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Big decisions still lie ahead as to how New Zealand reports its GHGs to the United Nations. Keeping short and long-life gases separate in the reporting headlines is vital

Big decisions still lie ahead as to how New Zealand reports its GHGs to the United Nations. Keeping short and long-life gases separate in the reporting headlines is vital
Background image: Paul Sutherland Photography
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A key forthcoming decision for New Zealand is how it will report to the United Nations on its Paris Agreement milestones.  On the surface, this many seem something for the bureaucracy to deal with, but the reality is very different. The issue is of fundamental importance.

The big question is whether New Zealand highlights the so-called total carbon dioxide equivalent number (CO2e) or whether it highlights the separate targets and achievements for short and long-lived gases. Once determined, the reporting metrics are locked in.

This question has been raised by the Climate Change Commission (CCC) in its draft report. Unfortunately, the issue has subsequently been largely ignored by the media, by commentators and also by rural industry groups, all of which have failed to recognise its importance in shaping the issues.

The CCC lists many recommendations in multiple categories and asks 24 consultation questions. Recommendation One in the Nationally Determined Contributions (NDCs) category is that New Zealand should report internationally using a combined figure for short and long-lived gases. Question 22 is whether or not this is the best way to do it. I say that it is not.

To understand why this is so important, we need to backtrack about three years. At that time the dominant perspective within Government was that short and long-lived gases could all be bundled together. But then, Simon Upton in his role of Parliamentary Commissioner for the Environment presented arguments why they should be considered separately.

Neither the Greens nor the Labour Party were impressed with those arguments, but Winston Peters picked it up. Hence, separate targets have been listed in the Climate Change Response (Zero Carbon) Amendment Act 2019.

This Act says that New Zealand must reduce net emissions of all greenhouse gases except biogenic methane to zero by 2050. In contrast, biogenic methane has to be reduced by 24-47% below 2017 levels by 2050, including 10 per cent below 2017 levels by 2030.

Those emission reductions for methane are going to be challenging, but not impossible. The target is much more achievable if the 24% minimum figure is the one that is retained.

There are two very good reasons why agriculturally sourced (biogenic) methane needs to retain its strong separate focus. The first reason is very specific within Article 2 of the Paris Agreement.

Article 2 says that countries should “adapt to the adverse impacts of climate change and foster climate resilience and low greenhouse gas emissions development, in a manner that does not threaten food production”.

This statement is not hard to find. Article 1 of the Agreement is simply definitions. The statement about food production in Article 2 is in the first substantive paragraph of the Agreement.

So, let me say it very clearly: the Paris Agreement is not meant to threaten food production. Linked to this is something else I have said many times before: most of New Zealand’s pastoral soils and topography are not suited to crops.

Despite the prominence of the Paris Agreement statement about not threatening food production, it is almost never referred to either by mainstream New Zealand media, nor emphasised by rural industry groups.  Instead, the agricultural industries have allowed themselves to be side-tracked into fights that they can never win.

Too often we read about rural groups arguing that agriculturally-sourced methane is unimportant in relation to global warming. Yes, it is correct that the agriculturally-sourced methane in New Zealand is produced from carbon dioxide that is drawn from the atmosphere by photosynthesis, and this eventually ends up back in the atmosphere as carbon dioxide. However, in the meantime while it is in the form of methane for approximately 12 years on average, it does contribute to global warming.  Based on the science, we can never win an argument to the contrary.

People also get unduly distracted by issues of soil carbon. Yes, the carbon that is contained in the soil is very important, as is the carbon contained in the world’s rain forests. But greenhouse gas policies are measured by new sequestration and not by stores of carbon.  If agriculture wants to get credit for soil carbon, it will have to be new carbon that is sequestered net of any carbon that is being lost, for example by draining peat soils and by cultivation on all soils. Agricultural interests might win a few battles but they won’t win the war this way.

