Is methane vaccine NZ’s climate silver bullet?
Imagine investing 15 years of your life in something you know might never work. But knowing too that if it does, you could help change the world. And all from Palmerston North.
AgResearch scientists Peter Janssen and Neil Wedlock are doing just that, in the quest to design a vaccine that could cut the amount of potent climate-warming methane burped up by sheep and cows.
It’s one of many methane-reducing possibilities being chased around the world, from selective breeding to daffodil extract to catalytic converters hung around cows’ necks.
But it’s a particularly appealing option for New Zealand, because while feedlot farmers can add inhibitors to grain, that’s tricky for cows and sheep munching on grass. However, as the race to beat Covid showed, vaccines are tough (and expensive) to crack.
How would it work?
Unlike humans, sheep and cattle can digest cellulose in plants. The first of their four stomachs – the rumen – contains an army of micro-organisms that help ferment the feed into a sauerkraut slurry the animal can then turn into energy.
Among the microbes are methanogens, which combine fermentation by-product hydrogen with carbon dioxide, to produce methane and water.
The animal can’t use the methane, so they burp it out. And therein lies 43% of New Zealand’s greenhouse gas emissions.
So a vaccine would need to prevent those methanogens making so much methane, by stopping their growth, cutting their number or reducing their ability to hoover up the hydrogen.
Sounds pretty straightforward, right? “When we started, in 2007, we didn’t even know which methanogens were in the rumen,” says Janssen, who is the project’s lead microbiologist.
“We have to invent every method, because there’s nothing available. You can’t just go and say ‘Oh, we’ll take this off the shelf’. Nearly everything we do, we have to invent, we have to show that it works.”
That’s because no-one else has been doing the work. That could mean two things – that New Zealand is leading the world. Or that we’re deluded.
Australia’s CSIRO research organisation did try – and failed. Their method seemed the most obvious, so the AgResearch team also tried it. And also failed.
That kicked off what Janssen calls a “deep science approach”.
A decade (and millions in funding) later, the team still has not achieved a measurable drop in the burped-out methane of trial sheep. But they’re still hopeful.
“We believe we have the right strategy or approach for being able to develop a vaccine. If it’s possible,” Janssen says.
That strategy involves finding the right antigen to produce antibodies, which spill over from the blood into the saliva. With sheep making 10-16 litres of saliva a day, and cattle slobbering up to 200l a day, that saliva then delivers antibodies to the rumen, where they bind to the methanogens and stop them working properly.
So far, the team has shown that the same methanogens hang out in all ruminant animals, although the mix might change between species.
They’ve identified a clutch of antigens they can use to vaccinate a sheep, take some blood to extract the antibodies produced, and then test those antibodies on methanogens grown in the lab.
And, critically, they’ve shown that those antibodies bind to the methanogens not just in the pristine lab environment, but also in the pea soup of the rumen.
The last step is monitoring vaccinated sheep in climate-controlled boxes to measure whether they produce any less methane than their unvaccinated peers. The target is to reduce methane emissions by 30%. While more might be possible without adverse effects, previous research has shown 30% is safe.
Rather than a single Eureka moment, science can be more like a game of snakes and ladders. Edging past critical waypoints that could send you slithering back to square one.
While they haven’t yet found the ladder to success, they also haven’t encountered a deal breaker snake, says Wedlock, who is the project’s lead immunologist.
“We’ve posed these barrier questions and haven’t come to anything yet that would kill the programme. That gives us optimism, that with our very science-directed approach we will be able to ... find those tricks to make this vaccine work.”
A vaccine by 2035? Really?
The road to scientific breakthroughs is paved with wishful thinking. A 2015 story declared “Outcome of methane vaccine will be known in months”. Nine years on we still don’t have an answer.
While the Climate Change Commission’s advice states “a vaccine could be available for dairy and sheep and beef by 2035”, the fine print notes the estimate is “optimistic”.
