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Keith Woodford explains how the narrative is changing in regard to the need for methane emissions, with less need for drastic reductions

Keith Woodford explains how the narrative is changing in regard to the need for methane emissions, with less need for drastic reductions

By Keith Woodford*

The recent note on methane emissions put out by Parliamentary Commissioner Simon Upton in late August, and underpinned by a contracted research report written by Dr Andy Reisinger from the Government-funded New Zealand Agricultural Greenhouse Gas Research Centre (NZAGRC), will change the methane narrative. History will look back at Upton’s note as a fundamental contribution that moved the methane debate towards a logic-based science-informed position.    

The key message is that short-lived gases such as methane do need to be considered differently than long-lived gases. That does not mean that they are unimportant. But lumping them together with long-lived carbon dioxide and nitrous oxide has led down false pathways. 

Some of us have known for a long time that short and long-lived gases needed to be considered separately, and that the so-called CO2 equivalence notion was not helpful. As I have said previously, methane and CO2 belong in different regulatory baskets. But it needed someone from an authoritative position to take a stand.

Upton has made earlier public forays into the topic of short-lived versus long-lived gases, but he was somewhat tentative in putting those views forward. The recent change is that he is now being authoritative, drawing on the Reisinger Report, in saying these issues need to inform the political debate. The Productivity Commission report of early September 2018 has also now picked up on this, that a single cap for combined greenhouse gases is not appropriate.

Dr Reisinger is advising that methane emissions from New Zealand’s pastoral agriculture have already peaked. However, it seems that the quantities in the atmosphere may not have yet peaked – although they cannot be too far away.

Surprisingly, Reisinger does not estimate when pastoral-sourced methane stocks will start to decline, but he does put forward a notion that will be new to many people, that even after the methane has gone it will still have a warming effect due to changes it has created in ozone levels and stratospheric water vapour.

These indirect effects are more than a little contentious and quantification is still at an early stage. However, by bringing in these indirect effects, Reisinger thinks we will have to reduce methane emissions further to prevent further warming.

By including the indirect effects, Reisinger’s calculations suggest that if we are to have no further warming from pastoral-sourced methane, then we need to reduce our pastoral methane emissions by between 10 and 22 percent on a sliding scale through to 2050. On average that is around 0.5 percent per annum, but with a slightly faster rate in early years.

So, how easy would it be for New Zealand to reduce its pastoral methane by between 10 and 22 percent?

Whereas the dominant narrative has been that there is no magic bullet to reduce the required methane emissions from livestock except by reducing livestock numbers, that narrative has been promoted within a political framework where huge reductions in methane emissions were going to be required.

In contrast, reducing methane emissions by Reisinger’s upper limit of 22 percent does not seem particularly daunting over the more than 30-year time period.

Independent of the methane debate, the Government has determined that New Zealand is going to plant large areas of forestry to soak up atmospheric carbon dioxide. This could mean anything from one to three million hectares of new forest.

The pastoral land that will be lost to forestry will be on the hills, with lower productivity than on the softer country. But it is easy to see, with pastoral agriculture currently being in the order of 12 million hectares, that this will be enough to significantly reduce methane emissions, probably in excess of 10 percent, and maybe considerably more.

It is also reasonable to expect methane emissions to further reduce with increasing animal productivity. This has been the way that we have reduced emission intensity from agriculture in recent years.  Put simply, the more productive that animals are, then the less energy has to go into the methane-producing furnace (the rumen) per unit of output.

It’s not easy to achieve increasing productivity from each animal, but consider the increased productivity per animal that we have achieved over the last 20 years with both dairy (more milk per cow) and sheep meat production (higher lambing percentage and heavier lambs). Another 0.5 percent improvement per annum over the next 30 years and we will be well ahead of any zero-warming targets.

It is also insightful to look at the effect of New Zealand’s pastoral-sourced methane on global climate. By Reisinger’s calculations, New Zealand’s pastoral-sourced methane has so far led to global temperatures rising by 0.0013 degrees C above background levels. If methane emissions stabilise where they are now, it would supposedly raise global temperatures by another 0.0002 degrees by 2050.