The second area that agriculture should be focusing on is the impact of bundling the methane into units of carbon-dioxide equivalence. This started almost by accident way back in the 1990s using the 100-year warming estimate of a tonne of carbon dioxide as the baseline. Most countries did not care greatly about the use of carbon dioxide equivalence for methane, given that for most countries biogenic methane is a minor component of total emissions. But for New Zealand and some other small agricultural exporting countries like Uruguay, it is a choice that totally screws the scrum.  If, for example, the effects of methane and carbon dioxide are compared based on 200-year effects then we would get a greatly reduced proportion of CO2e coming from methane.

The key issue with CO2e measures for methane is that it is like comparing apples and onions. There is no sensible way of bundling up the onions into apple equivalents. It could be on the basis of sugar, carbohydrate, fibre or even some unit of smell. Take your pick and get your answer!

Way back in 2006, I took up the issue of flaws in the CO2e concept when applied to methane. The article was published in the Journal of Primary Industry Management. Almost certainly, I was the first person to take up this issue in New Zealand. But no-one seemed particularly interested and at the time I had other fish to fry. I did not persist with the issue.

The key message in all of this is that the rural sector of New Zealand needs to fight to keep methane issues separate from carbon dioxide. Once they are bundled up into unts of CO2e, there is no way that methane will receive the separate consideration that it needs. That includes the way that we report these issues to the United Nations, which will flow straight back into New Zealand reporting.

In contrast, the CCC report (p163) advocates bundling everything into one headline number. It suggests that there might be other ways of highlighting the special issues of methane but gives zero indication of how that might occur. I see that as a big cop-out. And it locks in that headline number as a mandatory requirement.

One of the problems for the rural sector has been insufficient expertise on greenhouse gas issues within industry bodies such as Federated Farmers. I have yet to find any professional staff in that organisation who can engage with the issues at the necessary level of depth. The industry has been fortunate that people like Parliamentary Commissioner Upton have rolled up their sleeves and generated useful debate from a position of insight. But that does not replace the needs for groups such as Federated Farmers to have their own professional specialists who can engage with these issues from a similarly informed position.

*Keith Woodford was Professor of Farm Management and Agribusiness at Lincoln University for 15 years through to 2015. He is now Principal Consultant at AgriFood Systems Ltd. His articles are archived at You can contact him directly here.

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Keith, did you see this new research that suggests that soil may not be as good a carbon sink as we thought?
It's a bit worrying if that's the case because getting carbon in to soil was basically the best opportunity we have for getting it out of the atmosphere

False economies
I had not seen this. But it reinforces the point that carbon cycles are very complex.
Several years ago at a conference I had dinner with a scientist who has spent most of his professional life studying soil carbon. After several hours I summed up our conversation by saying to him that really we understand very little about what is going on in the soil in different situations. He could not argue with that.
The biggest long term sink for CO2 and also heat is that nature by itself shifts both CO2 and heat down into the deep oceans until a new equilibrium is reached. Fortunately, the specific heat of water is much more than that of air. Also, there is a lot of water to absorb the CO2. If it were not for nature doing these things then we would be in a lot more trouble.

For anyone interested, this is what Keith is talking about in terms of numbers
It's from a few years ago but basically we are (were) emitting 6 giga tonnes (now more like 10 giga tonnes) and the oceans take up about 2 of that (which is useful but not great long term with warmer oceans/acidification etc) and everything else was pretty much balanced.
Soil is certainly complex stuff that we totally take for granted...
Here's the original Nature article

Yes, this is a very nice diagram (which I had not seen before).
It captures very nicely the relative scale of stocks and flows.

Indeed. I think it shows very nicely how we are "tipping the balance"

One of the relevant issues is whether or not the net ocean sinks are increasing as the atmospheric stocks increase. The numbers I have seen indicate that about one third of the CO2 emissions are still disappearing into the deep oceans each year. The departures are driven by the difference in CO2 concentration between atmosphere and ocean and the CO2 gradient within the ocean, and these are increasing. So although emissions have increased since this diagram was constructed about 13 years ago, so have the consequent sinks into the deep oceans. But everything is complex and all of the numbers are soft. Part of my criticism of our rural industries is that they have not geared up with people who can engage in the debates. The idea that 'the science is settled' does not align with what is really known. There is a lot still to be learned.