That assumes the perfect antigen will be found by next year, leaving 10 years for commercial development and regulatory approval. “At this point there is a low level of confidence that we will discover an appropriate agent by 2025,” the technical report concludes.
Janssen says 2035 is “not unachievable”.
The vaccine programme is supported by the New Zealand Agricultural Greenhouse Gas Research Centre (NZAGGRC) and has received $31 million since 2010, from the Government and industry.
That includes $2.5m in the past two years from new public-private partnership AgriZero NZ.
A 2018 review found the NZAGGRC did good work, and was good value for money, but “there is a need for urgent acceleration in the development and implementation of mitigation options”.
Climate Change Commission chairman Rod Carr says methane-reducing technologies have great potential to cut methane further than farming adaptation can achieve. But their unpredictability means they shouldn’t be the only tool in the box.
“There is still uncertainty around when they will be available to farmers, which poses a risk if we were to rely on them solely to reduce emissions.”
Are we concentrating too much on methane anyway?
Just after the Climate Change Commission released its advice, the Government announced a review of New Zealand’s methane reduction targets.
The country has pledged to lower biogenic methane emissions from 2017 levels by 10% by 2030 and by 24-47% by 2050.
The reason the targets are controversial, other than the obvious commercial risk to one of the country’s biggest earners if stock numbers have to be reduced, is because methane behaves differently to carbon dioxide.
While it’s a more potent heattrapping agent, it’s shorter-lived. Which means if animal numbers are static, you’re maintaining rather than worsening the warming effect.
(New Zealand’s agriculture emissions increased by 13% from 1990-2021, due to big increases in dairy cows and nitrogen fertiliser use. They peaked in 2014, when dairy cow numbers peaked, then stabilised and, in 2021, fell by 1.5%.)
As Canterbury University physics professor, Dave Frame, puts it: “It’s the second-most-important greenhouse gas globally, but it’s a long way behind CO₂.
“CO₂ builds up, so every kilogram that comes out of your tailpipe, about 30% of that is still in the atmosphere 1000 years later. Whereas the methane you consume from rice or ruminants is pretty much gone after about 50 years.”
Frame, a former Climate Change Research Institute director, believes New Zealand should still reduce methane emissions, by at least 10-25% by 2050.
“I think we should definitely do something on methane, because it is a powerful greenhouse gas. But it doesn’t need to go to zero.
“Modest cuts to short-lived pollutants stabilise the contribution from those gases. So globally, to stay under 2 degrees [of warming] will probably need to have methane emissions drop a bit. But the big job will be getting CO₂ emissions all the way to zero.”
But Victoria University adjunct professor, and Climate Change Research Institute founder, Martin Manning says limiting warming below two degrees globally needs methane cuts of 50% or more. “If you even cut out all the fossil fuel emissions, it would not be enough.”
The fact New Zealand’s agriculture emissions have stabilised is not a reason not to cut them, Manning says.
“The point is, you’ve gone too far. You have to back out.”
Manning thinks investing in methane-busting technologies such as a vaccine makes sense. But would that money be better spent trying to cut CO₂?
“You’ve got to find more money. You’ve got to do both.”
Frame also reckons methane vaccine research is “a legitimate thing to look at”. It makes more sense than spending billions trying to cut CO₂ by “buying someone else’s trees instead of reducing emissions at home”, he says.
There are now several groups globally trying to make methane vaccines, using different approaches. Janssen and Wedlock take that as evidence they’re not completely deluded.
Wedlock says it’s a privilege to work on something so important.
“If we can produce a vaccine it will have a worthwhile impact on climate change and the economy, not just for myself but my children and their children.”
But that also comes with a responsibility, which sometimes weighs heavily, Janssen says.
“You think, man, we’d better get moving, and have fewer meetings and do more lab work ... And if it doesn’t work, we want to make sure we can at least walk away going ‘We gave it our very best shot’... And not say ‘Oh well, that was a few years of nice funding’.
“There’s no interest in that for us, because it’s not fun. The fun part is actually making it work.”