The conversation about climate ambition from our farming sector is one of fairness, achievability and economics, not of science
Analysis: By the end of 2025, the new National-led government will be required to make a critical decision on whether to keep or change New Zealand's climate targets.
Those targets include the net zero by 2050 pledge for long-lived greenhouse gases like carbon dioxide and nitrous oxide, plus a commitment to reduce emissions of methane by 10 percent from 2017 levels by 2030 and by 24 to 47 percent from the same baseline by 2050.
While the net zero target is unlikely to change significantly, farming groups have long been dissatisfied with the ambition of the methane targets and National in its agriculture policies suggested it might change the targets in line with the sector's preferences. Environmentalists, on the other hand, have pushed for methane reductions to go further.
READ MORE: * National plan could halve NZ's ambition on methane * Farming's big warming impact needs a fair price
With agriculture making up nearly half of New Zealand's emissions on a carbon equivalency basis and being responsible for 70 percent of the country's contribution to global warming, the methane targets were always going to be contentious.
To try to take the political heat out of the debate, the Climate Change Commission has been tasked with recommending any changes to the 2030 and 2050 targets. Its advice is due by the end of next year and the Government will have 12 months to formulate a response. A change should only be recommended if there has been a significant change in circumstances, including new scientific understandings of climate change, according to the Zero Carbon Act.
That process has had an early start, with the commission seeking submissions between April and July of this year before it releases its draft advice.
Farming groups Dairy NZ, Beef + Lamb and Federated Farmers entered a joint submission, appending research they had commissioned from leading climate scientists about the warming impact of New Zealand's current climate targets. That research found New Zealand's contribution to warming would peak in the 2030s and by 2050 return to 2022 to 2027 levels, depending on which end of the methane range was met.
"We believe this report provides additional context that is relevant to New Zealand. It demonstrates a significant development in the scientific understanding of what is required for New Zealand to achieve no further warming from biogenic methane since the commencement of Section 5T of the Climate Change Response Act in 2019," the groups wrote in their submission.
In a surprising move, the Parliamentary Commissioner for the Environment Simon Upton has now pushed back, releasing a letter to the three groups and the Climate Change Commission which disputes the research being new.
"This study appears to be more or less a repeat of the modelling exercise I commissioned and summarised in my 2018 note on New Zealand’s methane emissions from livestock," he wrote.
While there are slight methodological changes between the study, they produced very similar results of what level of methane reductions would be consistent with contributing to no additional warming from agriculture beyond what has already occurred.
DairyNZ and Beef + Lamb told RNZ the main point of the report was to understand the warming impact of the current targets, not determine what targets would halt agriculture's contribution to warming. This is a new exercise, it's true, but not based on any new scientific understanding of climate change.
In reality, the science of the warming impacts of methane and carbon dioxide and other major greenhouse gases is well-understood and has been for decades. While there are continual advancements, there have been no groundbreaking findings about the physical traits of these gases and their effect on the climate since the original methane targets were set.
What level of ambition we should aspire to on methane is a political call, incorporating questions of fairness, achievability and economics. There is no lingering scientific question whose answer will produce a perfect methane target.
By pretending it's an issue of science, the sector is seeking to obfuscate the necessary conversation about what level of global heating is acceptable from New Zealand's agricultural activities.
The broad shape of the science is settled. Here's what it says.
When carbon dioxide enters the atmosphere, it stays there for hundreds or thousands of years. Some CO2 is removed by oceans and vegetation as part of the natural carbon cycle, but this is (roughly) offset by natural CO2 emitted from these same sources. Human activity, through additional tree planting or through chemical processes yet to be deployed at scale, can also sequester carbon dioxide.
As long as CO2 isn't sequestered by humans, it will continue to warm the world. Constant emissions of CO2 mean the world will keep warming at a constant rate. As emissions fall, the rate of warming will fall. If they hit net zero (emissions fully balanced by sequestration), warming stops completely. If we begin to sequester more than we're emitting, the world will start getting less warm – ie, it will cool.
Methane is very different. It lasts in the atmosphere for only a matter of decades and leaves behind just a trace of CO2. While it's up there, it has a significant heating effect, but that is time-limited. If methane emissions grow, warming increases rapidly. If they decline very slightly (around 0.3 percent per year, according to the Intergovernmental Panel on Climate Change), warming stops. If they fall further, warming plummets – ie, the world cools rapidly.
This is where the concept of "no additional warming" comes from. Under the Climate Change Commission's ambitious demonstration pathway, CO2 doesn't hit net zero in New Zealand until the late 2030s. In the meantime, the carbon economy (basically every sector other than agriculture and waste) is adding to warming.
New Zealand's methane targets, meanwhile, are more ambitious than that 0.3 percent per year, so the methane economy is expecting to reduce its contribution to warming while the carbon economy is still heating the world.
That perceived unfairness has driven recent efforts by farming groups and the National Party to rework methane targets to be consistent with no additional warming.
Such targets, based on the 0.3 percent figure, would more than halve our ambition on methane. Upton's 2018 research found slightly steeper cuts would be needed, on the order of 10 to 22 percent below 2016 levels by 2050. The new report commissioned by the farming groups put the figure at 15 to 27 percent below 2020 levels by 2050. Still, the current targets are much more ambitious than this.
While National did promise to review the targets in line with "no additional warming", its climate spokesperson Simon Watts suggested to Newsroom that the party wouldn't weaken the current targets.
"Our status quo is that we are committed to meeting our current targets around methane. That's the starting point," he said prior to the election.
"On the basis that we accept the current status quo, it doesn't infer that we are going to default to a softening position. Absolutely not. Our view is we need to accelerate our ability to meet our targets."
In an interview with Newsroom, Upton said neither report answered the key question of whether "no additional warming" is in fact a desirable target.
"That's not a thing I can have a view on. It's a policy question. Politicians have to make this decision," he said. "But, if you're going to say our position is that we won't add to warming, we'll keep it where it is, fine. Then you need to say, we're going to continue to cause warming at a stable level. The logic of that is, you are claiming a right to warm the world to that extent, which is a perfectly legitimate policy position, but you need to be clear that's what you're doing."
In other words, a "no additional warming" approach locks in all of the warming caused by New Zealand agricultural methane to this point. That's about 60 percent of all of the warming New Zealand has caused since 1850, according to the figures underlying a different report released by Upton last year.
This is where the questions of fairness, achievability and economic considerations come into play.
Fairness exists between and among sectors, to start with. Agriculture is being asked to cool the climate while other sectors still contribute to warming, but taking the long view, it will still be responsible for 63 percent of New Zealand's contribution to global warming by 2050. The carbon economy, meanwhile, is being asked to make much more significant changes to reach net zero emissions while agriculture argues over a quarter or a halving of emissions by 2050.
There's also New Zealand's international position to consider here. Under the Paris Agreement, we've committed to targets that are as ambitious as possible while still being achievable. The UN climate framework also recognises that developed countries like New Zealand have different responsibilities than developing countries, given our long history of emitting.
If we were to lock in our current methane warming – which represents around 0.15 percent of the global warming to date, even though our population is just 0.06 percent of the global population – we would have to justify that to our international peers.
Of course, achievability of a target is also crucial. The government will need to ensure that whatever level of ambition is selected, we can meet it. But targets should be something we have to stretch for, to show we truly are being as ambitious as we can.
These are complicated questions and there aren't easy answers to them. But they are a necessary part of the coming debate over our level of methane ambition. These are discussions that need to be had, not papered over by pretending it's all about the science.