Those minute numbers help put things in perspective. However, the mantra is that everyone in the world is supposed to do their bit for the greater good, and that includes us.

The contrasting situation of carbon dioxide is that atmospheric levels will inevitably continue building up because it is so long-lived. We would have to reduce carbon dioxide emissions to almost zero to stop those levels building up. So yes, to the extent that climate change is considered a problem, the real enemy is CO2, not pastoral-sourced methane.

As Upton points out, determining targets for methane emissions is a policy decision for Government. Given the huge difficulty in getting to zero carbon dioxide emissions, then the Government could in theory ask agriculture to do even more and reduce methane emissions to a level where future pastoral-sourced methane levels in the atmosphere contribute to global cooling.  That perhaps unlikely scenario would truly place agriculture on the moral high ground!

Those of us in agriculture also need to acknowledge that there are issues with nitrous oxide (N2O) that need to be considered. Unlike methane, this gas is long-living. However, whereas the supposed methane problem has largely been considered intractable, for nitrous oxide we do have a number of technologies that can reduce these emissions from manure and soils.

In summary, the societal negativity towards agricultural emissions of greenhouse gases has been influenced by false information by people who have shaped the narrative in line with simplistic understandings of the science.  The axis of the debate is now slowly changing.

That is not to say that the debate is over. Indeed, there is a long way to go. To paraphrase a statement from earlier this year by Federated Farmers spokesperson Andrew Hoggard, agricultural leaders will still need to step up to the table because agriculture will still be on the menu.

Currently, the understandings of the science amongst agricultural industry leaders leaves a lot to be desired. The same can be said of key policy makers in Government, none of whom appear to have a strong science background.

It is unfortunate that the overall climate change debate is very much influenced by noble-cause corruption. On both sides, it is easier to shape the so-called facts to fit prior beliefs, than to engage in genuine informed debate, independent of personal and strawman attacks. That is unlikely to change. Already, some have had a crack at Upton from both sides.

*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. He can be contacted at

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As someone who spends a bit of time observing opinion on this issue, there seems to be an alliance between animal rights activists and the oil industry shaping the narrative. Many people believe that ruminants are responsible for the majority of global warming, and all it needs is to get rid of them to solve the problem.

As someone who also follows this your comment is news to me.

Plus the chances of such an alliance is frankly about zero IMHO.

Sure some hard core vegans push this but frankly they are a tiny minority few if any ppl listen to, so i wouldnt worry on it.

Let's be clear on this.

Methane is much shorter lived than CO2, but vastly more damaging. If you equalize the impacts over 100 years (well past the life of Methane in the atmosphere) then methane is roughly 28 times more damaging from a climate change perspective than CO2 is. That's even though methane is doing no damage for most of that timeframe because it's already done it's damage and gone.

The other thing to be clear on is that it's not in 100 years to 200 years that we have a problem. It's in the next few decades. If these issues aren't addressed by 2050 we have some serious problems.

With that info, everyone can see how methane is a much bigger issue than carbon. Much bigger.

You are correct in your first statement on the basis of equalising impacts over a 100 year period.
And you would also be partly correct in your subsequent statements, if we were only interested in the future of the world over the next 100 years.
You also need to take account of the fact that there is a lot more carbon dioxide than methane being emitted into the atmosphere, so it is not just a case of looking at the energy absorption per molecule.
Accordingly, your final paragraph is totally incorrect.
Keith W

I would say a) it is indeed the next few decades, b) seems strange but the articles I have been reading seem to be almost panicking over methane. This could be because while you mention present day animal emissions you dont seem to mention the impact of historic methane under the like of perma frost or deep sea. So total methane could actually take off. Arguably then there is a need for drastic emissions just to compensate foor the increase of old methane being released.

Correct me if I'm wrong here, but doesn't atmospheric methane break down to CO2 and water anyway.. so it's always going to be worse than CO2.

CH4 + 2 O2 -> CO2 + 2 H2O if I recall correctly.