FE The science you quote said " SOC stocks increase with eCO2 in grasslands ± 2 per cent) but not in forests (0 ± 2 per cent)" Which reinforces the soil carbon pamphlet produced by Pggrc,

This is yet another very good document on the relevant science of soil carbon, what we know and what we don't know!

Excellent brief thanks Keith. The complexity of the GHG issues is daunting to all but the super bright and even more so for farmers who are fighting against all of the other complex issues theyve had to deal with down on the farm!

Ive found this "book" to be pretty accurate in regards to what we as humans have done to the world over the last 200 years (unintended consequences) and a pretty detailed view of what we need to do to get control. Seems clear that we will never be able to line up all countries to be on the same course at the same time, so essentially we are all "sh#*ting in our own nest"!

I have downloaded the book - as you will have previously found out it is free - and had a quick look.
My initial thoughts are that it is very good.
Hopefully some others will download it.

Thanks for the link Grumpy.
PDK might like it....

Haha - he probably put me onto it...........

Guilty as charged.


Good, isn't it?

Not sure "good" is the word I'd use. Scary? Depressing?

It's so smart how they took a real world issue like pollution, biodiversity loss and environmental degradation and twisted and simplified it into a financialized market of select gas emissions. Bravo!

Yes, largely thanks to the Kyoto Protocol I think. It is worth noting the success of the Montreal Protocol policy initiative in comparison - the latter UN agreement being a regulatory, as opposed to polluter-pays, mechanism to combat a similar (i.e., atmospheric) environmental issue;

Hi Keith
can you explain to me why we ignore the fact that New Zealand when it signed up to the Paris agreement also signed up to 4p1000.
The study by L Shipper attached to the BERG report stated that on average over 30 years NZ pastoral farming achieved increasing carbon in soil of 0.6 tonne Carbon/Ha/annum, so we are there.
Yet the Climate Change Commission ignore this and their only solutions GM ryegrass (gives the Pggrc and or NGARC a future income in perpetuity). I see this as a conflict of interest. Have I missed something?

I will have to do some more reading.
But the '4 per 1000' initiative is for an increase of 0.4 % per annum.
You refer to 0.3 g/ha per annum in the BERG report. Is that what you meant? If so, it is a trivial amount relative to the 0.4% per annum.

thanks so much for replying, it would depend on your initial total levels, and its where comparing % is problematic, apologies for doing so, but its their name. Re reading the report "pasture soils on stable mid-slopes pof hill country gain .6 tonnes C/ha/annum." Pasture is the only land use that is increasing carbon, forestry, horticulture and cropping all lose soil carbon as the Pggrc admits, when you look at what the CO2 equivalent of a T of soil carbon it is massive. This legislation is potentially draconian if FARM are right, we have to destock and pay an ever increasing tax on the livestock we market. There is no end point. I am sorry but I feel so threatened by this, we are likely to loose our home and livelihood. They want an ever increasing amount of land for planting to "offset" industries emissions and they have eyed sheep and beef land as the least economic loss. That ignores the fact it brings in foreign exchange. the GM solution they offer is simply lower protein grass, well just graze the grass at a later stage. Europe does not want GM, China does not want it, our markets do not want it. It is not a solution
We have submitted asking for the split gas approach as you've highlighted.
Also consider we are talking about the living carbon cycle. We want to credit photosynthesis and tax respiration. Methane is a component of all living ecosystems. Nowhere more so than tropical rain forests. West coast will be right up there. If you really want to live in a low emissions environment may we suggest a desert, (still some), or the moon (zero emissions) Far more manageable are ecosystem processes of solar,water and mineral cycles along with community dynamics (diversity). If these are all thriving whatever the landscape, we will always have a hospitable environment. Life begets life and the more of it the healthier we will all be. I'll edit my mistake above, my .3g should read .6 tonnes.

