The Climate Change Commission proved its independence on Sunday when it broke a political taboo in proposing one way to reduce methane emissions from the agricultural sector: Have fewer cows.
While the Commission estimated current policy settings would already lead to an eight to 10 percent reduction in the size of the national cow – and sheep – herds by 2030, it said something on the order of 15 percent would be crucial for meeting emissions reduction targets.
At issue is the thorny problem of biogenic methane, which is produced by decomposing organic matter (the waste sector is responsible for 10 percent of biogenic methane emissions) and the natural digestive processes of ruminant animals, including cows, sheep and goats (the other 90 percent). Methane doesn’t need to reduce to net zero because the majority of its impact on the atmosphere occurs over a much shorter period of time than that of carbon dioxide, which can last hundreds or even thousands of years.
However, there also aren’t too many solutions to achieve even the modest reductions that the Zero Carbon Act calls for – 10 percent below 2017 levels by 2030 and 24 to 47 percent below those same levels by 2050. So long as we keep consuming dairy and meat, our dairy and meat livestock will continue to have to be fed, leading to more methane emissions. Unlike cars, there are no electric cows.
So the Climate Commission came to the same conclusion as legions of experts before them: There are ways to tinker around the edges of how much animals are fed and what they eat, but without the development of new technology like a methane vaccine, to significantly reduce methane emissions you have to significantly reduce the number of ruminants.
Stocking rates
The Commission’s main advice doesn’t discuss too many policies for achieving that reduction, but the supplementary Evidence Report offers a few hints at their thinking. Much of the reduction could come from changes to stocking rate – effectively, the number of animals per hectare. The Commission reviewed research which indicated that the ideal stocking rate is not simply as many cows as you can fit onto the land. Instead, there’s an optimal stocking rate (which changes from farm to farm depending on a wide variety of factors) where productivity is highest.
“Adjusting stocking rates can help to optimise herd productivity and reduce emissions. A herd with fewer cows that maintains the same production (through higher production per cow) would require less feed overall,” the Commission found.
“Careful balancing of stocking rates, pasture and fertiliser management and supplementary feed can lead to a farm system where production, profit and emissions are optimised.”
In the Commission’s projections, while sheep and beef and dairy animal numbers fall 15 percent by 2030, the total volume of milk produced remains flat and the total volume of meat produced increases slightly.
“We’ve been on this path for some time now, around land use change, which is a combination of reforesting a lot of land that’s marginal from an animal production perspective and also putting in place lower intensity farm systems that have better economic and environmental outcomes,” Steve Carden, the CEO of Landcorp, New Zealand’s largest farming business, told Newsroom.
“For example, we’ve built the largest set of organic farms across the country. They are farm systems that require much lower stocking densities but you get paid a significant premium for the organic milk and you get much better environmental outcomes and a lower carbon footprint and the like. There are models for doing it.”
However, others in the primary sector aren’t so keen.
Federated Farmers President Andrew Hoggard said some changes to stocking rates were possible, but that it was more important to meet scientifically-significant methane reduction targets by whatever means possible than focusing on reaching a certain herd reduction benchmark.
“There’s no point milking extra animals if they’re not generating you extra profit. People chuck out [targets] for this year and that year, sometimes I think you just got to look at the steps you’ve got to take first and see where you get to from there,” he said.
“If we end up in New Zealand having to make deeper cuts to our production systems, it’s not sensible from a global point of view. The world needs food, New Zealand can produce food for a lower [per unit carbon] footprint than most other countries.”
New technologies
Dairy NZ chief executive Tim Mackle told Newsroom that the targets should be met primarily through new technologies, like as-yet-unproven selective breeding for low emissions cattle or a methane vaccine.
“We totally support the fact that there will be land use change over time, just as there always has been. There will be that conversion, but to go further, we would say nah, let’s find new technology,” he said.
“The absolutely best types of technology so we can have our cake and eat it.”
But the Commission designed its emissions budgets to be met only with existing technology. In the event of new technologies emerging, that would allow the sector to achieve greater, faster cuts to methane emissions, not offset the need to reduce herd size and implement the other recommended farm management techniques.
“It is likely these technologies will become available, and this would increase the speed and efficiency of reducing methane emissions,” the Commission wrote.
Commission chair Rod Carr echoed that idea when he spoke to Newsroom on Sunday.
“We’ve got 30 years ahead of us, so if we could get ahead of the curve in the early years, that would set it up to manage the risk if things don’t turn out the way we hope in the latter years,” he said.
“Past 2035, we believe to achieve our biogenic methane responsibilities, we are going to need new technologies. We are now modelling a 13 percent reduction of biogenic methane by 2030, a 20 percent reduction by 2035, but then you get to 24 percent reduction by 2050. In other words, you’ve got very diminishing returns by adapting the change in land use, the breeding and the feeding, you kind of get to the point where you’ve got as much as you can from those, which is why you’ve got those fading additional gains out there.
“So our conclusion is to hit the higher, more ambitious targets, the 47 percent of the range and the 49 to 60 percent reduction in the second half of the century, we are going to need new technologies. And whether that’s in how we feed the animals or how the animals process the food that they eat, that’s a technology that doesn’t exist and is not proven to scale commercially yet.”
In other words, the Commission expects the primary sector to fully exhaust the possible gains from new farm management techniques – including reducing herd sizes – in addition to taking advantage of any new technological innovations.
“It will be a combination of both [farm system changes and new tech],” Carden said.
“It could well be that, with advances in technology plus land use changes which make sense to do anyway even if you didn’t have those particular targets being set, you might end up getting more than 15 percent net effective change over time anyway.”