Keith - you are right that in total there is more carbon dioxide than methane being emitted. However when you take into account how much more damaging methane is (28 times on a 100 year basis), then the global warming impact of methane is about the same as carbon dioxide for NZ. Between them it's just less than 90% of the damage, with carbon dioxide only a few percent higher. Also, the rest of that damage is mainly nitrous oxide, which is also related to agriculture.

And my main point, is that if we are worried about 2050 as some sort of D-day for the impacts of climate change, and we compared the 2 gases on a 30 year basis, then methane is roughly 3 times more damaging than carbon, taking into account the relative volumes and everything else. Now of course carbon will continue to do damage for centuries, but by then we will have already stuffed the climate up unless we address these issues now.

Finally, your article gives the impression that short lived gases aren't an issue and long lived gases are. The reality of this situation is that BOTH are a roughly equivalent issue on a 100 year basis, and methane is much more damaging on a 30 year basis.

Your article gives a skewed impression of reality, which I don't find helpful to the discussion. Farmers (and you) are trying to pretend like methane isn't an issue because it's short lived.

That's demonstrably false.

If you read the articles I have written (google my name and methane, or short-lived gases), you will be unable to find any statement that says pastoral methane is unimportant. Others may have said that but I have never said it. Back in May, I wrote in an article here at (and also published elsewhere): "Within the current context of the Paris Agreement, agriculture emissions are indeed important and that includes methane" And if you read the second paragraph of this current article here to which you are responding, you will see that I explicitly make the point that I am not saying methane is unimportant. So please stop putting up strawmen to then shoot down.

There is nothing special about 2050 in terms of the science. It is simply a convenient date set in a political context. It has been chosen to highlight that, according to specific IPCC scenario (which not everyone agrees with) certain things need to be achieved before then to prevent particular outcomes thereafter. If one chooses a particular point in time thereafter, say 100 years from now, then at that point in time the current short-lived emissions will have almost totally gone (<1% remaining) whereas the long-lived gases will remain (to a large extent) , and will be the dominant drivers of climate at that time.

We can expect "the narrative" to keep changing for a long time but we have to do something (well, quite a lot) now. It's very likely that some actions may later seem irrelevant.

The Climate Commission is there to keep up with the detail on all the argument discussion points and can probably do that. Whether the politicians and everyone else can take advice they don't like is another matter.

See abstract p.61

Promising result found:

Run five reduced cow numbers by 23% to 2.2 cows/ha, removed imported supplements, N fertiliser and 15 ha of winter Oats. The results showed run five increased profits by 14% and decreased N-loss by 43% over the base system; this would make the farm meet the 20 year set limit imposed by the One Plan by 39% (N-loss).

I've always felt that if we can get on top of these water quality issues - the methane emissions would be all but solved as well.

Which aligns to this type of approach;

- accelerate energy innovation,
- build resilience to extreme weather, and
- pursue no regrets pollution reduction measures

A cautionary note is that this is a non peer reviewed modelling exercise.
But yes, there are solutions to the water quality issues.
Keith W

And do you agree, those solutions all 'kill two birds with one stone'?

Yes, but I am not sure that we agree on the strategy that will move us to the solution.

'Another 0.5 percent improvement per annum over the next 30 years and we will be well ahead of any zero-warming targets'.

That's a bit loose isn't it? We've already passed the 1.5 degree ppm, word is (Helen Clark/Nat Radio - she's probably got some inside gen) that there's only a 5% chance we keep below 2 degrees.

Kate - it pays to think it all through. Agribusiness as practiced burns 12 calories of ff to produce 1 calorie of food. It is therefore, in current form, unsustainable in terms of draw-down and is an emitter of CO2.

Yes, I'd heard that stat - and the average amount of freshwater needed to produce one litre of milk as well. But while there is still a large market for animal proteins, we need to change our local practices urgently.

The good thing about that study is that it is agribusiness as not presently practiced - in other words, this type of re-think on fewer cows/better profits is needed very swiftly - otherwise we'll have lost all our native fish species well and truly before 2050.