... I am very confused ... back in the day when I went to school , when dinosaurs still roamed & laid their eggs in primeval sand tracts ..... CO2 was a good thing : plants sucked it up .... couldn't get enough of it .... transformed it into leaf growth , fruits , avocados on toast .... yummy .... Now , in 2021 , the UN are demanding we stop CO2 production .... damnnnnnn ... I love smashed avo on toast , with T.rex eggs poached , and a smidgen of hollandaise sauce .... Sigh !

:) And a couple of litres of water a day is good for you but 100 litres would kill you....
More CO2 doesn't necessarily mean higher yields of everything. It's a bit more complex than that

Thanks Keith. How we phrase and justify our Nationally Determined Contribution is important but perhaps the most important thing is the target reductions for each gas and how we go about achieving them. After all, the split gas target is already written into the Zero Carbon Act and I don't hear anyone seriously challenging it within New Zealand. We are sure to face some opposition internationally though, as our 2050 target is weaker than what some others are doing, namely full net zero.

For biogenic methane the CCC's draft advice put biogenic methane reductions at the lowest level of what the world needs to achieve on average. But later, in the NDC section, they say our fair share would be "not less" than the world average. They don't discuss the significance of current biogenic methane being 10 times the world average per capita to start with, and whether that is a fair starting point for calculating reductions. I'm also finding their suggestions for how to achieve their pathway a bit vague - is it all going to be voluntary?

One advantage of the split gas target is that if reducing biogenic methane does turn out to be easy, say through a feed supplement, then that doesn't let us off the hook on fossil fuels.

I'm looking forward to reading your submission to the CCC when it is available.

The CCC is arguing for our national targets being headlined to the world based on CO2e rather than as the split targets. And it is the headlines that count.
I would not expect to influence the CCC at this stage and I have not written a formal submission to the CCC. The key issue will now be what the Government decides to do with the specific recommendations. From feedback, I know my articles do get circulated in Wgtn so hopefully some relevant people will read what I have said.

The Commission argues in Chapter One of its evidence report that the difference between GWP100
and GWP* isn’t important because; ‘the split-gas 2050 target already reflects the different warming
effects of biogenic methane’. But in the advice document, the Commission suggests that for our
international standing it would be best to take a single all-gases approach to our NDC, in which case
the Commission should be using the GWP* metric.
When it comes to our NDC accounting, the Commission is happy to look at long-term effects of a
forest on carbon stocks. Averaging smooths out the ‘peaks and troughs’ associated with forestry
fluctuations (How to measure progress, 17). But in its argument against GWP*, it shows that it is not
willing to extend the same logic to biogenic methane.
Grandparenting shouldn’t be the off-putting fear of GWP*. To use Dr Michelle Cain’s analogy of the
metric - a power station emits CO2 by burning fossil fuels, when it shuts down it emits no more and is
not taxed, despite the fact that CO2 continues to affect climate for hundreds of years. Meanwhile
with a herd of cows, if it maintains the same size, it does not contribute to warming (Cain, 2018). A
herd of 100 cows isn’t contributing anymore to warming than a herd of one cow, so long as New
Zealand’s herd as a whole isn’t significantly increasing in size. Neither the herd of cows, nor the
defunct power station are contributing to warming, yet the Commission using the GWP100 metric
seeks to tax and punish the farmer for their herd’s emissions every year, and has evaluated the
GWP*’s value based on how well it can punish farmers too.
One reason the Commission gave for not using GWP* is that farmers don’t make their decisions in
perpetuity, that stock levels can fluctuate with climactic events such as drought (much in the same
way forestry levels can fluctuate) - to which I say, if the Commission is incapable of factoring in
climatic events in their climate change policy modelling, I have some deep concerns about the validity

The problem with the GWP* concept is that it has gained almost zero traction internationally and it is not easy to understand. It is also based on its own set of assumptions as to how we turn onions into apple equivalents. If we were to try and use it as our metric for GHG measurement we would first have to educate the world. I think that would be very challenging.

