cross-subsidy to agriculture from all other sectors.”

The government’s decision to go easy on methane emissions means New Zealand can now only buy its way to Paris Agreement targets for 2030. The Climate Change Commission estimates we’ll need to purchase some 43 million tonnes of carbon credits from overseas, at a conservative cost of $100 per tonne. That’s a $4.3 billion cost we could be investing instead in cutting domestic agricultural emissions. (Moreover, the Prime Minister has signalled that we should strengthen our climate targets, in which case credit costs would soar, says the commission, to as much as $20 billion.)

But how? Farmers say the only way they can practically cut their greenhouse gas emissions right now is to run fewer cows, and the commission agrees: its advice paper to the government calls for livestock numbers to drop 13 per cent by 2030.

That ignores a hard reality: some farmers, especially in the dairy sector, are up to their necks in debt. Collectively, dairy owes lenders around $37 billion, and the Reserve Bank says around seven per cent of those loans are “stressed”. Given many farm budgets are founded on maximal stock numbers, farmers have called for technological fixes for emissions, rather than destocking.

As the agricultural sector grows, methane emissions increase, and current mitigations—such as energy efficiency, managing nitrogen and waste—cannot keep up even when deployed widely. New technologies such as low methylene breeding and a methane inhibitor will not reduce emissions to 1990 levels on their own; it’s also necessary to explore alternative land uses.

Some farmers have shown already that it’s possible to stay profitable with fewer cows. Owl Farm is a joint research project between St Peter’s School in Cambridge and Lincoln University attempting to find a “sustainable profitable future within dairy” on 144 hectares near the college. A 2019 Interim Climate Change Committee report showed that, even as Owl Farm’s greenhouse gas emissions had fallen by eight per cent, its per-hectare profit had risen by 14 per cent—just by improving management practices. The report projected a further 21 per cent boost to profitability through reduced feed and lower stocking rates, and Owl Farm’s greenhouse gas emissions to fall another 13 per cent.

It’s long been known that some easy solutions are sitting on the nation’s farms, waiting to be seized. Back in 2018, the Biological Emissions Reference Group (BERG) calculated farmers could effortlessly cut methane by 10 per cent from 2017 levels—the target that has now become official—just by adopting best practice around feeds, fertilisers, breeding and stock numbers.

To a townie, some of it seems extraordinarily simple: a hectare of irrigated ryegrass, for example, needs around a quarter of a tonne of nitrogen fertiliser every year, while lucerne needs none. There’s a growing pool of livestock genetics on tap to breed animals, especially cows, that produce less methane in their rumens. Yet even this would seem too much: dairy giant Fonterra and its supply chain emits some 20 per cent of New Zealand’s greenhouse gases—the single-biggest source of climate pollution—yet its stated ambition for suppliers’ dairy farms is only that they don’t increase their methane emissions out to 2030.

Before farmers can tackle the climate footprint of their business, they have to know the size of that footprint. But practically none do, according to a 2019 Ministry for Primary Industries report, Climate Issues Facing Farmers.

“In summary, only around two per cent of farmers with livestock have an indication of the total greenhouse gas emissions from their farm, and one per cent has an indication of the per-animal emissions from their farm.”

In 2019, after fighting the Emissions Trading Scheme tooth and nail for 20 years, primary-sector players finally proposed a joint body with the government—He Waka Eke Noa, or the Primary Sector Climate Action Partnership—to manage agricultural emissions outside the scheme. He Waka Eke Noa starts by bridging that knowledge chasm, helping farmers get greenhouse emissions into their farm business and environment plans. By the end of this year, it wants a quarter of New Zealand farmers to know their annual greenhouse emissions, and 100 per cent of them by the end of 2022.

By 2025, every farmer in the country is required to have an emissions-reduction plan up and running, and be subject to some kind of in-house pricing scheme. If they don’t, the government has reserved the right to drag the agriculture sector into the ETS, contingent on their progress by next year.

Meanwhile, some look to the promise of a tech fix. Scientists are starting to suspect that those troublesome methanogens aren’t even necessary for digestion (though nobody knows whether a cow could function without any at all). Perhaps if we could make the whole rumination thing easier for the cows, they might produce less methane. That means finding less-taxing feeds, and so far, researchers have fed them brassicas, white clover, chicory, plantain and various silage recipes, but forage rape is the only one that’s shown much promise, reducing methane emissions by around 30 per cent, though only when stock is fed nothing else.

Fodder beet has, in some trials, cut methane by around 20 per cent, but again, only when it’s the bulk of an animal’s diet, and reductions have mostly been only temporary.