Remove all trout and introduced fish species and watch native fish rebound. ;-) And while we are at it set limits for whitebait and enforce them. Native freshwater fish species listed as threatened with, or at risk of, extinction include taonga species – such as īnanga, shortjaw kōkopu, giant kōkopu, kōaro (all are whitebait species)
In Central Otago the increasing number of people fishing and potential to put pressure on fish numbers has now resulted in daily limits being lowered on CO waterways. It’s more a reflection of [population] growth and it’s a reflection of our council wanting to take a precautionary approach ... and sharing the resource into the future." Well done Otago F & G. Hopefully the powers that be in regards to whitebait can grow a pair, and limit whitebait catch.

Perhaps one of the biggest issues National-scale information on the abundance, distribution, and trends in freshwater fish is currently limited. To overcome this limitation, trends in abundance of freshwater fish were analysed using data from the New Zealand Freshwater Fish Database (NZFFD). However, anyone can enter information in the NZFFD (ie there are no set sites or methods used for capturing fish), which means there are sampling differences across sites and time.
Native fish can live in water that is quite degraded - trout can't.
There has never been any nationwide survey of fish in on farm waterways. I am aware of critically endangered native fish being found in on farm waterways when consents required the waterway to be checked. Prior to that check their existence had never appeared on any data set.

Until we have a robust data set and on farm waterways are checked we are simply guessing at the numbers of native fish and the real situation regarding their endangerment or otherwise is simply another guesstimate.

Powderdown kiwi,
1) Helen Clark has no 'inside gen' that is not available to those who read the science.
2) Most of the calories used in agriculture come to us courtesy of the sun and photosynthesis.
But yes, it will indeed be challenging to sustain future global populations without fossil fuels to drive those tractors Some of us are working on those issues.

Keith - Between IPCC reports, there are just sporadic papers. But I suspect the top end of the UN are as informed as anyone.

It seems to me that folk like Jaqueline Rowarth (9 billion by 2050 - via Pundit) and Rod Oram (10 billion by 2050 via The Big Questions) are projecting straw-man arguments. Two or three of those projected billions are not here, presently - and condoms require less energy than monocultural agribusiness feeding 2-3 billion. Solves/reduces almost every other problem too.

I 'd be interested in what is being applied to tractor/transport development, might get in touch some time.

Precision agriculture and zero till have been and continue to provide efficiencies.
Increasing animal productivity continues to increase outputs relative to inputs,
Various nutrient recycling projects reduce nutrient losses.
Global populations continue to increase globally with most but not all of this of this relating to Africa and the Middle East.
The one country that did take drastic action to limit population growth was China and they were heavily criticised for it.
You are correct in implying that NZ agricultural technologies have limited application in most of the world.
There are lots of global challenges ahead,

PDK, there are big changes in agriculture, it's hard for me to put it all together into some form of coherent thought or idea, just too many potential outcomes. They say in the EU that robots now can do %14 of existing jobs and looking at %34 in 10 years.

In farming it's almost certainly worse on farm as tractors go self driving etc, I'm not so sure on the livestock side but perhaps the challenge there is from artificial meat and dairy products.

The GM industry is still making big inroads into food production, in Manitoba they can now grow maize, so you go from 12 tonnes a hectare to 21. Canada is a big Soy producer and they have this thing called Identity-preserved (IP) which tracks the Soy from the farm to the end user. If you shorten the time for a plant to grow then you push it further north, GM crops have changed cropping in Canada. China is the market.

Russia is opening up enormous amounts of land and yet Brazil has more underdeveloped farm land than Russia and the USA/Canada combined. Russia is more stable and I have talked to Kiwi farmers in Russia who say it's just the most amazing exciting place to be at present.

All this GM cropping is dependent on Glyphosate, they tell us we have 60 years of soil left if we keep cropping the way we do, I think we can tweak the system to fix that but it will require the present generation to pass the baton to a generation who thinks differently and it won't work if we go corporate.