GWP* was featured in the Intergovernmental Panel on Climate Change (IPCC) special report on ‘Global Warming of 1.5 °C’, and it will be assessed as part of their 6th Assessment Report - which isn't due until early next year, so it is too early to tell what the IPCC will decide which is perhaps why the metric hasn't gained traction. Not a marker of its quality, but of the slow nature of consultation and debate.

Professor Myles Allen, an author on previous assessment reports, has said: “Basing climate policies and emissions trading systems on a metric that doesn’t demonstrate the impact of different pollutants on global temperature presents a serious risk to the reputation of environmental policy, and risks undermining public confidence. A switch to GWP* would not only prevent this but would also be relatively easy, as it uses information that is already reported in the UNFCCC system.”

Additionally, other countries do not have the same problem as New Zealand with methane which likely plays a role in the traction of GWP*. As you pointed out, other countries haven't been concerned about how methane is measured, they have no reason to change. We have a unique emissions profile, which demands that we, more than other developed countries, use the right metric that demonstrates the impact of methane as a short-lived gas, a better comparison of onions to apples to equivalents that actually reflects its behaviour. The split-gas approach has barely gained the rural sector anything, considering it has been split out and still looked at in terms of CO2e. It still allows the reduction of methane to offset the lack of reductions of carbon dioxide from other sectors, and this still poses a threat to the rural sector.

Also I'm sorry but in reference to another of your comments that you see no value in making a formal submission process - what better time is there to contribute your opinion than when they're asking for it?

It is great to see these comments from someone who is actually reading the literature!
I think the next ten years are going to be very interesting as the general public starts to understand the implications of what we are signing up to.
There are still going to be lots of debates ahead of us and at this stage my focus is on trying to ensure that the framework of that debate allows the ongoing debate to be informed. but from here on in it is gong to be very hard to change the metrics of reporting.
For me, allocating time to various issues is always a challenge and my assessment is that a formal submission, constrained by the word limit imposed by the CCC relating to this particular issue of 400 words, would have got lost in among all the other submissions. So instead I chose to say something in public, here and at Farmers Weekly, where in combination a lot more people would read it. In the final analysis it will be the Govt and not the CCC that makes the decisions.

Maltwix - some of both commented, and pointed out that the scoping was hopelessly narrow.

Whether Carr's epithany went the full way, I very much doubt. And the Govt won't want to let the cat out of the bag - aided and abetted by the MSM (see latest listener for a classic example of such hustling - the Editorial is a shocker, totally a fail, journalistically - and there's a spin-piece to boot). If it even knows there a cat. Or a bag...

This is a Limits to Growth issue now; linked to overpopulation, over-specialising, over-reduction of capacity/resilience, failure to understand energy and entropy. Whether the CCC exercise is worth doing, I doubt. Twenty years ago, it might have had time to educate the public. Now, the public are still being urged to consume, but somehow to do so without emitting carbon. At least we've worked out how to grow virtually; that has to end well.....

Keith - biogenic methane while it retains its original form may contribute to global warming, but if the volume of methane emitted by NZ's livestock is consistent ie if the volume being emitted equals the volume degrading to CO2, as would be the case with stable stock numbers, would it contribute to an increase in global warming? The focus is on attempting to keep the rate of increase below 2 C, and 1.5 C if possible.

The latest argument is that some of the residual heart remains after the gas itself has gone. This applies to al gases, not just methane. The details thereof are definitely not settled science.
Keith W

The level of insight in the general community as to the implications of new nuclear technologies, including but not only molten salt reactors and thorium, is currently very low. My own assessment is that the impact will be profound but timelines remain difficult to judge.

EROEI, Keith. How much energy required to sieve that there thorium?

Getting uranium from seawater is about the same cost as mining. So don't go wringing your hands about peak uranium. "In addition, the technique can even use waste fibers for a greater cost savings and that analysis shows that seawater extraction could be competitive with land mining at present prices."

“…nuclear power’s price is dominated by the cost of power-station construction and decommissioning, not by the cost of the fuel. Even a price of $300/kg would increase the cost of nuclear energy by only about 0.3 p per kWh. The expense of uranium extraction could be reduced by combining it with another use of seawater – for example, power-station cooling.”