The next big thing in methane-busting fodder, some say, will come from the sea: Asparagopsis armata is a cold-water red seaweed that grows around our coast. Inside its glutinous fronds is a compound called bromoform, a natural enemy of methanogens. A University of California trial found that a red seaweed supplement reduced methane emissions by between 45 and 68 per cent. But there’s a problem: bromoform is, according to the United States Environmental Protection Agency, a “probable” human carcinogen. And it eats ozone. Farmers fear a consumer backlash should traces of bromoform be found in exports.

An anti-methane vaccine would arguably be the easiest fix of all: a farmer would simply have to give the cow a shot every now and then without needing to tinker with feeds or farm systems, and a vaccine would leave no residue in meat or milk. It would work on sheep as well. A 2018 BERG report was bullish about a cow vaccine, expressing “medium to high confidence” that it would deliver a 30 per cent reduction in biogenic methane emissions by 2050.

Tim Rutherford inspects the roots of a brassica being trialled as an alternative feedstock on his Tarris farm. The stakes are high in finding a solution. A failure to bring agriculture into the ETS, says the Sustainability Council, means New Zealand will have to buy carbon credits to meet its Paris climate commitment—a cost to taxpayers of an estimated $1.3 billion.

It’s difficult to see where that optimism comes from. Despite a $2 million annual budget (admittedly, a pittance in vaccine research terms), and years of work, trials on sheep have delivered little. In a test tube, vaccine antibodies readily bind to methanogens, and do seem to impede them. But they’ve yet to work in a real rumen. The work continues: researchers at AgResearch Grasslands near Palmerston North are sifting through thousands of combinations to find some protein that might give the antibodies the help they need to stifle methane production.

BERG, for some reason, also declared “high confidence” that some alternative fodder would also bring about a 30 per cent reduction in biogenic methane by 2050. Putting aside the scarcity of encouraging results, there’s the plain reality that we just don’t have that long. “We can’t achieve the linked goals of healthy people and a healthy planet by incremental improvements to existing systems,” writes business commentator Rod Oram in Climate Aotearoa. “They are too broken, their damage is too great, and our time too limited.”

We can no longer pin our hopes on tech fixes yet to exist—not when farming practices are already available to us that would deliver real emissions cuts instead of prophesied ones.

Regenerative farmers work to restore their farms as self-sustaining ecosystems by eschewing inputs like artificial fertilisers and agrichemicals. They like to say that they farm soil, not animals, and a large part of the ethos is about returning carbon to the soil, instead of the atmosphere. They encourage a broad botany of pasture fodder and crops.

Most of all, they farm within limits, which means keeping stock numbers modest, instead of maximal. Right now, perhaps only five per cent of New Zealand farmers tend their land this way, but a groundswell is building. There’s little research yet to prove that regenerative farming conclusively reduces emissions, but the likelihood is so strong that it’s backed by some heavy hitters: the Our Land and Water National Science Challenge and NEXT Foundation have formed a research partnership part-funded by the Ministry for Primary Industries. The Pure Advantage research charity and the Edmund Hillary Fellowship have together launched Our Regenerative Future, a project to encourage a “science-led transition to environmentally sustainable agriculture”.

Before too long, New Zealand farmers may well find that the choice to abandon intensive, high-input, climate- and water-polluting farming is no longer theirs to make. Increasingly, consumers may make it for them.

In 2020, a Euromonitor report estimated that 42 per cent of all consumers globally are now “flexitarian”, following a largely plant-based diet that still allows for occasional meat meals. Fully 54 per cent of those consumers are Generation Z—the food buyers of the future. Most go flexitarian for health reasons, but many are increasingly concerned about the environmental cost of the food they eat.

New Zealand’s food producers have at once the most to lose, and the most to win. “The opportunity for New Zealand is in manufacturing high-value plant protein foods,” declared a 2018 Plant & Food Research paper, “sourcing ingredient streams from trusted sustainable and diversified production systems that meet our future climate change challenges, and delivering premium products into the ‘flexitarian’ diets of our international customers.”

Oram wrote in Climate Aotearoa: “If most of our farmers transition to regenerative systems over the next 10 to 15 years, they will build ecological and economic resilience and establish this new competitive advantage, even over such farmers overseas. They will then have a deeply compelling story to tell to the world about their pivotal role in tackling the climate crisis; in improving the range, quality and volume of food produced here.”

They should probably get a move on. Ireland has a head start on us, aggressively pushing a sustainable brand into world markets, ahead of a concerted strategy to adopt regenerative farming as the nation’s food-producing MO.

Young, savvy consumers can see right through the “100% Pure” billboard, and they’re not going to wait for New Zealand agriculture to find its environmental conscience.

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