Food is a lot cheaper of as a percent of our weekly income than it's ever been, farming efficiencies have been passed on, middlemen capture more than the grower. It takes a changing attitude and we are miles away from there, there is huge potential to produce in agriculture, there is huge amounts of investment available, farming is going corporate, these corporates will integrate with markets, be more willing to use GM plants and have the capital for automation. They will go were land is cheap, already over 200 farms in Russia grow over 100,000 hectares of wheat and in Brazil farms can be as big as 360,000 hectares. Soros alone grows 1million tonnes of Soy in Argentina, the families who used to farm the Pampas have been pushed out by large scale farm operations.

It's the availability of credit thats enabled this change and it's change in credit that will decide the future, the Eurodollar funding mechanism the ability of banks to take risk and then get bailed out by the taxpayer, the wealth of the %1 and if they can hold onto it in an increasing restless impoverished society, thats where the action is going to be.

Farming is going to change, I just don't think most of us are ready for whats coming. China is paying top dollar at the moment, I just don't know why.

Thanks AJ - thoughtful post. One of my concerns is that the whole planet is actually 'occupied' doing something - Brazil for instance has (had?) a rainforest once described as 'the lungs of the planet'.
This graph shows the magnitude of the problem:

Forty years ago Catton called us Homo Colossus. We've doubled the number of mouths since then. But I think you're right - food isn't being properly valued. But I think the future will see financial collapse global-trading-wise (think the closing of borders is part of that onset) and agriculture gets very local, very fast thereafter. Needs fertile seed too - goodbye Monsanto. I think mass starvation follows closely on the heels of a trading-system haemorrhage.

Hereabouts those who have seen it coming are setting up food networks

which aren't needed untill they'll be needed too much.

There seems to be more mainstream media coverage of the problems with glyphosate in the US now that Monsanto is owned by a German company, Bayer. It seems the media censorship ban on criticising Monsanto may have been lifted. The whole genetic modification issue makes my skin crawl.

" it will indeed be challenging to sustain future global populations without fossil fuels to drive those tractors Some of us are working on those issues.."

Without fossil fuels there are no incomes and no jobs. No such thing as Capitalism.
Burning through stuff is basically how we create & sustain capitalist growth.
Which is why the system collapses if we cant increase our Gross energy burn.

Methane shares the same absorption band as the Godzilla of greenhouse gases - water vapour. Atmospheric methane at 1.8 parts per million is swamped by water vapour. Any radiation that methane might absorb has already been absorbed by water vapour.

"CH4 forcing is nonetheless dependent on atmospheric state. The primary reason for this water vapour dependence is that mid-infrared CH4 absorption occurs at the edge of a strong H2O absorption band. Therefore, elevated H2O mixing ratios saturate the CH4 band and reduce the latter molecule’s radiative forcing."

The inevitable Mr Profile, obfuscator of all Climate-related discussion.

Atmospheric water-vapour is, unfortunately, likely to increase due to feed-back repercussions of our own making. The ocean temps recorded when we were sailing the pacific were astoundingly high in places - there is simply more evaporation going on.

CO is another I've caught out with spin before today, eh CO? Volumes of effluent, as I recall (I guess that's what spin is too, in a way). You have a valid point re trout, but not as a reason to continue muddying the waters..:).

PDK, thanks for your ocean going weather reports. Life is good. You can relax further - your "likely" feedback isn't happening. Relative humidity has been decreasing over time not increasing - going by the ESRL data. Or am I obfuscating?

You cant resist lying can you. You have no scientific basis for your denier point of view so continue to take out of context. sceintific papers ie you take a paragraph out of context as per usual trying to claim its supports your view, when in fact it does not.

Great thing about providing links of course is ppl can just read them.

Also not sure what you hope to gain by attempting to link to scientific papers but there are some land mines in there you stepped on as per usual, maybe better not to.

"However, the methods used by that report were last revised in 199817, and recent work has indicated that an upward revision to the methane radiative forcing formulae and the determination of its global warming potential for future assessment reports is necessary18, mostly due to the need to include short-wave effects."