New Zealand needs to pull the pin on any commitments to this, the whole thing is total guesswork. Continue down this track and back yourself into a corner and it will bring the whole country down by having to end up paying a truck load of money in the form of yet another tax to someone else thats doing nothing with it to solve the problem. Wake up guys. I recommend the Politicians keep on waffling on about this and kick the can down the road. Major polluters around the world need to sort their own mess out, not drag us into it.

Sorry, but WE are the major polluters.

If we didn't buy their crap, they wouldn't exist.

"I have yet to find any professional staff in that organisation who can engage with the issues at the necessary level of depth." Who in government has the depth? "The climate system is a coupled non-linear chaotic system, and therefore the long-term prediction of future climate states is not possible. "

Exactly, as I understand it - this is why the IPCC does projections, not predictions.

And what I've found is that few regulators understand the difference.

So we should have the humility to accept we can't predict future climate states and focus our resources on solvable problems like sanitation, healthcare, vaccination, malaria, clean water, pollution, education... rather than virtue signalling about the climate in 2100.

It has been proven by many studies as well as the disappearance of C14 after the French nuclear tests that CO2 molecules only last in the atmosphere less than 15 years before being absorbed into the oceans or biosphere. The mantra that anthropogenic CO2 lasts hundreds of years in the atmosphere and is the cause of the increase from 280 to over 400ppm over the last 170 years can only be argued with the use of creative science concepts such as perturbation time and adjustment time. In fact CO2 is a short lived gas in the atmosphere at a molecular level and this makes a nonsense of the GWP100 metric.

You are well named.

The oceanic capacity to absorb, is of course limited. It is a 'sink', and as such has capacitive limits, well before which some shellfish have problems living up to their name.

"Or biosphere?" Bollocks. We evolved on a planet with that carbon locked away underground. We are digging it up, burning it, and altering the biosphere. Classic spin - who pays you?

So what's your explanation for the increase in atmospheric CO2?
It really isn't that hard to understand

The rapid removal of C14 from the atmosphere subsequent to nuclear tests is a known fact. And is is very remarkable! So to that extent your argument is correct. But the implications of that for the overall carbon cycle and atmospheric residence time of CO2 are somewhat complex. Because of the complex interplay of CO2 transfer between the ocean and the atmosphere, the fate of individual molecules does not tell us directly the atmospheric residence time of an increased concentration of CO2. There is considerable uncertainty as to the correct atmospheric residence time of CO2 and it may well be much shorter than commonly believed. But it will still be considerably greater than indicated by the removal from the atmosphere of C14.

Agree that this is a major aspect of our emissions strategy and obligations. Also agree that we are hugely impacted by methane from agriculture contributing nearly 50% of our overall GHG when compared to the USA and UK where they area round the 8% levels. Numerous governments have bent over backwards to minimise any costs applied to agriculture. ETS is but one example, and separating out farm emissions yet another. If you use the “food production” get out of gaol free card then the complete horticulture industry can make claims to have their emissions excluded as well! It's simply time to accept that we need to reduce the demand for meat and dairy products over the next three decades. There is simply no way we can meet our obligations whilst still protecting this one industry... even the Climate Change Commissions's draft report cannot find any way of getting to net zero by 2050.

But who will feed the 50 million soles that we (NZ) feed now..................

There are no easy answers! This problem requires the whole world to work together and comply in harmony - this I feel is the real issue! On balance the science is clear and supported by sound evidence.

Mangawhai Steve,
Your argument builds from a starting point that agriculture contributes 50% of our overall GHG but does not acknowledge that this '50%' figure is a direct consequence of the choice of GWP100. Another parameter of the system is that the methane is allocated to the farmers rather than the food consumers. So a small country of 5 million caries the CO2e burden of feeding 50 million people who carry zero CO2e burden for their food choices. Our own demand for meat and dairy has very low impact on our NZ emissions because we are an exporting country with around 95% of these products exported.