In summary as we emit more CO2 and emission of methane increases the planet will warm simple observed fact based on sound science. Warmer means there will be more water vapour, its known as a feedback mechanism simple observed fact backed up by science. So sure more water vapour may have a negating effect per molecule so each methane molecule may not have as big an effect as expected but when you get a lot more molecules the NET effect is even more warming.

So emotive Steven. Your quote from the introduction refers to models not the real world whereas the paper I linked deals with real world observation. Look at the papers title! "Observationally derived rise in methane surface forcing mediated by water vapour trends". Note the word "mediated".

Also note in the introduction "The spectroscopy of CH4, which is the foundation underlying the radiative forcing calculations, is an active area of research. This is because CH4 exhibits a line structure of exceptional complexity compared to other atmospheric greenhouse gases." Hardly the basis for a taxation/levy system!

Likewise in the conclusions note " Since local temperature and humidity trends that are distinct from those at the SGP exist at other sites, the relative contributions of thermodynamics and mixing ratio changes to the forcing may also differ. Observed trends in surface humidity have not been spatially or temporally uniform, nor have they been monotonic. The magnitude of the globally averaged land-surface humidity trend varies on decadal timescales while also exhibiting trends that are spatially variable over land and that show strong land–ocean contrast.

Therefore, the direct impact of greenhouse gases on the surface energy balance cannot be predicted in isolation from thermodynamics."

Reminds me of the late Bob Carter.

Who learned to be a Singer late in life.

His last slide always had me in stitches.

As does your last quoted sentence.

And I'm not renowned for getting up early in the morning - you need to raise your game.

Stopped reading when you wrote "denier".

To get anywhere , the farming advocates need to stop trotting out ," NZ farmers are the most efficient in the world", as a response to any constructive criticism/ideas. A google search does not mention NZ. It appears we are telling ourselves we are. The rest of the world could learn a lot from us , but there is also a lot we could learn from overseas best practice.One major example is shelter for animals in the height of summer and winter. Not only is it more humane, its more efficient. Yet shelterbelts are been ripped out. barns and feed pads/lots are not given a fair go , farm forestry is also downplayed. Fair enough , its easier to grow grass, but I'm abit surprised there is not more research into these practises. what studies that have been done almost always have positive results. Look at planting poplar/willows as fodder on steep hills/wet areas. Every study I have read (mostly by regional councils) have reported positive results. It is now accepted practice. Lets look to other ways of efficiently growing fodder trees and soaking up extra nutrients.

Aussies think we are a bunch of Ar$%()(#$ banning LNG

Gas is one of the cleanest energy sources producing mostly water , unlike Petrol which produces Carbon dioxide and diesel which produces Sulphur and co2 and of course coal which produces all manner of toxins

So why are we banning one of the cleanest energy sources on the planet ?

... they're banning nat gas exploration for the exact same reason they've torn up the charter school system ... 'cos they're ideologically opposed to them ...

Regardless that the facts say these are two dreadfully stupid decisions by Taxinda .... they've pushed ahead anyway ....

... we can but hope this is a very short lived government ... and that the big kids will be back running the place soon ... as the toddlers are totally out of their depth ...

That's a sad little piece of mantra-chant from the past - Sort of reminds me of formica tables and three china ducks.

Boatman - The whole point about gas, at this stage in our overshoot, is that it is essentially finite, requires a whole set of dedicated infrastructure, and the infrastructure needs a build, inevitably using oil/coal. Then you need to build the renewable infrastructure to take over - long before the gas infrastructure has done a 'lifetime'.

So it's silly. The only valid approach is to build the renewable infrastructure, while there is still some resilience in the current energy system. The only argument for gas is that it can - sort of - be run in existing vehicles, but we went there once. Remember? With much less complex vehicles too.

And the problem with putting the dinosaurs back in control, is that they were hastening us towards extinction. In future I will address GBH as Mr. Halszkaraptor.

Gummy Often you say something interesting but this...
Straight out of the Trump copy book...
Name calling, overstatement, content less, grumpy unhinged rant.
Could be in the white house

Yay, Gummy For President.

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